Supporting Information. Ana Montero, John M. Beierle, Christian A. Olsen, and M. Reza Ghadiri *

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1 Supporting Information Design, Synthesis, Biological Evaluation, and Structural Characterization of Potent Histone Deacetylase Inhibitors Based on Cyclic α/β-tetrapeptide Architectures Ana Montero, John M. Beierle, Christian A. lsen, and M. Reza Ghadiri * Contents: Supporting Schemes Experimental Methods Compound Characterization Figure S1 RESY Tables NMR Spectra Page: S2 S2 S4 S7 S8 S15 S1

2 Supporting Schemes Scheme S1. Synthesis of (S)-Boc-Aoda-H (S6) using the Schöllkopf method. S1 Br S1 Me N N Me + Br -78 to -50 o C LDA, THF Me N N Me i) HCl ii) Boc 2 BocHN Me LiH BocHN H S3 S2 S4, 96% S5, 61%, 2 steps S6, 99% Scheme S2. Synthesis of (S)-Fmoc-Aoda-H (S10) and (R)-Fmoc-Aoda-H (S12) employing enzymatic resolution (adapted from a literature procedure S2 ). H a AcHN CEt + I CEt S7 NaH, DMF CEt EtC AcHN S8, 75% i) DMS, LiCl, heat ii) LiH AcHN H S9, 62%, 2 steps i) Acylase-I ii) Fmoc-Su FmocHN H S10, 41% + b AcHN S11, 16% AcHN H S11 10 N HCl, heat HCl H 2 N H Fmoc-Cl FmocHN H S12, 89%, 2 steps Experimental Methods 12 General. Fmoc α-amino acids, chlorotrityl resin, 2-(1Hbenzotriazol-1-yl)-1,1,3,3,-tetramethyluronium hexafluorophospate (HBTU), and 2-(1H-azabenzotriazol-1- yl)-1,1,3,3,-tetramethyluronium hexafluorophospate (HATU) were purchased from Novabiochem (San Diego, CA). 2-Chlorotrityl N-Fmoc-hydroxylamine resin was from Sigma-Aldrich (Milwaukee, WI). β-amino acids were purchased from Peptech Corporation (Burlington, MA). Unless otherwise noted, all solvents and chemicals were reagent grade and were used as received. When needed, reactions were carried out under an inert atmosphere of dry argon or nitrogen using distilled dry solvents. Reactions were monitored by TLC analyses using aluminum-backed silica gel plates (Merck Kieselgel 60 F 254 ) with UV light for visualization. Flash column chromatography was carried out on Merck silica gel 60 ( mesh) and vacuum liquid chromatography (VLC) was performed on Merck silica gel 60 (45 60 mesh). Recombinant human HDAC isoforms were purchased from BPS Biosciences (San Diego, CA). S1 Kim, S.; Kim, E.-Y.; Ko, H.; Jung, Y. H. Synthesis 2003, S2 Kahnberg, P.; Lucke, A. J.; Glenn, M. P.; Boyle, G. M.; Tyndall, J. D. A.; Parsons, P. G.; Fairlie, D. P. J. Med. Chem. 2006, 49, Solid-phase synthesis and solution-phase cyclization of Aoda-containing peptides (compounds 1 3, 4 7). Linear peptides were synthesized using chorotrityl resin via standard Fmoc peptide synthesis protocols (HBTU ipr 2 EtN). Treatment of the resin with TFA CH 2 Cl 2 H 2 (49:50:1) for 2 h effected concomitant cleavage from the resin and removal of the N-terminal Boc group. The resins were washed twice with neat TFA, and the combined filtrates were concentrated to provide the linear peptides as oily residues that were subsequently cyclized without further purification. Formation of the corresponding cyclic derivatives was carried out in solution under dilute conditions ( mm in DMF) using ipr 2 EtN (4 equiv) and HATU (2 equiv) as coupling reagent. The DMF was evaporated under reduced pressure and the residues were purified to homogeneity (>95%) using reversed-phase HPLC (C-18 column, H 2 /MeCN/TFA solvent system). The HPLC solvents were lyophilized to give the cyclic products as fluffy white solids that were characterized by 1 H NMR, LC-MS, and high resolution mass spectrometry (ESI-TF MS). Solid-phase synthesis with on-resin cyclization (compounds 3a c and 4a b). (S)-Fmoc-Asu(t-Bu)- Allyl S2 (3 equiv with respect to the resin) was stirred in TFA CH 2 Cl 2 (1:1) for 1 h to remove the t-butyl protecting group. The solvents were then evaporated in vacuo, the residue was co-evaporated several times with CH 2 Cl 2 S2

3 hexanes, and the residue was then dried for 2 h under high vacuum. For preparation of the compounds containing side chain acids (3b and 4b), the TFA-free (S)-Fmoc-Asu- Allyl residue was taken up in CH 2 Cl 2 (2 ml/100 mg) and ipr 2 EtN (20 equiv), and was shaken with trityl chloride resin in a fritted syringe for 16 h to give the side chainloaded starting resin. For preparation of the side chain hydroxamic acid (3a and 4a) or amide compounds (3c), the (S)-Fmoc-Asu-Allyl residue was coupled to a hydroxylamine-loaded trityl resin or a Rink amide resin, respectively, using HATU as the coupling reagent. After loading, the resins were washed with DMF, MeH, and CH 2 Cl 2 (3 each), and the resin loading was determined by UV measurement (290 nm) of the chromophore in an Fmoc deprotected sample (Novabiochem procedure). The resin was then Fmoc deprotected using DMF piperidine (3:1, 2 20 min), washed with DMF, MeH, and CH 2 Cl 2 (3 each), and dried in vacuo. The three remaining amino acids were coupled via standard Fmoc SPPS carried out in 3 ml fritted syringes, applying the Fmoc protected amino acids (4 equiv), HBTU (4 equiv) and ipr 2 EtN (4 equiv) in each coupling step. Standard Fmoc deprotection and washing protocols were followed. After coupling the final amino acid, the resins were washed with DMF, MeH, CH 2 Cl 2, and Ar degassed CHCl 3 N-methylmorpholine (3 each). The allyl group was then cleaved by treating the resin with Pd(Ph 3 P) 4 (0.2 equiv) in degassed CHCl 3 Nmethylmorpholine (4 ml) while shaking for 16 h in the dark, after which time the resin was washed with DMF, 1% sodium dimethylthiocarbamate in DMF, and DMF again (2 each), followed by Fmoc deprotection and standard washing. Finally, the resin-bound peptides were cyclized (2 12 h) with HATU (5 equiv) and ipret 2 N (20 equiv) in DMF (3 ml), washed extensively, and dried under high vacuum. Crude cyclic peptides were cleaved with 1:1 TFA CH 2 Cl 2 in the cases of the trityl resins (3a, 3b, 4a, 4b) or 95:5 TFA CH 2 Cl 2 in the case of the Rink amide resin (3c). The resins were washed twice with neat TFA and CH 2 Cl 2, and the combined filtrates were concentrated in vacuo. The residues were purified to homogeneity (>95%) using reversed-phase HPLC (C-18 column, H 2 /MeCN/TFA solvent system). The HPLC solvents were lyophilized to give the products as white fluffy solids that were characterized by 1 H NMR, LC-MS, and high resolution mass spectrometry (ESI-TF MS). IC 50 determinations. Concentrations of peptide stock solutions for biological testing (prepared in DMS) were determined using UV spectroscopy [ε Trp = 5690 M -1 cm -1 (280 nm)]. HDAC assay buffer (used for both HeLa cell extract assays and recombinant human HDAC isofom assays) was prepared as described in the Biomol International protocol [Tris/Cl (50 mm), NaCl (137 mm), KCl (2.7 mm), MgCl 2 (1 mm), ph 8.0]. The IC 50 values in HeLa cell nuclear extracts were determined using the standard Biomol International HDAC fluorimetric assay protocol (AK-500). Recombinant human HDAC isofom assays were carried out according to protocols given by the HDAC supplier (BPS Biosciences). Briefly, dose response experiments with apicidin included as internal control were carried out using black low binding NUNC 96-well microtiter plates. Peptide stock solution dilutions were prepared in Milli-Q water from 1 mm DMS stocks. The appropriate dilution of the inhibitor (10 µl of a 5 concentration solution) was added to each well followed by HDAC assay buffer (25 µl), bovine serum albumin (5 µl, 1 mg/ml) and HDAC assay substrate (BPS Biosciences catalog no , 5 µl, 200 µm). Finally, a solution of the appropriate HDAC (5 µl) was added and the plate was incubated at 37 C for 30 minutes in the dark. Developer (50 µl) was then added, and the assay development was allowed to proceed for 15 minutes at RT before the plate was read using a Tecan GENios plate reader exciting at 360 nm and detecting emision at 460 nm. A semi logarithmic plot of the data was analyzed using GraphPad Prism to obtain IC 50 values. Cancer cell cytotoxicity assays. Cells were cultivated in flat 96-well tissue culture plates in 0.08 ml of medium supplemented with 10 % Fetal Bovine Serum and antibiotics. HeLa and Huh-7 cell lines were seeded at a density of 5,000 cells/well, MCF-7 at a density of 10,000 cells/well and K-562, KY-1, and Molt-3 were seeded at a density of 15,000 cells/well. Twenty-four hours later, 0.02 ml of medium containing various concentrations of the desired compounds were added and the cells were incubated at 37 C for 72 h. Cell survival was determined using the XTT (Sigma-aldrich, St. Louis, M) colorimetric assay. S3 Immediately prior to use, a mixture of XTT (1 mg/ml) an d PMS (N-methyl dibenzopyrazine methyl sulfate, mg/ml), (0.1 ml of PMS per 5 ml of XTT solution were added) in phenol red free RPMI was prepared. After adding 0.05 ml of this mixture to each well, plates were incubated at 37 C for 2 h in the case of HeLa, MCF-7, and Huh-7 cells, and 4 h in the case of K- 562, KY-1, and Molt-3 cells. Plates were shaken to evenly distribute the dye in the wells and the absorbance was measured using a Tecan GENios plate reader spectrometer at a wavelength of 435 nm. A plot of the data was used to determine the corresponding GI 50 values. Apicidin and the vehicle were used as positive and negative controls respectively. Structural determinations by multidimensional NMR. All spectra were obtained on a Bruker cryo-drx-600 MHz instrument using ~5 mm concentrations of peptide in DMS-d 6 under a regulated temperature of 300 K. Twodimensional experiments were recorded using 2048 data points in the direct dimension and 512 data points in the S3 Roehm, N. W.; Rodgers, G. H.; Hatfield, S. M.; Glasebrook, A. L. J. Immunol. Methods 1991, 142, S3

4 indirect dimension. A mixing time of 200 ms was employed for RESY spectra. Integrations were carried out using the program NEASY followed by peak sorting and normalization via Microsoft Excel. Using the equation I = cr -6, where I is peak intensity, r is distance between protons, and c is a constant, the NE measurements were converted to a scale of strong ( 2.7 Å), medium ( 3.5 Å) and weak ( 4.5 Å) using the NEs of two geminal CH 2 protons as a standard. Structure calculations were carried out using Crystallography & NMR System (CNS). Two patches were written: one for the unnatural Aoda residue and another to modify an a-amino acid to a b 3 -amino acid. As a control, an initial set of 50 calculations not using NE restraints was carried out for each structure to confirm that diverse conformations were sampled during the calculations. Following this control, a minimum of two systematic annealings using the NE distance restraints was carried out, one in which all amide bonds were fixed in a trans configuration and another in which the restraints were loosened to investigate the possibility of cis trans isomerization of the amide bonds. The trial structures resulting from these annealings that did not violate the NE data by more than 0.2 Å were identified as accepted structures; out of the systematic annealing calculations carried out for each compound, the calculation providing the greatest number of accepted structures was retained for the final step of structure determination. For all compounds except 3i, a final inspection of each accepted structure was conducted manually to remove any accepted structure that contained a cis amide bond, since no NEs indicative of cis amides (such as cross residue couplings of H α - H α, H α - H β, or H α -H β3 ) were present even at high intensity in the RESY spectrum for any peptide except compound 3i. Compound Characterization 8-Bromooctan-3-one (S1). S4 To a solution of 1- ethylcyclohexanol (2 g, 15.6 mmol) in MeCN (50 ml) at 0 C was added powdered K 2 C 3 (12.9 g, 93.6 mmol). The mixture was stirred for 10 minutes and bromine (4 ml, 77.9 mmol) was then added dropwise. The reaction mixture was stirred at 0 C for 3 h and then quenched with a sat. aq. Na 2 S 2 3 solution and extracted with EtAc (2 50 ml). The combined organic layers were washed with brine, dried over MgS 4, filtered, and concentrated under reduced pressure. The resulting crude oil was purified by flash column chromatography (silica gel; hexanes-etac, 9:1) to yield S1 (3.0 g, 93%) as a colorless oil. 1 H NMR (400 MHz, 300 K, CDCl 3 ) δ 3.39 (t, J = 6.7 Hz, 2H), 2.41 (q, J = 7.3 Hz, 2H), 2.40 (m, 2H), 1.85 (m, 2H), 1.59 (m, 2H), 1.42 (m, 2H), 1.04 (t, J = 7.4 Hz, 3H). 2-(5-Bromopentyl)-2-ethyl-[1,3]-dioxolane (S2). To a stirred solution of the bromoketone (S1) (2.9 g, 14 mmol) in benzene (20 ml) was added ethyleneglycol (1.95 ml, 35 S4 Zhang, W.-C.; Li, C.-J. J. rg. Chem. 2000, 65, mmol) and camphorsulfonic acid (325 mg, 1.4 mmol). The mixture was heated at reflux overnight in a Dean Stark apparatus. After cooling to RT, the mixture was poured into a sat. NaHC 3 solution and extracted with Et 2. The organic layers were combined, washed with brine, dried over anhydrous MgS 4 and concentrated to give a crude residue that was purified by flash column chromatography (silica gel; hexanes-etac, 15:1) to give S2 as colorless oil (3.2 g, 91%). 1 H NMR (400 MHz, 300 K, CDCl 3 ) δ 3.92 (s, 4H), 3.40 (t, J = 6.8 Hz, 2H), 1.86 (m, 2H), 1.61 (m, 4H), 1.41 (m, 4H), 0.89 (t, J = 7.4 Hz, 3H). 2-[5-(2-Ethyl-[1,3]dioxolan-2-yl)-pentyl]-5-isopropyl-3,6- dimethoxy-2,5-dihydropyrazine (S4). A solution of freshly prepared LDA (2.2 mmol) in THF (4 ml) was added to a stirred solution of the Schöllkopf chiral auxiliary S3 (0.358 ml, 2.0 mmol) in THF (6 ml) at 78 C. The mixture was stirred for 30 minutes and then a solution of the alkyl bromide S2 (0.552 mg, 2.2 mmol) in THF (4 ml) was added dropwise. The reaction mixture was warmed to 60 C and stirred at this temperature for 16 h. The solution was quenched with Tris buffer solution (ph = 7.0) and the organic solvent was evaporated in vacuo. The resulting crude material was diluted with water, washed with EtAc, and the combined organic layers were the dried over anhydrous MgS 4, filtered, and concentrated. The resulting material was purified by flash column chromatography (silica gel; hexanes EtAc, 15:1 10:1) to give pure S4 as a colorless oil (96%). 1 H NMR (500 MHz, 300 K, CDCl 3 ) δ 4.01 (m, 1H), 3.92 (s, 4H), 3.68 (s, 3H), 3.67 (s, 3H), 2.26 (m, 1H), 1.78 (m, 1H), 1.69 (m, 1H), 1.61(q, J = 7.5 Hz, 2H), (m, 3H), (m, 6H), 1.04 (d, J = 6.9 Hz, 3H), 0.89 (t, J = 7.5 Hz, 3H), 0.68 (d, J = 6.9 Hz, 3H). Methyl-2-(tert-butoxycarbonylamino)-8-oxodecanoate (S5). To a solution of S4 (651 mg, 1.83 mmol) in THF (8 ml) was added aq. 0.1 N HCl (1.4 ml). The mixture was stirred at RT for 16 h, and after this time the solution was basified (ph 11) with ammonium hydroxide and extracted with EtAc. The combined organic layers were washed with brine, dried over anhydrous MgS 4, filtered, and concentrated in vacuo. The resulting crude amino methyl ester was dissolved in 1,4-dioxane H 2 (1:1) and then NaHC 3 (615 mg, 7.32 mmol) and di-tert-butyldicarbonate (1.19 mg, 5.49 mmol) were added. The mixture stirred at RT for 16 h, and then solvents were removed in vacuo. The resulting crude material was diluted with EtAc, washed with water and brine, and the resulting organic layer was dried over anhydrous MgS 4, filtered, and concentrated in vacuo. Purification by flash column chromatography (silica gel; hexanes-etac, 9:1 8:2) gave S5 (61%, two steps) as a colorless oil. 1 H NMR (500 MHz, 300 K, CDCl 3 ) δ 4.98 (d, J = 7.5 Hz, 1H), 4.27 (m, 1H), 3.73 (s, 3H), 2.48 (q, J = 7.3 Hz, 2H), 2.47 (m, 2H), 1.78 (m, 1H), (m, 3H), 1.44 (s, 9H), (m, 4H), 1.05 (t, J = 7.3, 3H). (S)-Boc-Aoda-H (S6). To a solution of Boc-Aoda-Me (S5) (227 mg, 0.72 mmol) in THF H 2 (1:1, 10 ml) was S4

5 added LiH H 2 (33.2 mg, 0.79 mmol) and then the reaction mixture was let to stir at RT for 2 h. Solvents were removed in vacuo and the resulting crude material was dissolved in EtAc and washed with 5% HCl and H 2. The combined organic layers were dried over anhydrous MgS 4, filtered, and concentrated to give S6 (214 mg, 99%) as a colorless oil. The resulting Boc-Aoda-H (S6) was used without further purification. 1 H NMR (400 MHz, CDCl 3 ) δ 5.08 (d, J = 8.0 Hz, 1H), 4.27 (m, 1H), 2.39 (q, J = 7.4 Hz, 2H), 2.38 (m, 2H), 1.81 (m, 1H), 1.65 (m, 1H), 1.55 (m, 2H), 1.42 (s, 9H), 1.37 (m, 2H), 1.29(m, 2H), 1.02 (t, J = 7.3, 3H). (S)-N-Fmoc-Aoda-H (S10). For scale-up synthesis (>3 mmol) and preparation of (R)-N-Fmoc-Aoda-H we adopted the protocol previously described for enzymatic resolution of 2-(acetylamino)-suberic acid (SI, Scheme S2). S2 8-Bromooctan-3-one (S1) was stirred with NaI (2 equiv) in acetone at reflux for 16 h. After evaporation of the solvent and aqueous work-up, the crude iodide (S7, 3.61 g, 14.2 mmol, 1.1 equiv) was added to a cooled solution of diethyl acetamidomalonate (2.805 g, 12.9 mmol, 1 equiv) and 60% NaH (570 mg, 14.2 mmol, 1.1 equiv) in DMF (15 ml). This mixture was allowed to warm from 0 ºC to RT, and stirring was continued for 6 h. Then Et 2 (300 ml) was added and the organic layer was washed with water (3 75 ml), 0.1 M HCl (75 ml), sat. NaHC 3 (75 ml), and brine (75 ml), dried (MgS 4 ), filtered, and concentrated to give crude 2-acetylamino-2-ethoxycarbonyl-7-oxo-decanoic acid ethyl ester (S8), which was purified by vacuum liquid chromatography (3.32 g, 75%). This intermediate (3.27 g) was decarboxylated by heating to 150 ºC with LiCl H 2 (1.5 equiv) and water (2 equiv) in DMS (40 ml) for 24 h. After cooling to RT, the compound was extracted with Et 2 (2 200 ml), and the combined ether layers were washed with brine (100 ml), dried (MgS 4 ), filtered, concentrated, and dried in vacuo to give a yellow oil (1.9 g, 74%). Subsequent hydrolysis with LiH (440 mg, 10.5 mmol, 1.6 equiv) in EtH H 2 (1:1, 50 ml) for 1 h, followed by evaporation of the EtH, acidification (ph 3) with 1 M HCl, and aqueous work-up afforded the (rac)-2- acetylamino-7-oxo-decanoic acid (S9, 84%). The racemate was dissolved in phosphate buffer (0.1 M, ph 7.2, 150 ml) and the ph was adjusted to 7.2 with 2.0 M NaH. This solution was resolved by incubation at 37 ºC with CoCl 2 (16 mg) and acylase-i (Fluka, Aspergillus melleus, 1.06 U/mg, 160 mg) under Ar with gentle stirring for 16 h. At this time, 1 H NMR of an aliquot (100 µl) of the reaction mixture diluted with methanol-d 4 (1 ml) showed 50% deacetylation, and NaHC 3 (1.9 g) followed by Fmoc-Su (1.7 g, 5.0 mmol, 0.75 equiv) in 1,4-dioxane (50 ml) were added. Stirring was continued for 3 h at RT, then the 1,4- dioxane was evaporated in vacuo, the ph was adjusted to ~2 with 1 M HCl, and the carboxylic acids were extracted with EtAc (3 125 ml). The combined organic layers where washed with brine (75 ml), dried (Na 2 S 4 ), filtered, concentrated and purified by vacuum liquid cromatography on silica gel to give the (S)-N-Fmoc-Aoda-H (S10) as a colorless oil (1.14 g, 41%), which solidified upon freezing. 1 H NMR (500 MHz, CDCl 3 ) δ 7.76 (d, J = 7.4 Hz, 2 H), 7.58 (d, J = 6.7 Hz, 2 H), 7.37 (t, J = 7.2 Hz, 2 H), 7.30 (t, J = 7.4 Hz, 2 H), 5.38 (d, J = 8.2 Hz, 1 H), 4.40 (m, 3 H), 4.22 (t, J = 6.9 Hz, 1 H), 2.40 (m, 4 H), (m, 8 H), 1.04 (t, J = 7.3 Hz, 3 H); 13 C NMR (125 MHz, CDCl 3 ): 212.4, 176.8, 156.4, 144.1, 144.0, (2 C), (2 C), (4 C), 125.3, (2 C), 67.4, 53.9, 47.4, 42.4, 36.2, 29.0, 25.3, 23.8, 8.1; MS (m/z): [M+H] + calcd, ; found, ; and [M+Na] + calcd, ; found, The (R)-N-Ac-Aoda-H (S11) recovered from the resolution was deacetylated by treatment with 10 M HCl under reflux for 16 h, and then Fmoc protected as described above for the S-enantiomer to give (R)-N-Fmoc-Aoda-H (S12) as a colorless oil. Characterization data were identical to the above. Samples of each stereoisomer were Fmoc deprotected and treated with Marfey s reagent, and ee values were calculated from the obtained analytical reversed phase HPLCs [(S)-N-Fmoc-Aoda-H, ee = 99%; (R)-N-Fmoc-Aoda-H, ee = 96%]. c[aoda-β 3 Trp-Leu-Ala] (1). 1 H NMR (600 MHz, 333 K, DMS-d 6 ) δ (broad s, 1H) 7.90 (d, J = 6.4 Hz, 1H), 7.54 (d, J = 7.8, 1H, 7.47 (d, J = 9.9 Hz, 1H), 7.33 (d, J = 8.1, 1H), 7.26 (d, J = 9.8 Hz, 1H), 7.07 (m, 2H), 7.04 (m, 1H), 6.98 (dd, J = 7.8 and 7.9, 1H), 4.28 (dd, J = 9.9 and 7.4, 1H), 4.19 (m, 1H), 4.03 (q, J = 6.1 Hz, 1H), 3.93 (m, 1H), 2.90 (broad s, 2H), 2.39 (m, 4H), 2.28 (m, 2H), 1.67 (m, 1H), 1.61 (m, 1H), 1.45 (m, 2H), 1.39 (m, 1H), (m, 3H), 1.18 (d, J = 7.3 Hz, 3H), 0.90 (t, J = 7.3 Hz, 3H), 0.86 (d, J = 6.6 Hz, 3H), 0.79 (d, J = 6.6 Hz, 3H). ESI- TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-leu-β 3 Ala] (2). 1 H NMR (600 MHz, 333 K, DMS-d 6 ) δ (broad s, 1H) 7.95 (d, J = 6.1 Hz, 1H), 7.61 (d, J = 9.6, 1H, 7.53 (d, J = 7.8 Hz, 1H), 7.41 (d, J = 10.3, 1H), 7.32 (d, J = 8.0 Hz, 1H), 7.10 (d, J = 7.0, 1H), 7.06 (m, 2H), 6.98 (t, J = 7.3, 1H), 4.62 (m, 1H), 4.62 (m, 1H), 3.94 (m, 1H), 3.88 (m, 1H), 3.02 (m, 1H), 2.38 (q, J = 7.3, 2H), 2.34 (m, 4H), 1.51 (m, 1H), 1.48 (m, 2H), 1.44 (m, 2H), 1.37 (m, 2H), 1.17 (m, 1H), (m, 3H), 1.09 (d, J = 6.5 Hz, 3H), 0.93 (t, J = 7.3 Hz, 3H), 0.88 (d, J = 6.4 Hz, 3H), 0.78 (d, J = 6.4 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-(d)trp-leu-β 3 Ala] (2a). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-β 3 Leu-Ala] (3). 1 H NMR (600 MHz, 300 K, DMS-d 6 ) δ (broad s, 1H), 8.12 (d, J = 5.9 Hz, 1H), 7.68 (d, J = 9.8, 1H), 7.52 (d, J = 7.9 Hz, 1H), 7.49 (d, J = 10.3, 1H), 7.32 (d, J = 8.0 Hz, 1H), 7.27 (d, J = 7.6, 1H), 7.06 (m, 2H), 6.97 (t, J = 7.1, 1H), 4.73 (m, 1H), 4.10 (m, 1H), 3.98 (m, 1H), 3.94 (m, 1H), 2.99 (m, 1H), 2.98 (m, 1H), 2.38 (q, J = 7.2, 2H), 2.39 (m, 4H), 1.54 (m, 1H), 1.44 (m, 1H), 1.41 (m, 2H), 1.32 (m, 2H), 1.22 (d, J = 7.4 Hz, 3H), 1.17 (m, 1H), 1.09 (m, 2H), 1.03 (m, 1H), 0.92 (m, S5

6 1H), 0.91 (t, J = 7.1 Hz, 3H), 0.90 (d, J = 6.6 Hz, 3H), 0.86 (d, J = 6.6 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[asu(nhh)-trp-β 3 Leu-Ala] (3a). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[asu-trp-β 3 Leu-Ala] (3b). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[asu(nh 2 )-Trp-β 3 Leu-Ala] (3c). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-(d)trp-β 3 Leu-Ala] (3d). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-β 3 Leu-(D)Ala] (3e). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[(d)aoda-trp-β 3 Leu-Ala] (3f). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-(n-me)β 3 Leu-Ala] (3g). 1 H NMR (600 MHz, 310 K, DMS-d 6, mixture of conformations) spectral data for the major conformation: δ (broad s, 1H), 7.63 (d, J = 8.5 Hz, 1H), 7.57 (d, J = 7.8 Hz, 1H), 7.52 (d, J = 9.2, 1H), 7.32 (d, J = 9.5, 1H), 7.30 (d, J = 8.1 Hz, 1H), 7.04 (t, J = 7.0, 1H), 7.01 (d, J = 2.3, 1H), 6.97 (t, J = 7.0, 1H), 4.83 (m, 1H), 4.31 (m, 1H), 3.96 (m, 1H), 3.34 (m, 2H), 2.98 (m, 1H), 2.98 (m, 1H), 2.97 (m, 1H), 2.64 (s, 3H), 2.39 (q, J = 7.3, 2H), 2.36 (t, J = 7.3, 2H), 2.07 (m, 1H), 1.53 (m, 1H), 1.42 (m, 2H), 1.25 (d, J = 7.4 Hz, 3H), (m, 7H), 0.92 (t, J = 7.3 Hz, 3H), 0.76 (d, J = 6.2 Hz, 3H), 0.72 (d, J = 6.2 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-β 3 Leu-(N-Me)Ala] (3h). 1 H NMR (600 MHz, 300 K, DMS-d 6, mixture of conformations) δ (m, 1H), 7.60 (m, 1H), 7.50 (m, 1H), 7.31 (m, 1H), 7.16 (m, 1H), 7.05 (m, 3H), 6.96 (t, J = 7.8, 1H), 6.93 (m, 1H), 4.38 (m, 1H), 4.14 (m, 1H), 3.96 (m, 1H), 3.03 (m, 2H), 2.91 (m, 1H), 2.60 (s, 3H), 2.38 (q, J = 7.3, 2H), 2.36 (m, 4H), 1.53 (m, 3H), 1.46 (m, 1H), 1.35 (m, 2H), 1.31 (m, 3H), 1.25 (m, 1H), 1.18 (m, 3H), 0.97 (m, 1H), 0.89 (t, J = 7.3 Hz, 3H), 0.76 (d, J = 6.2 Hz, 3H), 0.72 (d, J = 6.2 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-(n-me)trp-β 3 Leu-Ala] (3i). 1 H NMR (600 MHz, 300 K, DMS-d 6 ) δ (broad s, 1H), 7.80 (d, J = 7.7, 1H), 7.56 (d, J = 8.3 Hz, 1H), 7.42 (d, J = 7.8 Hz, 1H), 7.27 (d, J = 8.0 Hz, 1H), 7.23 (d, J = 9.5, 1H), 7.06 (d, J = 2.3, 1H), 7.04 (t, J = 7.1, 1H), 6.97 (t, J = 7.7, 1H), 4.39 (m, 1H), 4.10 (m, 1H), 4.04 (m, 1H), 3.48 (m, 1H), 3.16 (m, 1H), 3.15 (m, 1H), 2.70 (s, 3H), 2.41 (q, J = 7.3, 2H), 2.32 (m, 1H), 2.21 (m, 3H), 1.55 (m, 1H), (m, 4H), 1.18 (m, 2H), 1.25 (d, J = 7.3 Hz, 3H), 0.95 (d, J = 6.5 Hz, 3H), 0.93 (d, J = 6.5 Hz, 3H), 0.91 (t, J = 7.1 Hz, 3H), 0.83 (m, 2H), 0.78 (m, 1H), 0.73 (m, 1H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-β 3 Leu-Pro] (4). 1 H NMR (600 MHz, 323 K, DMS-d 6 ) δ (broad s, 1H), 7.50 (d, J = 7.9 Hz, 1H), 7.45 (d, J = 9.2, 1H), 7.23 (d, J = 8.1 Hz, 1H), 7.06 (m, 2H), 6.97 (t, J = 7.1, 1H), 6.99 (m, 1H), 6.91 (m, 1H), 4.41 (m, 1H), 4.20 (m, 1H), 4.08 (m, 1H), 3.98 (m, 1H), 3.76 (m, 3H), 3.47 (m, 1H), 3.0 (m, 1H), 2.99 (m, 1H), 2.62 (m, 1H), 2.41 (m, 1H), 2.38 (q, J = 7.3, 2H), 2.33 (t, J = 7.3 Hz, 2H), 2.18 (m, 1H), 1.99 (m, 2H), 1.72 (m, 1H), 1.56 (m, 1H), 1.51 (m, 2H), 1.42 (m, 1H), 1.38 (m, 2H), 1.23 (m, 1H), 1.15 (m, 2H), 1.11 (m, 1H), 1.02 (m, 1H), 0.92 (t, J = 7.3 Hz, 3H), 0.90 (d, J = 6.5 Hz, 3H), 0.86 (d, J = 6.5 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[asu(nhh)-trp-β 3 Leu-Pro] (4a). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[asu-trp-β 3 Leu-Pro] (4b). 1 H NMR (500 MHz, 300 K, DMS-d 6 ) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-trp-β 3 Leu-β 3 Ala] (5). 1 H NMR (600 MHz, 300 K, DMS-d 6 ) δ (broad s, 1H), 7.89 (d, J = 6.9, 1H), 7.82 (d, J = 6.5, 1H), 7.52 (d, J = 7.8 Hz, 1H), 7.39 (d, J = 8.1, 1H), 7.35 (d, J = 7.9 Hz, 1H), 7.29 (d, J = 8.1 Hz, 1H), 7.03 (t, J = 7.9 Hz, 1H), 7.00 (m, J = 2.1 Hz, 1H), 6.96 (t, J = 7.8 Hz, 1H), 4.35 (m, 1H), 4.15 (m, 1H), 3.88 (m, 1H), 3.52 (m, 1H), 2.97 (m, 1H), 2.96 (m, 1H), 2.56 (m, 1H), 2.39 (q, J = 7.3, 2H), 2.36 (t, J = 7.3 Hz, 2H), 2.35 (m, 2H), 2.15 (m, 2H), 2.00 (m, 1H), 1.66 (m, 1H), 1.48 (m, 2H), 1.39 (m, 2H), 1.23 (m, 2H), 1.15 (m, 3H), 1.07 (m, 1H), 1.04 (d, J = 6.6 Hz, 3H), 0.91 (t, J = 7.3 Hz, 3H), 0.75 (d, J = 6.6 Hz, 3H), 0.71 (d, J = 6.6 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-β 3 Trp-β 3 Leu-Ala] (6). 1 H NMR (600 MHz, 323 K, DMS-d 6 ) δ (broad s, 1H), 7.92 (d, J = 5.4 Hz, 1H), 7.91 (d, J = 7.9 Hz, 1H), 7.54 (d, J = 6.8, 1H), 7.49 (d, J = 9.6, 1H), 7.33 (d, J = 8.1 Hz, 1H), 7.06 (m, 2H), 6.97 (t, J = 7.1, 1H), 6.88 (d, J = 8.8, 1H), 4.24 (m, 1H), 4.12 (m, 1H), 3.97 (m, 1H), 3.90 (m, 1H), 2.89 (m, 1H), 2.88 (m, 1H), 2.40 (q, J = 7.3, 2H), 2.37 (t, J = 7.4 Hz, 2H), 2.15 (m, 4H), 1.66 (m, 1H), 1.47 (m, 1H), 1.43 (m, 3H), (m, 5H), 1.21 (d, J = 7.3 Hz, 3H), 1.01 (m, 1H), 0.90 (t, J = 7.2 Hz, 3H), 0.83 (d, J = 6.5 Hz, 3H), 0.81 (d, J = 6.5 Hz, 3H). ESI-TF MS (m/z) found: [M+H] + ; calcld: c[aoda-β 3 Trp-β 3 Leu-Pro] (7). 1 H NMR (600 MHz, 300 K, DMS-d 6, mixture of isomers) spectrum is included below. ESI-TF MS (m/z) found: [M+H] + ; calcld: S6

7 Figure S1. NMR solution structures (DMS-d6) for selected peptides showing all side chain atoms. S7

8 RESY tables The atom labels used are those used by the program NEASY, and are illustrated in the chemical structure below. HQ refers to the β 3 proton. The # symbol represents an inability to differentiate two nearly equivalent or equivalent protons such as in the case with some C β protons or protons on side chains. Ambiguous protons were not used in the calculations. Compound 1. Proton Residue Proton Residue NE HB 4 AD HB 4 AD s HN 1 TRP HN 4 AD s HB 1 TRP HN 2 LEU s HQ # 1 TRP HA 1 TRP s HN 3 ALA HN 4 AD s HA 1 TRP HB 1 TRP s HB 4 AD HA 4 AD s HB 2 LEU HA 2 LEU s HB # 3 ALA HA 3 ALA s HB 2 LEU HN 2 LEU s HB 4 AD HA 4 AD s HB 2 LEU HG 2 LEU s HB 1 TRP HN 1 TRP s HB 2 LEU HA 2 LEU s HN 3 ALA HN 2 LEU s HG 2 LEU HN 2 LEU s HA 1 TRP HN 1 TRP s HB 4 AD HN 4 AD s HN 1 TRP HN 3 ALA s HA 2 LEU HN 2 LEU s HD1 1 TRP HE1 1 TRP s HA 4 AD HN 4 AD s HD2 # 2 LEU HA 2 LEU s HD1 # 2 LEU HG 2 LEU s HG 2 LEU HA 2 LEU s HD2 # 2 LEU HG 2 LEU s HB 4 AD HN 1 TRP m HA 1 TRP HB 1 TRP m HA 3 ALA HN 3 ALA m HB # 3 ALA HN 4 AD m HD1 # 2 LEU HB 2 LEU m HA 4 AD HN 1 TRP m HQ # 1 TRP HB 1 TRP m HB 2 LEU HN 3 ALA m HB # 3 ALA HN 3 ALA m HD2 # 2 LEU HB 2 LEU m HA 2 LEU HN 3 ALA m HZ2 1 TRP HE1 1 TRP m HB 4 AD HN 1 TRP m HB 2 LEU HN 2 LEU m HD1 # 2 LEU HB 2 LEU m HB 2 LEU HN 3 ALA m HQ # 1 TRP HB 1 TRP m HG # 4 AD HN 4 AD m HA 3 ALA HN 4 AD m HD1 # 2 LEU HA 2 LEU m HB 4 AD HN 4 AD m HN 1 TRP HN 2 LEU m HD2 # 2 LEU HB 2 LEU w HQ # 1 TRP HN 1 TRP w HD2 HG HD1 HZ3 HN HE3 HB HB HH2 HQ HA HA HZ2 HN N H HD1 NH HA HE1 HA HB NH HG HB HE HD HF HZ HY S8

9 Compound 2. Proton Residue Proton Residue NE HB 1 TRP HB 1 TRP s HN 3 ALA HN 2 LEU s HB 1 TRP HA 1 TRP s HB 1 TRP HA 1 TRP s HQ # 3 ALA HA 3 ALA s HQ # 3 ALA HN 4 AD s HD1 1 TRP HE1 1 TRP s HB # 3 ALA HA 3 ALA s HA 4 AD HB 4 AD s HA 4 AD HB 4 AD s HB 1 TRP HN 2 LEU s HA 1 TRP HD1 1 TRP s HN 1 TRP HN 2 LEU s HB 1 TRP HN 2 LEU s HA 2 LEU HB # 2 LEU s HA 1 TRP HE3 1 TRP s HA 3 ALA HN 3 ALA s HN 4 AD HB 4 AD s HF # 4 AD HE # 4 AD s HA 2 LEU HG 2 LEU s HA 2 LEU HN 2 LEU s HA 4 AD HN 4 AD s HQ # 3 ALA HN 3 ALA s HA 1 TRP HN 1 TRP s HB 1 TRP HE3 1 TRP s HB 2 LEU HN 3 ALA s HD # 2 LEU HA 2 LEU m HB 1 TRP HE3 1 TRP m HB 1 TRP HD1 1 TRP m HB 1 TRP HN 1 TRP m HN 1 TRP HN 4 AD m HN 2 LEU HG 2 LEU m HN 4 AD HB 4 AD m HN 3 ALA HN 1 TRP m HA 4 AD HC 4 AD m HZ2 1 TRP HE1 1 TRP m HN 2 LEU HB # 2 LEU m HB 1 TRP HN 1 TRP m HN 4 AD HC 4 AD m HD # 2 LEU HG 2 LEU m HA 2 LEU HN 3 ALA m HA 4 AD HN 1 TRP m HD # 2 LEU HA 2 LEU m HN 1 TRP HB 4 AD m HB # 3 ALA HN 3 ALA m HA 1 TRP HN 2 LEU m HI # 4 AD HH # 4 AD w HN 3 ALA HN 4 AD w HN 4 AD HC 4 AD w HN 1 TRP HB 4 AD w S9

10 Compound 3. Proton Residue Proton Residue NE HB 1 TRP HB 1 TRP s HB 3 ALA HA 3 ALA s HQ 2 LEU HA 2 LEU s HQ 2 LEU HN 3 ALA s HB 1 TRP HA 1 TRP s HB 1 TRP HA 1 TRP s HB 2 LEU HA 2 LEU s HB 2 LEU HA 2 LEU s HB 4 AD HN 1 TRP s HA 4 AD HB 4 AD s HN 2 LEU HN 1 TRP s HA 4 AD HB 4 AD s HA 2 LEU HN 2 LEU s HA 4 AD HC 4 AD s HN 4 AD HN 1 TRP s HQ 2 LEU HN 2 LEU s HB 4 AD HN 4 AD s HHD # 2 LEU HA 2 LEU s HA 1 TRP HE3 1 TRP s HA 3 ALA HN 3 ALA s HN 4 AD HN 3 ALA s HB 1 TRP HE3 1 TRP s HB 1 TRP HE3 1 TRP s HA 4 AD HN 4 AD m HG 2 LEU HA 2 LEU m HB 1 TRP HN 1 TRP m HB # 3 ALA HN 3 ALA m HA 1 TRP HN 1 TRP m HB 3 ALA HN 4 AD m HB 4 AD HE3 1 TRP m HA 1 TRP HN 2 LEU m HB 1 TRP HN 2 LEU m HB 2 LEU HD1 1 TRP m HA 4 AD HD # 4 AD m HC 4 AD HA 3 ALA m HB 3 ALA HA 4 AD m HA 4 AD HD # 4 AD m HA 4 AD HE3 1 TRP m HN 2 LEU HN 4 AD m HB 2 LEU HN 2 LEU m HG 2 LEU HD1 1 TRP m HA 3 ALA HN 4 AD m HB 1 TRP HN 2 LEU m HC 4 AD HD1 1 TRP w HB 1 TRP HN 1 TRP w HB 2 LEU HN 2 LEU w HA 4 AD HN 1 TRP w S10

11 Compound 3i. Proton Residue Proton Residue NE HB 1 TRP HB 1 TRP s HA 1 TRP HA 4 AD s HQ 2 LEU HA 2 LEU s HQ 2 LEU HN 3 ALA s HB 1 TRP HE3 1 TRP s HN 3 ALA HN 4 AD s HD # 2 LEU HG 2 LEU s HB # 3 ALA HA 3 ALA s HA 1 TRP HE3 1 TRP s HN 2 LEU HN 4 AD s HB # 2 LEU HA 2 LEU s HA 1 TRP HN 2 LEU m HA 2 LEU HN 2 LEU m HQ 2 LEU HN 2 LEU m HB 1 TRP HD1 1 TRP m HA 3 ALA HN 3 ALA m HD1 1 TRP HE1 1 TRP m HD # 2 LEU HA 2 LEU m HA 4 AD HN 4 AD m HC # 4 AD HA 4 AD m HN 4 AD HA 1 TRP m HB 4 AD HA 4 AD m HG 2 LEU HA 2 LEU m HB # 2 LEU HG 2 LEU m HQ 2 LEU HA 3 ALA m HM # 1 TRP HN 2 LEU m HM # 1 TRP HD1 1 TRP m HE # 4 AD HF # 4 AD m HB # 3 ALA HN 3 ALA m HB # 2 LEU HN 2 LEU m HA 1 TRP HD1 1 TRP m HB 1 TRP HE3 1 TRP m HQ 2 LEU HA 2 LEU m HB 4 AD HN 4 AD m HN 4 AD HA 3 ALA m HB # 2 LEU HQ 2 LEU m HZ2 1 TRP HE1 1 TRP m HC # 4 AD HA 3 ALA m HB 1 TRP HD1 1 TRP w HI # 4 AD HH # 4 AD w HD # 4 AD HF # 4 AD w HM # 1 TRP HE3 1 TRP w HG 2 LEU HM # 1 TRP w HB # 3 ALA HN 4 AD w HM # 1 TRP HA 1 TRP w HC # 4 AD HN 4 AD w HN 2 LEU HN 3 ALA w S11

12 Compound 4. Proton Residue Proton Residue NE HD 3 PR HD 3 PR s HQ 2 LEU HQ 2 LEU s HB 3 PR HA 3 PR s HN 4 AD HN 1 TRP s HQ 2 LEU HD 3 PR s HQ 2 LEU HA 2 LEU s HA 1 TRP HB 1 TRP s HB 2 LEU HA 2 LEU s HA 1 TRP HB 1 TRP s HB 4 AD HA 4 AD s HB 4 AD HA 4 AD s HA 2 LEU HN 2 LEU s HQ 2 LEU HD 3 PR s HQ 2 LEU HN 2 LEU s HB 2 LEU HA 2 LEU s HQ 2 LEU HG 2 LEU s HB 1 TRP HE3 1 TRP s HC # 3 PR HD 3 PR m HQ 2 LEU HB 2 LEU m HQ 2 LEU HD 3 PR m HB 1 TRP HN 2 LEU m HC # 3 PR HD 3 PR m HA 1 TRP HN 2 LEU m HB 3 PR HA 3 PR m HB 1 TRP HN 1 TRP m HD 3 PR HN 4 AD m HA 4 AD HN 4 AD m HC 4 AD HA 4 AD m HA 1 TRP HN 1 TRP m HE3 1 TRP HB 1 TRP m HE3 1 TRP HB 1 TRP m HA 1 TRP HE3 1 TRP m HB 4 AD HN 1 TRP m HB 4 AD HN 4 AD m HB 4 AD HN 4 AD m HB 2 LEU HQ 2 LEU m HB 4 AD HN 1 TRP m HB 2 LEU HQ 2 LEU m HE # 4 AD HF # 4 AD m HB 3 PR HD 3 PR m HA 2 LEU HD # 2 LEU m HB 3 PR HD 3 PR m HB 3 PR HN 4 AD m HC 3 PR HN 4 AD m HC # 3 PR HA 3 PR m HD 3 PR HA 3 PR m HA 2 LEU HD # 2 LEU m HA 3 PR HN 4 AD m HD1 1 TRP HE1 1 TRP w HI # 4 AD HH # 4 AD w HD # 4 AD HF # 4 AD w S12

13 Compound 5. Proton Residue Proton Residue NE HB 1 TRP HB 1 TRP s HQ 2 LEU HQ 2 LEU s HQ 3 ALA HQ 3 ALA s HB 2 LEU HB 2 LEU s HB 3 ALA HA 3 ALA s HQ 2 LEU HN 3 ALA s HQ 3 ALA HN 4 AD s HQ 3 ALA HA 3 ALA s HA 2 LEU HN 2 LEU s HA 1 TRP HN 2 LEU s HQ 2 LEU HA 2 LEU s HB 1 TRP HA 1 TRP s HQ 3 ALA HN 3 ALA s HB # 4 AD HA 4 AD s HB 1 TRP HA 1 TRP s HA 1 TRP HD1 1 TRP s HB 2 LEU HA 2 LEU s HA 1 TRP HN 1 TRP s HD # 2 LEU HG 2 LEU s HN 4 AD HN 1 TRP s HD1 1 TRP HE1 1 TRP s HA 3 ALA HN 3 ALA m HB 2 LEU HQ 2 LEU m HN 2 LEU HN 1 TRP m HG 2 LEU HB 2 LEU m HA 4 AD HN 4 AD m HB 2 LEU HA 2 LEU m HA 1 TRP HE3 1 TRP m HQ 2 LEU HN 2 LEU m HB 1 TRP HE3 1 TRP m HA 4 AD HN 1 TRP m HB # 4 AD HN 4 AD m HD # 2 LEU HA 2 LEU m HG 2 LEU HQ 2 LEU m HE # 4 AD HF # 4 AD m HB 2 LEU HQ 2 LEU m HB 1 TRP HE3 1 TRP m HA 4 AD HC 4 AD m HD # 2 LEU HG 2 LEU m HB 1 TRP HN 1 TRP m HD # 2 LEU HB 2 LEU m HG 2 LEU HD # 2 LEU m HG 2 LEU HD # 2 LEU m HB # 3 ALA HQ 3 ALA m HZ2 1 TRP HE1 1 TRP m HB 1 TRP HN 1 TRP m HG 2 LEU HA 2 LEU m HQ 3 ALA HA 3 ALA m HB 1 TRP HN 2 LEU m HB 1 TRP HD1 1 TRP m HB 2 LEU HD # 2 LEU m HB 1 TRP HN 2 LEU m HB # 3 ALA HQ 3 ALA m HB # 4 AD HN 1 TRP m HN 2 LEU HN 3 ALA m HG 2 LEU HN 2 LEU m HB 2 LEU HD # 2 LEU m HB 2 LEU HN 2 LEU w HB # 3 ALA HN 3 ALA w HQ 2 LEU HA 2 LEU w HB 2 LEU HQ 2 LEU w HI # 4 AD HH # 4 AD w HN 4 AD HN 3 ALA w HB 2 LEU HD # 2 LEU w HF # 4 AD HC 4 AD w HB 2 LEU HD # 2 LEU w HD # 2 LEU HN 2 LEU w HB 2 LEU HN 2 LEU w S13

14 Compound 6. Proton Residue Proton Residue NE HB 1 TRP HB 1 TRP s HB 4 AD HB 4 AD s HB 1 TRP HA 1 TRP s HQ # 2 LEU HN 2 LEU s HB 4 AD HA 4 AD s HQ # 2 LEU HN 3 ALA s HB # 3 ALA HA 3 ALA s HB 1 TRP HA 1 TRP s HB 2 LEU HA 2 LEU s HQ # 2 LEU HA 2 LEU s HA 1 TRP HN 1 TRP s HQ # 1 TRP HA 1 TRP s HD # 2 LEU HG 2 LEU s HA 4 AD HN 4 AD s HB 4 AD HA 4 AD s HA 1 TRP HE3 1 TRP s HB 1 TRP HD1 1 TRP s HB 2 LEU HA 2 LEU s HB 1 TRP HE3 1 TRP s HA 2 LEU HN 2 LEU s HD1 1 TRP HE1 1 TRP s HN 4 AD HN 3 ALA m HD # 2 LEU HA 2 LEU m HA 3 ALA HN 3 ALA m HA 4 AD HN 1 TRP m HQ # 1 TRP HN 1 TRP m HA 3 ALA HN 4 AD m HB 4 AD HN 1 TRP m HB 1 TRP HE3 1 TRP m HB 2 LEU HN 2 LEU m HB 4 AD HN 4 AD m HB 2 LEU HQ # 2 LEU m HE # 4 AD HF # 4 AD m HB # 3 ALA HN 3 ALA m HD # 2 LEU HB 2 LEU m HD # 4 AD HF # 4 AD m HN 2 LEU HN 1 TRP m HD # 2 LEU HB 2 LEU m HQ # 1 TRP HB 1 TRP m HG 2 LEU HA 2 LEU m HG 2 LEU HQ # 2 LEU m HQ # 1 TRP HE3 1 TRP m HB 4 AD HN 1 TRP m HB 2 LEU HQ # 2 LEU m HB 1 TRP HD1 1 TRP m HZ2 1 TRP HE1 1 TRP m HB 1 TRP HN 1 TRP m HQ # 1 TRP HB 1 TRP m HB 4 AD HE3 1 TRP w HG 2 LEU HN 2 LEU w HI # 4 AD HH # 4 AD w HB 4 AD HN 4 AD w HA 2 LEU HE3 1 TRP w HN 2 LEU HN 4 AD w S14

15 1 H NMR spectra Peptide 3b S15

16 S16

17 Peptide 3e S17

18 S18

19 Peptide 7 Complete bibliographic information for reference 11a: 11 (a). Somoza, J. R.; Skene, R. J.; Katz, B. A.; Mol, C.; Ho, J. D.; Jennings, A. J.; Luong, C.; Arvai, A.; Buggy, J. J.; Chi, E.; Tang, J.; Sang, B.-C.; Verner, E.; Wynands, R.; Leahy, E. M.; Dougan, D. R.; Snell, G.; Navre, M.; Knuth, M. W.; Swanson, R. V.; McRee, D. E.; Tari, L. W. Structure 2004, 12, S19