1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000 0.00000 0.00000 0.00000 Zhang, J.Y. Hong, M. http://mmcif.pdb.org/dictionaries/ascii/mmcif_pdbx.dic C3 H7 N O2 89.093 y ALANINE L-peptide linking C6 H13 N O2 131.173 y LEUCINE L-peptide linking C6 H15 N2 O2 1 147.195 y LYSINE L-peptide linking C5 H11 N O2 117.146 y VALINE L-peptide linking N 1 N N N 2 S C N 3 N C N 4 N O N 5 N C N 6 N O N 7 N H N 8 N H N 9 N H N 10 N H N 11 N H N 12 N H N 13 N H N 14 N N N 15 S C N 16 N C N 17 N O N 18 N C N 19 N C N 20 N C N 21 N C N 22 N O N 23 N H N 24 N H N 25 N H N 26 N H N 27 N H N 28 N H N 29 N H N 30 N H N 31 N H N 32 N H N 33 N H N 34 N H N 35 N H N 36 N N N 37 S C N 38 N C N 39 N O N 40 N C N 41 N C N 42 N C N 43 N C N 44 N N N 45 N O N 46 N H N 47 N H N 48 N H N 49 N H N 50 N H N 51 N H N 52 N H N 53 N H N 54 N H N 55 N H N 56 N H N 57 N H N 58 N H N 59 N H N 60 N H N 61 N N N 62 S C N 63 N C N 64 N O N 65 N C N 66 N C N 67 N C N 68 N O N 69 N H N 70 N H N 71 N H N 72 N H N 73 N H N 74 N H N 75 N H N 76 N H N 77 N H N 78 N H N 79 N H N 1 N sing N 2 N sing N 3 N sing N 4 N sing N 5 N sing N 6 N sing N 7 N doub N 8 N sing N 9 N sing N 10 N sing N 11 N sing N 12 N sing N 13 N sing N 14 N sing N 15 N sing N 16 N sing N 17 N sing N 18 N sing N 19 N doub N 20 N sing N 21 N sing N 22 N sing N 23 N sing N 24 N sing N 25 N sing N 26 N sing N 27 N sing N 28 N sing N 29 N sing N 30 N sing N 31 N sing N 32 N sing N 33 N sing N 34 N sing N 35 N sing N 36 N sing N 37 N sing N 38 N sing N 39 N sing N 40 N doub N 41 N sing N 42 N sing N 43 N sing N 44 N sing N 45 N sing N 46 N sing N 47 N sing N 48 N sing N 49 N sing N 50 N sing N 51 N sing N 52 N sing N 53 N sing N 54 N sing N 55 N sing N 56 N sing N 57 N sing N 58 N sing N 59 N sing N 60 N sing N 61 N sing N 62 N sing N 63 N sing N 64 N doub N 65 N sing N 66 N sing N 67 N sing N 68 N sing N 69 N sing N 70 N sing N 71 N sing N 72 N sing N 73 N sing N 74 N sing N 75 N sing US Proc.Natl.Acad.Sci.USA PNASA6 0040 1091-6490 123 e2618039123 e2618039123 10.1073/pnas.2618039123 42696554 Peptides adopt stable omega-loop structures in concentrated sulfuric acid. 2026 0000-0002-1921-4848 0000-0002-6892-6948 0000-0001-5255-5858 10.2210/pdb12ui/pdb pdb_000012ui 10.13018/BMR31304 743.977 K7 peptide 1 syn polymer no no AKLLKAV AKLLKAV A polypeptide(L) n n n n n n n repository Initial release 1 0 2026-09-16 United States Other private G-2023-20929 meihong@mit.edu 0000-0001-5255-5858 Mei Hong principal investigator/group leader Same primary citation Same primary citation K7 peptide structure in 98% H2SO4 N RCSB Y RCSB 2026-04-19 REL REL 32630 synthetic construct sample 1 7 N structures with the lowest energy 1000 20 isotropic 1 2D 1H-1H NOESY isotropic 1 2D 1H-13C HMQC isotropic 1 2D 1H-15N HSQC isotropic 1 3D HNHA 10.5 mg/mL natural abundance 98 % w/w natural abundance 1 mg/mL natural abundance 18.4 M conditions_1 0 pH 1 atm 293 K na 1 lowest energy 10.5 mg/mL K7 peptide, 98 % w/w H2SO4, 1 mg/mL dimethyl sulfone, 98% H2SO4/2% H2O NA_sample 98% H2SO4/2% H2O solution Schwieters, Kuszewski, Tjandra and Clore structure calculation X-PLOR NIH CCPN chemical shift assignment CcpNmr Analysis 800 Bruker AVANCE III ALA 1 n 1 ALA 1 A LYS 2 n 2 LYS 2 A LEU 3 n 3 LEU 3 A LEU 4 n 4 LEU 4 A LYS 5 n 5 LYS 5 A ALA 6 n 6 ALA 6 A VAL 7 n 7 VAL 7 A author_and_software_defined_assembly 1 monomeric not applicable NMR Distance Restraints 1.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 1.0 1_555 x,y,z identity operation 0.0 0.0 0.0 1 A LYS 2 -169.82 54.79 1 A LEU 3 29.96 39.12 1 A LEU 4 35.25 41.69 1 A ALA 6 -61.87 87.58 2 A LYS 2 -169.76 54.68 2 A LEU 3 29.93 38.93 2 A LEU 4 35.98 41.59 2 A ALA 6 -63.73 86.82 3 A LYS 2 30.23 54.14 3 A LEU 3 29.40 40.48 3 A LEU 4 34.84 41.54 3 A ALA 6 -62.17 92.14 4 A LYS 2 30.14 54.00 4 A LEU 3 29.38 40.45 4 A LEU 4 35.00 41.62 4 A ALA 6 -62.16 92.18 5 A LYS 2 30.15 54.09 5 A LEU 3 29.46 40.48 5 A LEU 4 34.91 41.52 5 A ALA 6 -62.19 92.03 6 A LYS 2 30.36 54.13 6 A LEU 3 30.21 38.99 6 A LEU 4 36.62 42.03 6 A ALA 6 -62.69 89.20 7 A LYS 2 32.20 54.30 7 A LEU 3 31.05 39.11 7 A LEU 4 35.93 43.19 7 A ALA 6 -64.39 86.35 8 A LYS 2 28.37 49.65 8 A LEU 3 30.05 37.96 8 A LEU 4 37.59 41.66 8 A LYS 5 -170.81 -176.64 8 A ALA 6 -62.26 95.01 9 A LYS 2 28.88 52.92 9 A LEU 3 27.67 52.67 9 A LEU 4 39.61 73.03 9 A LYS 5 99.82 -67.38 9 A ALA 6 -62.99 83.40 10 A LYS 2 28.92 52.96 10 A LEU 3 27.61 52.58 10 A LEU 4 39.87 72.97 10 A LYS 5 99.84 -67.51 10 A ALA 6 -62.99 83.61 11 A LYS 2 28.95 52.92 11 A LEU 3 27.68 52.66 11 A LEU 4 39.79 72.87 11 A LYS 5 99.82 -67.38 11 A ALA 6 -63.05 83.59 12 A LYS 2 89.00 59.76 12 A LEU 3 34.31 36.56 12 A LEU 4 36.94 44.08 12 A ALA 6 -64.00 86.44 13 A LYS 2 28.86 51.40 13 A LEU 3 30.59 64.29 13 A LEU 4 37.86 59.19 13 A LYS 5 98.36 -43.00 13 A ALA 6 -66.19 72.03 14 A LYS 2 33.46 55.61 14 A LEU 3 30.33 39.26 14 A LEU 4 92.08 64.38 14 A LYS 5 30.03 59.02 14 A ALA 6 -169.63 54.66 15 A LYS 2 28.93 53.02 15 A LEU 3 28.13 52.53 15 A LEU 4 38.79 70.50 15 A LYS 5 98.43 -52.67 15 A ALA 6 -65.74 71.65 16 A LYS 2 28.95 52.94 16 A LEU 3 28.18 52.57 16 A LEU 4 38.98 70.74 16 A LYS 5 98.39 -53.92 16 A ALA 6 -65.48 72.61 17 A LYS 2 28.98 53.36 17 A LEU 3 28.30 52.54 17 A LEU 4 39.26 71.74 17 A LYS 5 98.34 -56.98 17 A ALA 6 -64.86 76.27 18 A LYS 2 26.05 49.24 18 A LEU 3 29.83 60.96 18 A LEU 4 37.67 60.69 18 A LYS 5 100.58 -44.92 18 A ALA 6 -66.73 70.76 19 A LYS 2 29.48 49.77 19 A LEU 3 29.37 66.72 19 A LEU 4 41.65 84.25 19 A LYS 5 33.84 70.04 19 A ALA 6 -171.62 58.29 20 A LYS 2 29.57 50.02 20 A LEU 3 29.19 66.42 20 A LEU 4 41.66 84.41 20 A LYS 5 34.03 69.95 20 A ALA 6 -171.66 58.45 N NMR structure of K7 peptide in 98% H2SO4 1 N N DE NOVO PROTEIN protein folding, concentrated sulfuric acid, exoplanet, Venus cloud, DE NOVO PROTEIN 12UI PDB 1 1 12UI 1 7 12UI 1 7 12UI A 1 1 7