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Three complete turns of a 3 10 ‐helix at atomic resolution: the crystal structure of Z‐(Aib) 11 ‐O t Bu
Author(s) -
Gessmann Renate,
Brückner Hans,
Petratos Kyriacos
Publication year - 2003
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.490
Subject(s) - crystallography , crystal structure , antiparallel (mathematics) , chemistry , hydrogen bond , molecule , crystal (programming language) , helix (gastropod) , solvent , resolution (logic) , stereochemistry , physics , ecology , organic chemistry , quantum mechanics , snail , magnetic field , computer science , programming language , biology , artificial intelligence
The crystal structure of the synthetic protected oligopeptide Z‐(Aib) 11 ‐O t Bu was determined by x‐ray crystallography. The undecapeptide folds in a regular 3 10 ‐helix with nine consecutive 4 → 1 hydrogen bonds. At present, this is the largest available structure of a homopeptide (including homopeptides consisting of standard amino acids) and also the longest observed regular 3 10 ‐helix at atomic resolution. Z‐(Aib) 11 ‐O t Bu crystallizes readily from hot ethanol–water mixture and is one of the crystals in which no solvent molecule is co‐crystallized. In the crystal head‐to‐tail hydrogen bonded columns are formed in the [ 1 0 1 ] direction. Each helical column is surrounded by six others, whereby two are packed in parallel and four in antiparallel fashion. Helical columns are packed via apolar crystal contacts. The crystal structure of Z‐(Aib) 11 ‐O t Bu is compared with the crystal structures of Z‐(Aib) 10 ‐O t Bu and Z‐(Aib) 9 ‐O t Bu. The similarities and differences are analysed. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.