title: The crystal structure of Z-Gly-Aib-Gly-Aib-OtBu.
abstract: The synthetic peptide Z-Gly-Aib-Gly-Aib-OtBu was dissolved in methanol and crystallized in a mixture of ethyl acetate and petroleum ether. The crystals belong to the centrosymmetric space group P4/n that is observed less than 0.3% in the Cambridge Structural Database. The first Gly residue assumes a semi-extended conformation (φ ±62°, ψ ∓131°). The right-handed peptide folds in two consecutive β-turns of type II' and type I or an incipient 310 -helix, and the left-handed counterpart folds accordingly in the opposite configuration. In the crystal lattice, one molecule is linked to four neighbors in the ab-plane via hydrogen bonds. These bonds form a continuous network of left- and right-handed molecules. The successive ab-planes stack via apolar contacts in the c-direction. An ethyl acetate molecule is situated on and close to the fourfold axis.
authors.affiliation: IMBB, FORTH, 70013, Heraklion, Greece.
authors.forename: Renate
authors.initials: R
authors.lastname: Gessmann
authors.affiliation: Department of Food Sciences, Interdisciplinary Research Center, Justus-Liebig-University of Giessen, 35392, Giessen, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Brückner
authors.affiliation: IMBB, FORTH, 70013, Heraklion, Greece.
authors.forename: Michalis
authors.initials: M
authors.lastname: Aivaliotis
authors.affiliation: IMBB, FORTH, 70013, Heraklion, Greece.
authors.forename: Kyriacos
authors.initials: K
authors.lastname: Petratos
mesh_terms: D000085:Acetates / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D002606:Charcoal / Q000737:chemistry; D006860:Hydrogen Bonding; D000432:Methanol / Q000737:chemistry; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D000085:Acetates; D000473:Alkanes; D010455:Peptides; D002606:Charcoal; C007650:ethyl acetate; C004544:naphtha; D000432:Methanol
keywords: Gly-Aib peptides; achiral peptides; centrosymmetry; crystal structure; semi-extended conformation; α-aminoisobutyric acid