title: N-(tert-butoxycarbonyl)-L-valyl-L-valine methyl ester: a twisted parallel β-sheet in the crystal structure of a protected dipeptide.
abstract: The title compound, C(16)H(30)N(2)O(5), crystallizes with three molecules in the asymmetric unit, each adopting a β-strand/polyproline II backbone conformation. The main-chain functional groups are hydrogen bonded into tapes having the characteristics of parallel β-sheets. Each tape has a left-handed twist and thus forms a helix, with six peptide molecules needed to complete a full 360° rotation. A comparison of hydrogen-bond lengths and twisting modes is made with other related structures of protected dipeptides and with a hexapeptide derived from amyloid-β containing the Val-Val segment. Additionally, a comparison of the backbone conformation is made with that of the Val141-Val142 segment of the water channel aquaporin-4 (AQP4).
authors.affiliation: School of Pharmacy, University of Oslo, Oslo, Norway.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Jacobsen
authors.forename: Hadgu Girmay
authors.initials: HG
authors.lastname: Gebreslasie
authors.forename: Jo
authors.initials: J
authors.lastname: Klaveness
authors.forename: Pål
authors.initials: P
authors.lastname: Rongved
authors.forename: Carl Henrik
authors.initials: CH
authors.lastname: Görbitz
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D017433:Protein Structure, Secondary; D013237:Stereoisomerism
chemical_list: D000682:Amyloid; D004151:Dipeptides; C561503:N-(tert-butoxycarbonyl)-L-valyl-L-valine methyl ester