title: Pearls on a string: a Z' = 7 structure for glycyl-L-valine.
abstract: The title peptide, C7H14N2O3, crystallizes with seven independent molecules in the asymmetric unit. All have essentially the same overall conformation, but some flexibility is exhibited by the glycine residue. It appears that the high Z' value, observed only three times before for an organic compound, permits formation of shorter hydrogen bonds in one of the two head-to-tail chains involving the N-terminal amino groups and the C-terminal carboxylate groups than found in a hypothetical model structure of glycyl-L-valine with Z' = 1, and that it furthermore alleviates strain associated with an eclipsed orientation of the amino group.
authors.affiliation: Department of Chemistry, University of Oslo, PO Box 1033 Blindern, N-0315 Oslo, Norway. c.h.gorbitz@kjemi.uio.no
authors.forename: Carl Henrik
authors.initials: CH
authors.lastname: Görbitz
authors.forename: Silja
authors.initials: S
authors.lastname: Agustsdottir
authors.forename: Francesca
authors.initials: F
authors.lastname: Bleken
mesh_terms: D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D011336:Probability
chemical_list: D004151:Dipeptides; C035810:glycylvaline