Structures of dipeptides: the head-to-tail story.
The hydrogen-bonding patterns in crystal structures of unprotected, zwitterionic dipeptides are dominated by head-to-tail chains involving the N-terminal amino groups and the C-terminal carboxylate groups. Patterns that include two concomitant chains, thus generating a hydrogen-bonded layer, are of special interest. A comprehensive survey shows that dipeptide structures can conveniently be divided into only four distinct patterns, differing by definition in the symmetry of the head-to-tail chains and amide hydrogen-bonding type, but also in other properties such as peptide conformation and the propensity to include solvent water or various organic guest molecules. Upon crystallization, the choice of pattern for a specific dipeptide is not random, but follows from the amino acid sequence.
Görbitz
Carl Henrik
CH
Department of Chemistry, University of Oslo, Norway. c.h.gorbitz@kjemi.uio.no
D000595:Amino Acid Sequence; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D011487:Protein Conformation; D013237:Stereoisomerism
D004151:Dipeptides