title: Pyrrolidine ring puckering in cis and trans-proline residues in proteins and polypeptides. Different puckers are favoured in certain situations.
abstract: In a set of proteins studied at high resolution by X-ray crystallography over a half of all cis and trans-proline residues could be unambiguously assigned to one of the two forms of pyrrolidine ring puckering, called UP and DOWN. Of these, 89% of the cis-proline residues exhibit the DOWN pucker, while the trans-proline residues, on average, are about evenly distributed between the two forms. Of trans-proline residues found in alpha-helices, 79% have the UP ring pucker. trans-proline residues occurring in other situations are more equally distributed between the two forms of pucker, although further generalizations may be possible. Proline residues in a set of crystal structures of short polypeptides were also examined. As in the protein sample, a tendency for the cis-proline residues to have the DOWN pucker was observed, but the effect was less pronounced.
authors: Department of Biochemistry, University of Glasgow, Scotland, U.K.
authors: E J
authors: EJ
authors: Milner-White
authors: L H
authors: LH
authors: Bell
authors: P H
authors: PH
authors: Maccallum
mesh_terms: D000595:Amino Acid Sequence; D016208:Databases, Factual; D007536:Isomerism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D010455:Peptides; D011506:Proteins; D011392:Proline