Proline motifs in peptides and their biological processing.

摘要: Many biologically important peptide sequences contain proline. It confers unique conformational constraints on the chain in that side-chain is cyclized back onto backbone amide position. Inside an alpha-helix possibility of making hydrogen bonds to preceding turn lost and a kink will be introduced. The restrictions imposed by proline motifs appear imply structural or biological functions as can deduced from their often remarkably high degree conservation found many proteins peptides, especially cytokines, growth factors, G-protein-coupled receptors, V3 loops HIV envelope glycoprotein gp 120, neuro- vasoactive peptides. Only limited number peptidases are known able hydrolyze adjacent bonds. Their activity influenced isomeric state (cis-trans) well position chain. three specific metallo-peptidases (aminopeptidase P, carboxype...