Preferred proline puckerings in cis and trans peptide groups: implications for collagen stability.
The interplay between side-chain and main-chain conformations is a distinctive characteristic of proline residues. Here we report the results of a statistical analysis of proline conformations using a large protein database. In particular, we found that proline residues with the preceding peptide bond in the cis state preferentially adopt a down puckering. Indeed, out of 178 cis proline residues, as many as 145 (81%) are down. By analyzing the 1-4 and 1-5 nonbonding distances between backbone atoms, we provide a structural explanation for the observed trend. The observed correlation between proline puckering and peptide bond conformation suggests a new mechanism to explain the reported shift of the cis-trans equilibrium in proline derivatives. The implications of these results for the current models of collagen stability are also discussed.
Vitagliano
L
L
Centro di Studio di Biocristallografia, CNR, I-80134 Napoli, Italy. luigiv@chemistry.unina.it
Berisio
R
R
Mastrangelo
A
A
Mazzarella
L
L
Zagari
A
A
D000465:Algorithms; D003094:Collagen / Q000737:chemistry*; D006909:Hydroxyproline / Q000737:chemistry*; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation
D010455:Peptides; D003094:Collagen; D011392:Proline; D006909:Hydroxyproline