Novel disulfide-constrained pentapeptides as models for beta-VIa turns in proteins.
The conformational behavior of cyclic peptides of the amino acid sequence Cys-Phe/Ala-Pro-Ala-Cys has been investigated through the combined use of molecular simulation methods and NMR experiments to find models for beta-VIa turns of proteins. Both oxidized (cyclic) peptides and reduced (linear) forms were investigated. At least 95% of the cyclic peptides show a cis conformation of the Xaa-Pro bond in solution in DMSO or water, whereas all other peptide bonds are trans. Furthermore, we observed a hydrogen bond between the NH group of residue Ala4 and the C = O group of residue Cys1. Both properties are indicative of beta-VIa turns. After reduction of the disulfide bridge, the all-trans form of the peptide bonds predominates.
Weisshoff
H
H
Humboldt University Berlin, Institute of Chemistry, Germany.
Frost
K
K
Brandt
W
W
Henklein
P
P
Mügge
C
C
Frömmel
C
C
D001483:Base Sequence; D004220:Disulfides; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation
D004220:Disulfides; D010455:Peptides