Comments on the use of a dichromophoric circular dichroism assay for the identification of beta-turns in peptides.
Use of the dichromophoric CD assay for beta-turn formation in peptide sequences has been investigated. The assay involves the observation of Cotton effects in CD spectra, originating from the approach of N- and C-terminal aromatic chromophores in tetrapeptides. The approach of the chromophores was believed to be brought about by a beta-turn in the peptide structure. Our investigations were paralleled by NMR studies which revealed the presence of a previously unreported hydrogen bond in the beta-turn conformers, which appears to play a role in the generation of the observed Cotton effects. This suggests caution in the use of the CD technique alone as an assay for beta-turn conformers in peptides.
Baldwin
J E
JE
Dyson Perrins Laboratory, Oxford, UK.
Claridge
T D
TD
Hulme
C
C
Rodger
A
A
Schofield
C J
CJ
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary
D010455:Peptides