β-Sheet and associated turn signatures in vibrational Raman optical activity spectra of proteins

✍ Scribed by Z. Q. Wen; L. Hecht; L. D. Barron

• Book ID: 105356200
• Publisher: Cold Spring Harbor Laboratory Press
• Year: 2008
• Tongue: English
• Weight: 471 KB
• Volume: 3
• Category: Article
• ISSN: 0961-8368
• DOI: 10.1002/pro.5560030308

✦ Synopsis

Abstract

We have measured the aqueous solution vibrational Raman optical activity (ROA) spectra of concanavalin A, α‐chymotrypsin, and β‐lactoglobulin, all of which are rich in β‐sheet, together with that of the model β‐turn peptide L‐pro‐L‐leu‐gly‐NH~2~. Possible ROA signatures of antiparallel β‐sheet include a strong sharp positive band at ∼ 1,313 cm” associated with backbone amide III C~α~H and NH deformations, and an amide I couplet, negative at low wavenumber and positive at high, centered at ∼1,658 cm^−1^. Negative ROA bands in the range ∼1,340‐1,380 cm^−1^, which might originate in glycine CH~2~ deformations, appear to be characteristic of β‐turns. Our results provide further evidence that ROA is a more incisive probe of protein conformation than conventional vibrational spectroscopy, infrared, or Raman, because only those few vibrational coordinates within a given normal mode that sample the skeletal chirality directly contribute to the corresponding ROA band intensity.