Structure of coat proteins in Pf1 and fd virions by laser raman spectroscopy.

Rama spectra of filamentous bacterial viruses are dominated by scattering from vibrations of the protein capsomers. The amino acid compositions of coat proteins in Pfl and fd strains are recognized by their different side-chain vibrational frequencies. However, the conformationally sensitive amide frequencies indicate that Pfl and fd coat proteins have the same alpha-helicial secondary structures. Viral DNA backbones do not exhibit the A-type geometry.