Interpretation of energy-transfer experiments by theoretical studies of model compounds using semiempirical potential functions. I. Three-linked aromatic peptide units

✍ Scribed by R. Guillard; A. Englert

• Publisher: Wiley (John Wiley & Sons)
• Year: 1976
• Tongue: English
• Weight: 642 KB
• Volume: 15
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1976.360150707

✦ Synopsis

Abstract

It is shown that theoretical conformational analysis, based on the evaluation of semiempirical potential functions, can be used to compute the quantities relevant to the interpretation of energy‐transfer experiments. The relevant properties are computed for a segment of a polypeptide chain with the sequence Tyr‐Tyr. In particular, the average value of the orientation factor 〈κ^2^〉 and its distribution ƒ(κ^2^) are examined. It appears that the degrees of freedom for rotation of the side chains are not sufficient to randomize completely the orientation factor of the transition dipoles. Two additional degrees of freedom, namely the torsion angles around the valence bonds of the backbone, ψ~1~ and ϕ~2~, bring 〈κ^2^〉 close to the value that corresponds to randomly oriented transition dipoles.