The concept of effective correlation times for describing backbone motions in proteins. Part II. Tentative interpretation of the residue-specific correlation time in terms of overall rotation-diffusion

✍ Scribed by Sabine Bouguet-Bonnet; Pierre Mutzenhardt; Christian Roumestand; Daniel Canet

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 202 KB
• Volume: 24A
• Category: Article
• ISSN: 1546-6086
• DOI: 10.1002/cmr.a.20027

✦ Synopsis

Abstract

In part I of this article, it was shown that protein ^15^N relaxation data at different magnetic fields can be fitted according to a residue‐specific correlation time τ~eff~, which is associated with slow motions sensed by the considered residue. The present article is an attempt to justify the correlation time variations along the backbone by anisotropic overall motion. When an axial rotation‐diffusion tensor is assumed, it is possible to derive simple expressions for relating τ~eff~ to τ~⟂~ and τ~//~ (the two correlation times defining the rotation‐diffusion tensor). A consistent picture is obtained for the most organized parts of the protein C12A‐p8^MTCP1^ which, as in part I of this article, serves here as an example. By contrast, the model of rotation‐diffusion fails for other less‐organized parts of the protein, suggesting a combination of several slow or intermediate motions. © 2005 Wiley Periodicals, Inc. Concepts Magn Reson Part A 24A: 10–16, 2005.