Biopolymers 2002-04-15

Analysis of peptide rotational diffusion by homonuclear NMR.

Thérèse E Malliavin, Emmanuel Giudice

Index: Biopolymers 63(5) , 335-42, (2002)

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Abstract

The analysis of the rotational diffusion of a molecule using homonuclear NMR is investigated. The homonuclear longitudinal and transverse cross-relaxation rates, which can be quantitatively measured using off-Resonance Rotating frame nuclear Overhauser Effect Spectroscopy (ROESY), are used to build a distribution, which exhibits a solid-state-like pattern characteristic of the diffusion tensor. The distributions of the antimicrobial peptide ranalexin in water and in 30% of trifluoracetic acid (TFE) are compared, and the peptide rotational diffusion is shown to be more isotropic in water than in 30% TFE. This difference is further supported by the analysis of NMR ranalexin conformers in 30% TFE, and by the analysis of a molecular dynamics simulation of peptide in water.Copyright 2002 Wiley Periodicals, Inc.