This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.108.134858v1 95/2/L22    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by McConnell, H. Articles by Radhakrishnan, A. PubMed PubMed Citation Articles by McConnell, H. Articles by Radhakrishnan, A.

Molecular Motion at the Critical Point in Lipid Membranes

Harden McConnell ^* and Arun Radhakrishnan 

^* Department of Chemistry, Stanford University, Stanford, California; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas

Correspondence: Address reprint requests and inquiries to Harden McConnell, Tel.: 650-723-4571; E-mail: harden{at}stanford.edu; or Arun Radhakrishnan, Tel: 214-648-7166; E-mail: arun314{at}yahoo.com.

It is shown that the calculated temperature dependence of the deuterium nuclear magnetic resonance (NMR) of labeled cholesterol-phospholipid bilayers is changed by magic-angle spinning. This makes it possible to distinguish different molecular motions at temperatures near a miscibility critical point, for motions with distinct temperature-dependent correlation times. In this way one finds that NMR line broadening due to critical point composition fluctuations can be distinguished from broadening due to the formation and dissociation of complexes.