Investigating the conformational coupling between the transmembrane and cytoplasmic domains of a single-spanning membrane protein - A H-1-NMR study

PMP1 is a 38-residue single-spanning membrane protein whose C-terminal cyto plasmic domain, Y25-F38, is highly positively charged. The conformational c oupling between the transmembrane span and the cytoplasmic domain of PMP1 w as investigated from H-1-nuclear magnetic resonance data of two synthetic f ragments: F9-F38, i.e. 80% of the whole sequence, and Y25-F38, the isolated cytoplasmic domain. Highly disordered in aqueous solution, the Y25-F38 pep tide adopts a well-defined conformation in the presence of dodecylphosphoch oline micelles. Compared with the long PMP1 fragment, this structure exhibi ts both native and non-native elements. Our results make it possible to ass ess the influence of a hydrophobic anchor on the intrinsic conformational p ropensity of a cytoplasmic domain. (C) 2001 Federation of European Biochemi cal Societies. Published by Elsevier Science B.V. All rights reserved.