A conformational preference parameter to predict helices in integral membrane proteins.

Assignments were made for helical regions in several integral membrane proteins using an algorithm devised to delineate the transmembrane helices in bacteriorhodopsin (Eur. J. Biochem. 182 (1982) 565-575). A new conformational preference parameter for membrane-buried helices was obtained. The use of this parameter to predict helices in membrane proteins is discussed. When applied to the L and M subunits of Rhodopseudomonas sphaeroides, five helices were predicted, which is consistent with the three-dimensional X-ray crystal structure. Data on signal sequences and amino acid exchanges in membrane proteins are also analysed and discussed