Use of hydrophobic moment plot methodology to aid the identification of oblique orientated α-helices

Abstract

A number of α-helix forming peptides have been reported which appear to promote membrane fusion and other biological events related to the disruption of a hydrophobic/hydrophilic interface, due to the presence of a hydrophobicity gradient along the helical long axis. When α-helices from this class were analysed according to hydrophobic moment plot methodology a linear association was found to exist between the mean hydrophobic moment, 〈μH〉, and the corresponding mean hydrophobicity, 〈H0〉. This association was described by the least squares regression line: 〈μH〉=0.508-0.422 〈H0〉 and, here, a methodology to aid the prediction of oblique orientated α-helices is presented, based on a 99% prediction band around this regression line. This methodology is intended to provide an initial identification of candidates for further investigation by other techniques such as the molecular hydrophobic potential and laboratory based experimentation, not to assign function.