THE MOST HIGHLY AMPHIPHILIC ALPHA-HELICES INCLUDE 2 AMINO-ACID SEGMENTS IN HUMAN-IMMUNODEFICIENCY-VIRUS GLYCOPROTEIN-41

A search for highly amphiphilic α‐helices has been made in a data base of protein sequences, using the helical hydrophobic moment as a criterion of amphiphilicity. The protein segments of largest hydrophobic moment have been analyzed. For the segments whose structures are known, they are in fact α‐helices. Two of the segments having very large hydrophobic moments are from the smaller C‐terminal portion of the human immunodeficiency virus (HIV) envelope glycoprotein gp41. Also, among segments having large hydrophobic moments, but not among the most extreme, are lytic peptides such as melittin. Melittin seeks surfaces between polar and apolar phases, including the membrane–water interface. It is conceivable that the gp41 segments of extreme hydrophobic moment may participate in one of the membrane‐related functions of the HIV virus. Copyright © 1990 John Wiley & Sons, Inc.