SECONDARY STRUCTURE OF GP160 AND GP120 ENVELOPE GLYCOPROTEINS OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 - A FOURIER-TRANSFORM INFRARED SPECTROSCOPIC STUDY

The secondary structure of the precursor (gp160) of the envelope prote in of human immunodeficiency virus type 1 (BH10) and its receptor-bind ing subunit (gp120) was studied by Fourier-transformed attenuated tota l reflection spectroscopy. A higher alpha-helix/beta-sheet ratio in th e gp120 subunit than in the precursor indicates a structural heterogen eity between the two subunits (gp120 and gp41), in agreement with clas sical secondary-structure predictions. The secondary structure of gp41 was estimated and compared with existing models. The high alpha-helic al content in gp41 and the dominant beta-sheet content in gp120 resemb le the distribution in influenza virus hemagglutinin subunits.