ON THE ROLE OF CD4 CONFORMATIONAL CHANGE IN THE HIV-CELL FUSION PROCESS

It is well Known that the gp120-gp41 complex undergoes a conformationa l change after CD4 binding It is likely that CD4 undergoes a conformat ional change as well. Recently, a calculation of the normal modes of t he two N-terminal domains of CD4 has shown that a hinge-bending motion of one of these domains with respect to the other may occur In the pr esent study, results obtained previously are verified with two other n ormal mode calculations, starting from crystallographic structures of different origin. A scheme describing the first steps of the process l eading to cell infection by human immunodeficiency virus (HIV) is then proposed. It rests upon the idea that CD4 and gp120-gp41 conformation al changes allow for bringing the cell and virus membranes closer to e ach other.