EFFECT OF VARIOUS GLYCOSIDASE TREATMENTS ON THE RESISTANCE OF THE HIV-1 ENVELOPE TO DEGRADATION

Using a CD4-binding assay to assess the conformation of the human immu nodeficiency virus envelope glycoprotein (CHO+ Env), we studied the ef fect of treatment with various glycosidases on the stability of Env in denaturing environments and in biological media: cleavage from Env of either high-mannose-type glycans(HMT(-) Env) by endoglycosidase H or sialic acid residues (Sial(-) Env) by sialidase did not alter Env stab ility whereas its complete deglycosylation (CHO- Env) by N-glycanase h ad a large effect. The influence of glycan removal on Env sensitivity to proteases was also studied. Thrombin cleavage within V3 was affecte d by N-glycanase treatment; both HMT(-) Env and CHO- Env displayed an increased sensitivity to other endoproteases. Thus, partial deglycosyl ation increases Env sensitivity to proteases but only its total deglyc osylation alters its stability. (C) 1997 Federation of European Bioche mical Societies.