Characterization of gp41 as the Transmembrane Protein Coded by the HTLV-III/LAV Envelope Gene

Abstract

Radiolabeled amino acid sequencing was used to characterize gp41, an antigen of HTLV-III/LAV, the virus believed to be the etiological agent of the acquired immune deficiency syndrome. This antigen is the one most commonly detected in immunoblot assays by sera of patients with AIDS or AIDS-related complex (ARC) and other individuals infected with HTLV-III/LAV. A mouse monoclonal antibody that was reactive with gp41 precipitated a 160-kilodalton protein (gp160) in addition to gp41, but did not precipitate a 120-kilodalton protein (gp120) from extracts of metabolically labeled cells producing HTLV-III. Extracts of infected cells that had been labeled with tritiated leucine or isoleucine were immunoprecipitated with the monoclonal antibody. The immunoprecipitates were fractionated by polyacrylamide gel electrophoresis and the p41 was eluted from the gel bands and subjected to amino-terminal radiolabeled amino acid sequencing by the semiautomated Edman degradation. Leucine residues occurred in cycles 7, 9, 12, 26, 33, and 34 among 40 cycles and isoleucine occurred in cycle 4 among 24 cycles analyzed. Comparison of the data with the deduced amino acid sequence of the env gene product of HTLV-III precisely placed gp41 in the COOH-terminal region of the env gene product. Gp160 is thus the primary env gene product and it is processed into gp120 and gp41.

Apoptosis Induced In Vitro and In Vivo During Infection by Ebola and Marburg Viruses

“…Although lymphocytes were nonpermissive to filoviral infection, interactions with viral glycoproteins and cell surface molecules have not been evaluated. The release of viral glycoproteins in non-virion form resulting from cell lysis, proteolytic cleavage, or shedding of non-membrane associated subunits is reported for other viruses (Little and Huang, 1978;Veronese et al, 1985). Volchkov (1999) recently reported that during EBO infection a nonstructural soluble glycoprotein plus several forms of glycoprotein are secreted from the surface of productively infected cells.…”

Biochemical and immunological characterization of the major structural proteins of feline immunodeficiency virus

“…Antibodies to p40 were occasionally the earliest seen following viral infection and sometimes accompanied antibodies against p130, prior to the appearance of antibodies to core structural peptides (O'Connor et al, 1989). The similarity of these observations to the behaviour of gpl20 and gp41 of HIV Veronese et al, 1985) led us to ascertain whether p130 and p40 were glycoproteins.…”

C-terminal Octylation Rescues an Inactive T20 Mutant

“…Gp120, which is non-covalently attached to the integral membrane subunit gp41, mediates the binding to the target cell receptor CD4 (1) and other co-receptors (2,3). These interactions induce a conformational change in gp41, the first step in a process that will lead to membrane merging (4,5). The N terminus of gp41 contains a stretch of approximately 15 hydrophobic residues named the fusion peptide (6) that are believed to insert into and destabilize the membrane, thus facilitating fusion (7).…”