title: Conserved structural features in the interaction between retroviral surface and transmembrane glycoproteins?
abstract: Among the retroviruses, the surface (SU) and transmembrane (TM) glycoproteins of lentiviruses are linked exclusively by noncovalent bonds. For some C-type retroviruses, however, a small proportion of the SU proteins has been shown to be linked to their TM proteins by a disulfide bond, with the remainder being noncovalently associated. A region near the carboxyl terminus of the HIV-1 SU glycoprotein has been implicated in contacting the TM glycoprotein. Computer modelling indicates that this region of divergent lentivirus and oncovirus SU glycoproteins forms a structurally conserved "pocket" which could accommodate a "knob"-like protrusion formed by an immunodominant region in the TM protein containing the CxxxxxC (lentiviruses) or CxxxxxxCC (C- and D-type viruses) motif. An anti-idiotypic monoclonal antibody, raised against a monoclonal antibody reacting with a sequence in the "pocket" of HIV-1 gp120, was found to bind to synthetic peptides close to the CxxxxxC motif. It is suggested that part of the SU-TM linkage mechanism for the lentiviruses and oncoviruses is a 'knob and socket' structure and that the interaction between SU and TM proteins is similar in one region for lentiviruses and C-type as well as D-type viruses. The conserved knob and socket linkage may be relevant to a mechanism for viral-cell membrane fusion that is broadly common to all of these retroviruses.
authors.affiliation: Chester Beatty Laboratories, Institute of Cancer Research, London, England.
authors.forename: T F
authors.initials: TF
authors.lastname: Schulz
authors.forename: B A
authors.initials: BA
authors.lastname: Jameson
authors.forename: L
authors.initials: L
authors.lastname: Lopalco
authors.forename: A G
authors.initials: AG
authors.lastname: Siccardi
authors.forename: R A
authors.initials: RA
authors.lastname: Weiss
authors.forename: J P
authors.initials: JP
authors.lastname: Moore
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics; D015700:HIV Envelope Protein gp41 / Q000737:chemistry / Q000235:genetics; D015497:HIV-1 / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D011485:Protein Binding; D012190:Retroviridae / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D006023:Glycoproteins; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D014759:Viral Envelope Proteins