title: The role of calcium and N-linked glycans in the oligomerization and carbohydrate binding properties of human immunodeficiency virus external envelope glycoprotein.
abstract: Envelope glycoproteins of human immunodeficiency virus (gp120 and gp41) occur as oligomers. Here, we show by gel filtration analysis that gp120 oligomerization in vitro is calcium- and temperature-dependent. Recombinant gp120 (rgp120) species were recovered as monomers at 20 degrees C in the absence of calcium, but as tetramers at 37 degrees C in 10 mM CaCl2. Under the latter condition, N-glycanase-deglycosylated rgp120 formed hexamers. Relative to intact rgp120, which has been reported to display carbohydrate-binding properties for N-acetyl-beta-D-glucosaminyl and mannosyl residues, deglycosylation enhanced rgp120 specific binding to mannose-divinylsulfone-agarose, para-aminophenyl-beta-D-GlcNAc-agarose and fetuin-agarose matrices. Taken together, these results rule out the role of homologous lectin-carbohydrate interactions via N-linked glycans in the rgp120 oligomerization, even though its lectin properties may also be calcium-dependent. Deglycosylation may unmask domains of rgp120 polypeptide backbone that independently play a role either in rgp120 lectin activity or in calcium-dependent oligomerization.
authors: Laboratoire de Biologie Cellulaire, Faculté de Médecine Paris-Nord, Bobigny, France.
authors: M
authors: M
authors: Haidar
authors: N
authors: N
authors: Seddiki
authors: J C
authors: JC
authors: Gluckman
authors: L
authors: L
authors: Gattegno
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002850:Chromatography, Gel; D006678:HIV / Q000378:metabolism*; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000378:metabolism; D015700:HIV Envelope Protein gp41 / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D037102:Lectins; D046911:Macromolecular Substances; D011134:Polysaccharides / Q000378:metabolism* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D037102:Lectins; D046911:Macromolecular Substances; D011134:Polysaccharides; D011994:Recombinant Proteins; D002118:Calcium