The envelope glycoprotein of HIV-1 may have incorporated the CD4 binding site from HLA-DQ beta 1.
An hypothesis is presented which states that the increased binding for CD4 by the envelope glycoprotein (gp120) from HIV-1 compared with that from HIV-2 is due to the env gene from HIV-1 having at some stage incorporated exon 2 of the gene coding for the beta subunit of a class II MHC protein, possibly HLA-DQ, which contains part of the CD4 binding site. Evidence is presented from amino acid sequence analysis and consideration of putative binding residues from gp120 and HLA-DQ.
Brinkworth
R I
RI
Graduate School of Science and Technology, Bond University, Gold Coast, Queensland, Australia.
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D015704:CD4 Antigens / Q000378:metabolism*; D004279:DNA, Viral / Q000235:genetics; D005091:Exons; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006683:HLA-DQ Antigens / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
D015704:CD4 Antigens; D004279:DNA, Viral; D015699:HIV Envelope Protein gp120; D006683:HLA-DQ Antigens