The potential molecular targets of marine sulfated polymannuroguluronate interfering with HIV-1 entry: Interaction between SPMG and HIV-1 rgp120 and CD4 molecule

• Published in: Antiviral research 2003-07, Vol.59 (2), p.127-135
• Main Authors: Meiyu, Geng, Fuchuan, Li, Xianliang, Xin, Jing, Li, Zuowei, Yan, Huashi, Guan
• Format: Article
• Language: English
• Subjects: Anti-HIV Agents - chemistry; Anti-HIV Agents - isolation & purification; Anti-HIV Agents - metabolism; Anti-HIV Agents - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiviral agents; Binding Sites; Biological and medical sciences; CD4 Antigens - chemistry; CD4 Antigens - drug effects; CD4 Antigens - metabolism; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - metabolism; CD4-Positive T-Lymphocytes - virology; Flow cytometry; General pharmacology; HIV Envelope Protein gp120 - chemistry; HIV Envelope Protein gp120 - drug effects; HIV Envelope Protein gp120 - metabolism; HIV-1 - drug effects; HIV-1 - physiology; Humans; In Vitro Techniques; Macromolecular Substances; Medical sciences; Models, Molecular; Peptide Fragments - chemistry; Peptide Fragments - drug effects; Peptide Fragments - metabolism; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Polysaccharides - chemistry; Polysaccharides - isolation & purification; Polysaccharides - metabolism; Polysaccharides - pharmacology; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; rgp120; sCD4; Sulfated polymannuroguluronate; Surface Plasmon Resonance; V3 loop
• ISSN: 0166-3542; 1872-9096
• DOI: 10.1016/S0166-3542(03)00068-8

The potential targets of marine sulfated polymannuroguluronate (SPMG) involved in inhibition of HIV-1 entry were investigated by surface plasmon resonance and flow cytometry. Results indicated that binding of SPMG either to soluble oligomeric rgp120 or to complexed rgp120–sCD4 mainly resided in V3 loop region. In addition, SPMG was shown to be less accessible for sCD4 when sCD4 had pre-interacted with rgp120, though SPMG per se multivalently bound to sCD4 with relatively low affinity. While the pre-incubation of SPMG with rgp120 caused a partial blockade of rgp120 binding to sCD4, suggesting that SPMG either shared common binding sites on gp120 with sCD4 or masked the docking sites of gp120 for sCD4. Taken together, V3 domain was demonstrated to be the major site mediating interaction of SPMG with complexed rgp120–sCD4. It seems likely that SPMG binds to both rgp120 and sCD4, but has less accessibility for sCD4 when sCD4 has already bound to rgp120. Nevertheless, addition of SPMG either prior to or after the interaction of rgp120 with sCD4 may suppress rgp120 binding to sCD4. The exact pattern of this trimolecular complex formation at the cell membrane-anchored virus level requires further clarification.