The Molecular Mechanisms Of ZCS For Preventing Sexual Transmission Of HIV-1

ZCS is a kind of polyanionic polysaccharide with modified sulfate group and a average molecular weight of 24KDa.Our previous woks have demonstrated a signification inhibition of ZCS on the replication of HIV-1 in vitro. In order to elucidate the anti-HIV-1 mechanisms, the interaction of ZCS with several potential targets was investigated by surface plasmon resonance analysis and ELISA. The main results were got as follows:(1) ZCS can inhibit the binding of gp120 and CD4. ZCS can significantly inhibit the binding of two tropism gp120 and CD4. Inhibition rates were 82.3%(gp120ⅢB) and 94.3% (gpl20ADA)(2) ZCS can quench the fluorescence of BSA and was a single static quenching process. BSA was strongly bound to ZCS with the molar ratio of 1.27:1. The binding distance ZCS and BSA was 4.34nm. The hydrophobic force was the main binding force.(3) ZCS strongly bound to gp120. The affinity constant of gp120ⅢB-ZCS interaction and The affinity constant of gp120ADA-ZCS interaction were separately 136nM and 442nM by kinetic analysis through BIAevaluation 4.1 software.The affinity of ZCS bound with gp120ⅢB was higher than that of ZCS bound with gp120ADA.(4) ZCS strongly bound to V3 loop. The affinity constant of V3ⅢB-ZCS interaction and The affinity constant of V3 ADA-ZCS interaction were separately 33.1nM and 20.0nM by kinetic analysis through BIAevaluation 4.1 software. The affinity constant of V3 GF-6 (Conservative sequence of V3, GPGRAF)-ZCS interaction was 95.3nM by kinetic analysis through BIAevaluation 4.1 software. The affinity of ZCS bound with V3 ADAwas higher than that of ZCS bound with V3ⅢB.(5) ZCS bound to CD4 with low affinity. The affinity constant of CD4-ZCS interaction was1940nM by kinetic analysis through BIAevaluation 4.1 software.(6) ZCS can inhibit activity of HIV-1 reverse transcriptase. Fifty percent inhibitory concentration(IC50) value of ZCS against HIV-1 reverse transcriptase was 7.437±1.042μg/ml.