Abstract: Novel methods and compositions are provided for inhibiting interactions between human immunodeficiency viruses (HIVs) and viral coreceptors, including CXCR4 and/or CCR5 coreceptors. The anti-coreceptor binding agent includes a novel peptide portion of the gp120 envelope protein of HIV-1, as well as peptide analogs and mimetics of this peptide, that specifically binds to, or modulates activity of, the coreceptors(s). The anti-coreceptor binding agent is useful as a prophylactic or therapeutic treatment to prevent or inhibit HIV binding to a susceptible cell and thereby reduces infection and/or moderates or treats related diseases. In alternative embodiments, the peptides, analogs and mimetics are effective to inhibit direct co-receptor binding by HIV virus, coreceptor binding by HIV gp120 proteins or peptides, HIV fusion with target host cells, HIV virion entry into host cells, HIV replication, and HIV transmission between cells and hosts.

Abstract: The present invention provides a purified and isolated nucleic acid molecule encoding serine protease (Met-ase) having Met-ase activity but not Asp-ase activity and a molecular weight of about 30,000 daltons on SDS PAGE under reducing and non-reducing conditions. The present invention also provides a vector comprising this nucleic acid molecule, a prokaryotic or eukaryotic host cell stably transformed or transfected with the vector, as well as a method for detecting this nucleic acid in a sample.