NBD-557 is a potentially HIV-1 inhibitor.IC50 Value: Target: HIVNBD-557, is small molecule organic compounds with drug-like properties. It showed potent cell fusion and virus-cell fusion inhibitory activity at low micromolar levels. A systematic study showed that NBD-557 target viral entry by inhibiting the binding of HIV-1 envelope glycoprotein gp120 to the cellular receptor CD4 but did not inhibit reverse transcriptase, integrase, or protease, indicating that they do not target the later stages of the HIV-1 life cycle to inhibit HIV-1 infection. NBD-557 potent inhibitors of both X4 and R5 viruses tested in CXCR4 and CCR5 expressing cell lines, respectively, indicating that its anti-HIV-1 activity is not dependent on the coreceptor tropism of the virus. A surface plasmon resonance study, which measures binding affinity, clearly demonstrated that NBD-557 bind to unliganded HIV-1 gp120 but not to the cellular receptor CD4. NBD-557 was active against HIV-1 laboratory-adapted strains including an AZT-resistant strain and HIV-1 primary isolates, indicating that NBD-557 can potentially be further modified to become potent HIV-1 entry inhibitors.

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