CD4 Binding Site on HIV Envelope Glycoprotein (CD4bs)

The CD4 binding site (CD4bs) is a highly conserved, conformational region on the envelope glycoprotein gp120 of HIV-1, HIV-2, and SIV. This site is essential for viral entry into host cells. The primary function of the CD4bs is to mediate the initial attachment of the virus to its main cellular receptor, CD4, which is found on T-helper lymphocytes and other immune cells. Binding to the host cell’s CD4 receptor triggers structural rearrangements in gp120 that allow subsequent binding to a chemokine coreceptor (CCR5 or CXCR4), ultimately leading to membrane fusion via changes in gp41. The CD4bs is a major site of vulnerability on Env, and broadly neutralizing antibodies targeting this region can block infection.

Other names

HIV gp120 CD4 Binding Sitegp120 CD4bsCD4bs on gp120

Inhibition of viral entry by blocking CD4 binding or subsequent conformational changes required for co-receptor binding and membrane fusion.