HIV envelope glycoprotein gp120 CD4 binding site (gp120 CD4 binding site)

The HIV envelope glycoprotein gp120 CD4 binding site is a well-characterized region on the surface glycoprotein (gp120) of HIV-1, crucial for initiating viral entry into host cells. gp120 binds to the human CD4 receptor on T lymphocytes, triggering a cascade of conformational changes that allow subsequent binding to a co-receptor (CCR5 or CXCR4) and ultimately fusion of viral and cellular membranes[5][7][9]. The CD4 binding site is a primary target of both therapeutic agents and broadly neutralizing antibodies because blocking this site can prevent viral entry[2][5][8]. However, the region is structurally dynamic and heavily shielded by variable loops and glycans, contributing to immune evasion and making vaccine design particularly challenging[1][5]. Drugs and antibodies targeting this site either sterically block the gp120-CD4 interaction or allosterically stabilize conformations incompatible with further steps in HIV entry[8]. This target is highly relevant for therapies preventing HIV infection or progression, but its high degree of variation and conformational masking present significant obstacles for durable immune or drug targeting[1][5].

Other names

HIV-1 gp120 CD4-binding siteHIV-1 envelope CD4-binding siteHIV Env CD4-binding site

Inhibition of gp120 binding to CD4 receptor (entry inhibition) Antibodies bind and neutralize by blocking CD4 binding or inducing conformational changes incompatible with viral entry[5][8] Allosteric modulation of gp120 to prevent the essential conformational changes required for viral fusion