Gp120

Gp120 is a glycoprotein exposed on the surface of the HIV envelope. The 120 in its name comes from its molecular weight of 120 kilodaltons. Gp120 is essential for virus entry into cells as it plays a vital role in seeking out specific cell surface receptors for entry.

Structure

Gp120 is a glycoprotein composed of two subunits that are non-covalently bound. The outer domain is immunodominant and contains binding sites for neutralizing antibodies. The inner domain is immunorecessive and helps stabilize the outer domain. The bridging sheet, a 4-stranded anti-parallel beta sheet, connects the inner and outer domains and is involved in CD4 binding.

Function

Gp120 is necessary for HIV to enter human cells. It does this by binding to the CD4 receptor on the cell surface, which triggers a structural change in gp120 allowing it to bind a second receptor called a co-receptor. The co-receptor is typically CCR5 or CXCR4, but others can be used in certain circumstances. Once gp120 has bound to both the CD4 receptor and the co-receptor, the virus can enter the cell.

Role in disease

Gp120 plays a crucial role in the ability of HIV to infect human cells, and thus plays a key role in the pathogenesis of HIV and AIDS. It is also the target of many antiretroviral drugs, which aim to prevent the virus from entering cells.

Research

Research into gp120 is ongoing, with a focus on understanding its structure and function, and developing drugs and vaccines that can target it. Some of this research has led to the development of drugs that can block the binding of gp120 to CD4 or the co-receptor, preventing the virus from entering cells.

See also

• HIV
• AIDS
• Antiretroviral drugs
• CD4
• CCR5
• CXCR4

Gp120 Resources
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