Gp41

gp41

Diagram of HIV membrane fusion mediated by gp41.

gp41 is a glycoprotein that plays a crucial role in the HIV infection process. It is a component of the HIV envelope protein, which is essential for the virus's ability to infect host cells. gp41 is involved in the fusion of the viral membrane with the host cell membrane, a critical step in the viral entry process.

Structure

Illustration showing the structural changes in gp41 during membrane fusion.

gp41 is a transmembrane protein that is part of the HIV envelope glycoprotein complex, which also includes gp120. The gp41 protein is anchored in the viral membrane and extends outward, where it interacts with gp120. Upon binding of gp120 to the CD4 receptor and a coreceptor on the host cell, gp41 undergoes a conformational change that facilitates membrane fusion.

Function

gp41's primary function is to mediate the fusion of the HIV viral envelope with the host cell membrane. This process is initiated when gp120 binds to the CD4 receptor on the surface of a T helper cell, followed by binding to a coreceptor such as CCR5 or CXCR4. This binding triggers gp41 to undergo a series of structural changes, forming a six-helix bundle that brings the viral and cellular membranes into close proximity, allowing them to fuse.

Role in HIV Infection

The fusion of the viral and host cell membranes is a critical step in the HIV life cycle. Once fusion occurs, the viral capsid is released into the host cell's cytoplasm, where it can begin the process of reverse transcription and integration into the host genome. gp41 is therefore a key target for antiretroviral drugs designed to inhibit HIV entry.

Therapeutic Target

Due to its essential role in HIV entry, gp41 is a target for several classes of antiretroviral drugs, including fusion inhibitors. These drugs aim to block the conformational changes in gp41 that are necessary for membrane fusion, thereby preventing the virus from entering host cells. One example of a fusion inhibitor is enfuvirtide, which binds to gp41 and inhibits its function.

Related pages

• HIV
• gp120
• HIV life cycle
• Antiretroviral drug
• Fusion inhibitor