Gp41
Encyclopedia
gp41 is a subunit of the envelope protein complex
of retroviruses, including Human immunodeficiency virus
(HIV) and Simian-Human immunodeficiency virus
. This glycoprotein
subunit remains non-covalently
-bound to gp120
, and provides the second step by which HIV enters
the cell. It is originally buried within the viral
envelope, but, when gp120 binds to a CD4
, gp120 changes its conformation
, causing gp41 to become exposed, where it can assist in fusion with the host cell.
Fusion inhibitor drugs such as enfuvirtide
block the fusion process by binding to gp41.
The Env gene does not, in fact, code for gp120 and gp41, but for a precursor to both, gp160. During HIV
reproduction, the host cell's own enzymes cleave gp160 into gp120 and gp41. See Replication cycle of HIV.
A polyclonal caprine antibody is in phase II human clinical trial
s that targets, among others sites, the GP41 transmembrane glycoprotein. This is a new class of treatment for HIV infection. The trials are being conducted for a patented biologic developed by Virionyx, a New Zealand Company.
Protein complex
A multiprotein complex is a group of two or more associated polypeptide chains. If the different polypeptide chains contain different protein domain, the resulting multiprotein complex can have multiple catalytic functions...
of retroviruses, including Human immunodeficiency virus
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
(HIV) and Simian-Human immunodeficiency virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
. This glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
subunit remains non-covalently
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
-bound to gp120
Gp120
Envelope glycoprotein 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...
, and provides the second step by which HIV enters
Viral entry
Viral entry is the earliest stage of infection in the viral life cycle, as the virus comes into contact with the host cell and introduces viral material into the cell. The major steps involved in viral entry are shown below. Despite the variation among viruses, the generalities are quite similar...
the cell. It is originally buried within the viral
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
envelope, but, when gp120 binds to a CD4
CD4
CD4 is a glycoprotein expressed on the surface of T helper cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 before being named CD4 in 1984...
, gp120 changes its conformation
Conformational isomerism
In chemistry, conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted exclusively by rotations about formally single bonds...
, causing gp41 to become exposed, where it can assist in fusion with the host cell.
Fusion inhibitor drugs such as enfuvirtide
Enfuvirtide
Enfuvirtide is an HIV fusion inhibitor, the first of a novel class of antiretroviral drugs used in combination therapy for the treatment of HIV-1 infection. It is marketed under the trade name Fuzeon ....
block the fusion process by binding to gp41.
The Env gene does not, in fact, code for gp120 and gp41, but for a precursor to both, gp160. During HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
reproduction, the host cell's own enzymes cleave gp160 into gp120 and gp41. See Replication cycle of HIV.
A polyclonal caprine antibody is in phase II human clinical trial
Clinical trial
Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...
s that targets, among others sites, the GP41 transmembrane glycoprotein. This is a new class of treatment for HIV infection. The trials are being conducted for a patented biologic developed by Virionyx, a New Zealand Company.
See also
- HIV structure and genomeHIV structure and genomeThe genome and proteins of HIV have been the subject of extensive research since the discovery of the virus in 1983. The discovery of the virus itself was not until two years after the first major cases of AIDS associated illnesses were reported in 1981.-Structure:...
- Discovery and development of CCR5 receptor antagonistsDiscovery and development of CCR5 receptor antagonistsCCR5 receptor antagonists are a class of small molecules that antagonize the CCR5 receptor. The C-C motif chemokine receptor CCR5 is involved in the HIV entry process...