-
Envelope glycoprotein GP120
Envelope glycoprotein GP120 (or gp120) is a glycoprotein exposed on the surface of the HIV envelope. The 120 in its name comes from itsmolecular weight of 120 kilodaltons. Gp120 is essential for virus entry into cells as it plays a vital role in attachment to specific cell surface receptors. These receptors are DC-SIGN,[1] Heparan Sulfate Proteoglycan[2] and a specific interaction with the CD4 receptor,[3] particularly on helper T-cells. Binding to CD4 induces the start of a cascade of conformational changes in gp120 and gp41 that lead to the fusion of the viral with the host cell membrane. Binding to CD4 is mainly electrostatic although there are van der Waals interactions and hydrogen bonds[citation needed].
Gp120 is coded by the HIV env gene, which is around 2.5 kb long and codes for around 850 amino acids.[4] The primary env product is the protein gp160, which gets cleaved to gp120 and gp41 in the endoplasmatic reticulum by the cellular protease furin.[5] The crystal structure of core gp120 shows an organization with an outer domain, an inner domain with respect to its termini and a bridging sheet. Gp120 is anchored to the viral membrane, or envelope, via non-covalent bonds with the transmembrane glycoprotein, gp41. Three gp120s and gp41s combine in a trimer ofheterodimers to form the envelope spike,[6] which mediates attachment to and entry into the host cell.
Car Diagnostic Tools ECU Chip Tuning Airbag Reset Tool OBD2 Code Scanner Auto Locksmith Tool
FAQ > Envelope glycoprotein GP120