Vaccinia virus L1R protein (L1R)

The Vaccinia virus L1R protein (L1R or L1) is a 250-residue myristoylated transmembrane envelope protein expressed on the surface of the intracellular mature virion (IMV) form, with a 185-residue disulfide-bonded ectodomain (three intramolecular disulfide bonds linking cysteines 34-57, 49-136, and 116-158) and a C-terminal hydrophobic segment embedded in the viral membrane. Its structure, resolved to 1.51 Å, features a bundle of α-helices packed against a pair of two-stranded β-sheets, including a hydrophobic cavity near the N-terminus that shields the myristate moiety essential for virion assembly. L1R is essential for viral replication, cell entry (enabling virion core penetration into the host cytoplasm via lipid mixing), low-pH-triggered cell-cell fusion, and interacts peripherally with the entry/fusion complex (EFC) components like F9, L5, and A28, as well as indirectly with F9. It serves as a potent target for neutralizing antibodies and is a key component of experimental poxvirus vaccines, with structural conservation across orthopoxviruses like monkeypox virus.

Other names

L1 proteinL1