Maurer UE, Zeev-Ben-Mordehai T, Pandurangan AP, Cairns TM, Hannah BP, Whitbeck JC, Eisenberg RJ, Cohen GH, Topf M, Huiskonen JT, Grünewald K. The structure of herpesvirus fusion glycoprotein B-bilayer complex reveals the protein-membrane and lateral protein-protein interaction.
Structure 2013;
21:1396-405. [PMID:
23850455 PMCID:
PMC3737472 DOI:
10.1016/j.str.2013.05.018]
[Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 12/19/2022]
Abstract
Glycoprotein B (gB) is a key component of the complex herpesvirus fusion machinery. We studied membrane interaction of two gB ectodomain forms and present an electron cryotomography structure of the gB-bilayer complex. The two forms differed in presence or absence of the membrane proximal region (MPR) but showed an overall similar trimeric shape. The presence of the MPR impeded interaction with liposomes. In contrast, the MPR-lacking form interacted efficiently with liposomes. Lateral interaction resulted in coat formation on the membranes. The structure revealed that interaction of gB with membranes was mediated by the fusion loops and limited to the outer membrane leaflet. The observed intrinsic propensity of gB to cluster on membranes indicates an additional role of gB in driving the fusion process forward beyond the transient fusion pore opening and subsequently leading to fusion pore expansion.
Full-length gB ectodomain has a structure similar to the ectodomain lacking the MPR
The gB-bilayer structure reveals that the interaction is limited to the outer leaflet
gB trimers have an intrinsic propensity to interact laterally and form protein arrays
Arrays of gB trimers on membranes render the fusion pore open state irreversible
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