The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion.
Varicella-zoster virus (VZV) is a medically important alphaherpesvirus that induces fusion of the virion envelope and the cell membrane during entry, and between cells to form polykaryocytes within infected tissues during pathogenesis. All members of the Herpesviridae, including VZV, have a conserve...
Main Authors: | , , , , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Public Library of Science (PLoS)
2021-01-01
|
Series: | PLoS Pathogens |
Online Access: | https://doi.org/10.1371/journal.ppat.1008961 |
id |
doaj-c4890a45b6ac4eeca285c6e266444e51 |
---|---|
record_format |
Article |
spelling |
doaj-c4890a45b6ac4eeca285c6e266444e512021-06-12T04:33:45ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742021-01-01171e100896110.1371/journal.ppat.1008961The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion.Stefan L OliverYi XingDong-Hua ChenSoung Hun RohGrigore D PintilieDavid A BushnellMarvin H SommerEdward YangAndrea CarfiWah ChiuAnn M ArvinVaricella-zoster virus (VZV) is a medically important alphaherpesvirus that induces fusion of the virion envelope and the cell membrane during entry, and between cells to form polykaryocytes within infected tissues during pathogenesis. All members of the Herpesviridae, including VZV, have a conserved core fusion complex composed of glycoproteins, gB, gH and gL. The ectodomain of the primary fusogen, gB, has five domains, DI-V, of which DI contains the fusion loops needed for fusion function. We recently demonstrated that DIV is critical for fusion initiation, which was revealed by a 2.8Å structure of a VZV neutralizing mAb, 93k, bound to gB and mutagenesis of the gB-93k interface. To further assess the mechanism of mAb 93k neutralization, the binding site of a non-neutralizing mAb to gB, SG2, was compared to mAb 93k using single particle cryogenic electron microscopy (cryo-EM). The gB-SG2 interface partially overlapped with that of gB-93k but, unlike mAb 93k, mAb SG2 did not interact with the gB N-terminus, suggesting a potential role for the gB N-terminus in membrane fusion. The gB ectodomain structure in the absence of antibody was defined at near atomic resolution by single particle cryo-EM (3.9Å) of native, full-length gB purified from infected cells and by X-ray crystallography (2.4Å) of the transiently expressed ectodomain. Both structures revealed that the VZV gB N-terminus (aa72-114) was flexible based on the absence of visible structures in the cryo-EM or X-ray crystallography data but the presence of gB N-terminal peptides were confirmed by mass spectrometry. Notably, N-terminal residues 109KSQD112 were predicted to form a small α-helix and alanine substitution of these residues abolished cell-cell fusion in a virus-free assay. Importantly, transferring the 109AAAA112 mutation into the VZV genome significantly impaired viral propagation. These data establish a functional role for the gB N-terminus in membrane fusion broadly relevant to the Herpesviridae.https://doi.org/10.1371/journal.ppat.1008961 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Stefan L Oliver Yi Xing Dong-Hua Chen Soung Hun Roh Grigore D Pintilie David A Bushnell Marvin H Sommer Edward Yang Andrea Carfi Wah Chiu Ann M Arvin |
spellingShingle |
Stefan L Oliver Yi Xing Dong-Hua Chen Soung Hun Roh Grigore D Pintilie David A Bushnell Marvin H Sommer Edward Yang Andrea Carfi Wah Chiu Ann M Arvin The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. PLoS Pathogens |
author_facet |
Stefan L Oliver Yi Xing Dong-Hua Chen Soung Hun Roh Grigore D Pintilie David A Bushnell Marvin H Sommer Edward Yang Andrea Carfi Wah Chiu Ann M Arvin |
author_sort |
Stefan L Oliver |
title |
The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. |
title_short |
The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. |
title_full |
The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. |
title_fullStr |
The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. |
title_full_unstemmed |
The N-terminus of varicella-zoster virus glycoprotein B has a functional role in fusion. |
title_sort |
n-terminus of varicella-zoster virus glycoprotein b has a functional role in fusion. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS Pathogens |
issn |
1553-7366 1553-7374 |
publishDate |
2021-01-01 |
description |
Varicella-zoster virus (VZV) is a medically important alphaherpesvirus that induces fusion of the virion envelope and the cell membrane during entry, and between cells to form polykaryocytes within infected tissues during pathogenesis. All members of the Herpesviridae, including VZV, have a conserved core fusion complex composed of glycoproteins, gB, gH and gL. The ectodomain of the primary fusogen, gB, has five domains, DI-V, of which DI contains the fusion loops needed for fusion function. We recently demonstrated that DIV is critical for fusion initiation, which was revealed by a 2.8Å structure of a VZV neutralizing mAb, 93k, bound to gB and mutagenesis of the gB-93k interface. To further assess the mechanism of mAb 93k neutralization, the binding site of a non-neutralizing mAb to gB, SG2, was compared to mAb 93k using single particle cryogenic electron microscopy (cryo-EM). The gB-SG2 interface partially overlapped with that of gB-93k but, unlike mAb 93k, mAb SG2 did not interact with the gB N-terminus, suggesting a potential role for the gB N-terminus in membrane fusion. The gB ectodomain structure in the absence of antibody was defined at near atomic resolution by single particle cryo-EM (3.9Å) of native, full-length gB purified from infected cells and by X-ray crystallography (2.4Å) of the transiently expressed ectodomain. Both structures revealed that the VZV gB N-terminus (aa72-114) was flexible based on the absence of visible structures in the cryo-EM or X-ray crystallography data but the presence of gB N-terminal peptides were confirmed by mass spectrometry. Notably, N-terminal residues 109KSQD112 were predicted to form a small α-helix and alanine substitution of these residues abolished cell-cell fusion in a virus-free assay. Importantly, transferring the 109AAAA112 mutation into the VZV genome significantly impaired viral propagation. These data establish a functional role for the gB N-terminus in membrane fusion broadly relevant to the Herpesviridae. |
url |
https://doi.org/10.1371/journal.ppat.1008961 |
work_keys_str_mv |
AT stefanloliver thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT yixing thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT donghuachen thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT sounghunroh thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT grigoredpintilie thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT davidabushnell thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT marvinhsommer thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT edwardyang thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT andreacarfi thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT wahchiu thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT annmarvin thenterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT stefanloliver nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT yixing nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT donghuachen nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT sounghunroh nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT grigoredpintilie nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT davidabushnell nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT marvinhsommer nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT edwardyang nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT andreacarfi nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT wahchiu nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion AT annmarvin nterminusofvaricellazostervirusglycoproteinbhasafunctionalroleinfusion |
_version_ |
1721381084342517760 |