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Title | Structure-based design of a soluble human cytomegalovirus glycoprotein B antigen stabilized in a prefusion-like conformation. |
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Journal, issue, pages | Proc Natl Acad Sci U S A, Vol. 121, Issue 37, Page e2404250121, Year 2024 |
Publish date | Sep 10, 2024 |
Authors | Madeline R Sponholtz / Patrick O Byrne / Alison G Lee / Ajit R Ramamohan / Jory A Goldsmith / Ryan S McCool / Ling Zhou / Nicole V Johnson / Ching-Lin Hsieh / Megan Connors / Krithika P Karthigeyan / Chelsea M Crooks / Adelaide S Fuller / John D Campbell / Sallie R Permar / Jennifer A Maynard / Dong Yu / Matthew J Bottomley / Jason S McLellan / |
PubMed Abstract | Human cytomegalovirus (HCMV) glycoprotein B (gB) is a class III membrane fusion protein required for viral entry. HCMV vaccine candidates containing gB have demonstrated moderate clinical efficacy, ...Human cytomegalovirus (HCMV) glycoprotein B (gB) is a class III membrane fusion protein required for viral entry. HCMV vaccine candidates containing gB have demonstrated moderate clinical efficacy, but no HCMV vaccine has been approved. Here, we used structure-based design to identify and characterize amino acid substitutions that stabilize gB in its metastable prefusion conformation. One variant containing two engineered interprotomer disulfide bonds and two cavity-filling substitutions (gB-C7), displayed increased expression and thermostability. A 2.8 Å resolution cryoelectron microscopy structure shows that gB-C7 adopts a prefusion-like conformation, revealing additional structural elements at the membrane-distal apex. Unlike previous observations for several class I viral fusion proteins, mice immunized with postfusion or prefusion-stabilized forms of soluble gB protein displayed similar neutralizing antibody titers, here specifically against an HCMV laboratory strain on fibroblasts. Collectively, these results identify initial strategies to stabilize class III viral fusion proteins and provide tools to probe gB-directed antibody responses. |
External links | Proc Natl Acad Sci U S A / PubMed:39231203 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.8 - 3.4 Å |
Structure data | EMDB-43667, PDB-8vym: EMDB-43670: Soluble ectodomain of human cytomegalovirus (HCMV) glycoprotein B (gB) stabilized in a prefusion-like conformation in complex with 1G2 and 7H3, global refinement EMDB-43671: Soluble ectodomain of human cytomegalovirus (HCMV) glycoprotein B (gB) stabilized in a prefusion-like conformation in complex with 1G2 and 7H3, local refinement EMDB-43672, PDB-8vyn: |
Chemicals | ChemComp-NAG: |
Source |
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Keywords | VIRAL PROTEIN/IMMUNE SYSTEM / orthoherpesvirus / betaherpesvirus / cytomegalovirus / human betaherpesvirus 5 / human cytomegalovirus / HCMV / glycoprotein B / gB / HCMV gB / VIRAL PROTEIN / 7H3 / 1G2 / VIRAL PROTEIN-IMMUNE SYSTEM complex / prefusion / prefusion-stabilized / disulfide / 7H2 |