دورية أكاديمية
Different functional states of fusion protein gB revealed on human cytomegalovirus by cryo electron tomography with Volta phase plate.
| العنوان: | Different functional states of fusion protein gB revealed on human cytomegalovirus by cryo electron tomography with Volta phase plate. |
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| المؤلفون: | Zhu Si, Jiayan Zhang, Sakar Shivakoti, Ivo Atanasov, Chang-Lu Tao, Wong H Hui, Kang Zhou, Xuekui Yu, Weike Li, Ming Luo, Guo-Qiang Bi, Z Hong Zhou |
| المصدر: | PLoS Pathogens, Vol 14, Iss 12, p e1007452 (2018) |
| بيانات النشر: | Public Library of Science (PLoS), 2018. |
| سنة النشر: | 2018 |
| المجموعة: | LCC:Immunologic diseases. Allergy LCC:Biology (General) |
| مصطلحات موضوعية: | Immunologic diseases. Allergy, RC581-607, Biology (General), QH301-705.5 |
| الوصف: | Human cytomegalovirus (HCMV) enters host by glycoprotein B (gB)-mediated membrane fusion upon receptor-binding to gH/gL-related complexes, causing devastating diseases such as birth defects. Although an X-ray crystal structure of the recombinant gB ectodomain at postfusion conformation is available, the structures of prefusion gB and its complex with gH/gL on the viral envelope remain elusive. Here, we demonstrate the utility of cryo electron tomography (cryoET) with energy filtering and the cutting-edge technologies of Volta phase plate (VPP) and direct electron-counting detection to capture metastable prefusion viral fusion proteins and report the structures of glycoproteins in the native environment of HCMV virions. We established the validity of our approach by obtaining cryoET in situ structures of the vesicular stomatitis virus (VSV) glycoprotein G trimer (171 kD) in prefusion and postfusion conformations, which agree with the known crystal structures of purified G trimers in both conformations. The excellent contrast afforded by these technologies has enabled us to identify gB trimers (303kD) in two distinct conformations in HCMV tomograms and obtain their in situ structures at up to 21 Å resolution through subtomographic averaging. The predominant conformation (79%), which we designate as gB prefusion conformation, fashions a globular endodomain and a Christmas tree-shaped ectodomain, while the minority conformation (21%) has a columnar tree-shaped ectodomain that matches the crystal structure of the "postfusion" gB ectodomain. We also observed prefusion gB in complex with an "L"-shaped density attributed to the gH/gL complex. Integration of these structures of HCMV glycoproteins in multiple functional states and oligomeric forms with existing biochemical data and domain organization of other class III viral fusion proteins suggests that gH/gL receptor-binding triggers conformational changes of gB endodomain, which in turn triggers two essential steps to actuate virus-cell membrane fusion: exposure of gB fusion loops and unfurling of gB ectodomain. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1553-7366 1553-7374 |
| Relation: | https://doaj.org/toc/1553-7366; https://doaj.org/toc/1553-7374 |
| DOI: | 10.1371/journal.ppat.1007452 |
| URL الوصول: | https://doaj.org/article/753988f7f4f94e23817c7adc12b950c8 |
| رقم الأكسشن: | edsdoj.753988f7f4f94e23817c7adc12b950c8 |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 15537366 15537374 |
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| DOI: | 10.1371/journal.ppat.1007452 |