Crystal structure of SARS-CoV-2 Orf9b in complex with human TOM70 suggests unusual virus-host interactions

Gao，Xiaopan1,2; Zhu，Kaixiang1; Qin，Bo1,2; Olieric，Vincent3; Wang，Meitian3; Cui，Sheng1,2

2021-12-01

10.1038/s41467-021-23118-8

Nature Communications   影响因子和分区

2041-1723

2041-1723

Although the accessory proteins are considered non-essential for coronavirus replication, accumulating evidences demonstrate they are critical to virus-host interaction and pathogenesis. Orf9b is a unique accessory protein of SARS-CoV-2 and SARS-CoV. It is implicated in immune evasion by targeting mitochondria, where it associates with the versatile adapter TOM70. Here, we determined the crystal structure of SARS-CoV-2 orf9b in complex with the cytosolic segment of human TOM70 to 2.2 Å. A central portion of orf9b occupies the deep pocket in the TOM70 C-terminal domain (CTD) and adopts a helical conformation strikingly different from the β-sheet-rich structure of the orf9b homodimer. Interactions between orf9b and TOM70 CTD are primarily hydrophobic and distinct from the electrostatic interaction between the heat shock protein 90 (Hsp90) EEVD motif and the TOM70 N-terminal domain (NTD). Using isothermal titration calorimetry (ITC), we demonstrated that the orf9b dimer does not bind TOM70, but a synthetic peptide harboring a segment of orf9b (denoted C-peptide) binds TOM70 with nanomolar K. While the interaction between C-peptide and TOM70 CTD is an endothermic process, the interaction between Hsp90 EEVD and TOM70 NTD is exothermic, which underscores the distinct binding mechanisms at NTD and CTD pockets. Strikingly, the binding affinity of Hsp90 EEVD motif to TOM70 NTD is reduced by ~29-fold when orf9b occupies the pocket of TOM70 CTD, supporting the hypothesis that orf9b allosterically inhibits the Hsp90/TOM70 interaction. Our findings shed light on the mechanism underlying SARS-CoV-2 orf9b mediated suppression of interferon responses.

SCI

英语

NI论文

通讯

National Key Research and Development Program of China["2016YFD0500300","2019YFC0840602"] ; National Natural Science Foundation of China[81971985,82072291,81772207,11775308] ; Chinese Academy of Medical Science (CAMS) Innovation Fund for Medical Sciences["2017-I2M-1-014","2016-I2M-1-013"] ; Guangdong Foundation for Basic and Applied Basic Research[2019B1515120041]

Science & Technology - Other Topics

Multidisciplinary Sciences

WOS:000658733500011

NATURE RESEARCH

2-s2.0-85105855839

Scopus

1.NHC Key Laboratory of Systems Biology of Pathogens,Institute of Pathogen Biology,Chinese Academy of Medical Sciences and Peking Union Medical College,Beijing,China
2.Sanming Project of Medicine in Shenzhen,National Clinical Research Center for Infectious Diseases,Shenzhen Third People’s Hospital,Southern University of Science and Technology,Shenzhen,China
3.Swiss Light Source Paul Scherrer Institut,Villigen,Switzerland

Gao，Xiaopan,Zhu，Kaixiang,Qin，Bo,et al. Crystal structure of SARS-CoV-2 Orf9b in complex with human TOM70 suggests unusual virus-host interactions[J]. Nature Communications,2021,12(1).

Gao，Xiaopan,Zhu，Kaixiang,Qin，Bo,Olieric，Vincent,Wang，Meitian,&Cui，Sheng.(2021).Crystal structure of SARS-CoV-2 Orf9b in complex with human TOM70 suggests unusual virus-host interactions.Nature Communications,12(1).

Gao，Xiaopan,et al."Crystal structure of SARS-CoV-2 Orf9b in complex with human TOM70 suggests unusual virus-host interactions".Nature Communications 12.1(2021).