1.National Laboratory
of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences,
Beijing 100101, China; 2.Structural Biology Laboratory,
Tsinghua University, Beijing 100084, China; 3.Tianjin Key Laboratory
of Protein Science, College of Life Sciences, Nankai University, Tianjin
300071, China; 4.National Laboratory
of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences,
Beijing 100101, China；Structural Biology Laboratory,
Tsinghua University, Beijing 100084, China；Tianjin Key Laboratory
of Protein Science, College of Life Sciences, Nankai University, Tianjin
300071, China;
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History+
Published Online
2010-02-01
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(392KB)
Abstract
During severe acute respiratory syndrome coronavirus (SARS-CoV) infection, the activity of the replication/transcription complexes (RTC) quickly peaks at 6 hours post infection (h.p.i) and then diminishes significantly in the late post-infection stages. This “down-up-down” regulation of RNA synthesis distinguishes different viral stages: primary translation, genome replication, and finally viron assembly. Regarding the nsp8 as the primase in RNA synthesis, we confirmed that the proteolysis product of the primase (nsp8) contains the globular domain (nsp8C), and indentified the resectioning site that is notably conserved in all the three groups of coronavirus. We subsequently crystallized the complex of SARS-CoV nsp8C and nsp7, and the 3-D structure of this domain revealed its capability to interfuse into the hexadecamer super-complex. This specific proteolysis may indicate one possible mechanism by which coronaviruses to switch from viral infection to genome replication and viral assembly stages.
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(392KB)
