2qcy
From Proteopedia
Crystal Structure of a monomeric form of Severe Acute Respiratory Syndrome (SARS) 3C-like protease mutant
Overview
Unlike 3C protease, the SARS-CoV 3C-like protease (3CLpro) is only enzymatically active as a homodimer and its catalysis is under extensive regulation by the unique extra domain. Despite intense studies, two puzzles still remain: 1) how dimer-monomer switch is controlled; and 2) why dimerization is absolutely required for catalysis. Here we report the monomeric crystal structure of the SARS-CoV 3CLpro mutant R298A at a resolution of 1.75 A. Detailed analysis reveals that Arg298 serves as a key component for maintaining dimerization and consequently its mutation will trigger a cooperative switch from dimer to monomer. The monomeric enzyme is irreversibly inactivated because its catalytic machinery is frozen in the collapsed state, characteristic of the formation of a short 310-helix from an active-site loop. Remarkably, dimerization appears to be coupled to catalysis in 3CLpro through use of overlapped residues for two networks, one for dimerization and another for the catalysis.
About this Structure
2QCY is a Single protein structure of sequence from Sars coronavirus. Full crystallographic information is available from OCA.
Reference
Mechanism for Controlling Dimer-monomer Switch and Coupling Dimerization to Catalysis of the SARS-CoV 3C-Like Protease., Shi J, Sivaraman J, Song J, J Virol. 2008 Feb 27;. PMID:18305031 Page seeded by OCA on Sun May 4 14:45:01 2008
