Functional dissection of the alphavirus capsid protease: Sequence requirements for activity
Autor(es): Thomas Saijo, Rai Jagdish, John Lijo, Günther Stephan, Drosten Christian, Pützer Brigitte M, Schaefer Stephan
Resumo: The alphavirus capsid is multifunctional - plays a key role in the viral life cycle. The nucleocapsid domain is released by the self-cleavage activity of the serine protease domain within the capsid. All alphaviruses analyzed to date show this autocatalytic cleavage. Here we have analyzed the sequence requirements for the cleavage activity of Chikungunya virus capsid protease of genus alphavirus. Amongst alphaviruses, the C-terminal amino acid tryptophan (W261) is conserved - found to be important for the cleavage. Mutating tryptophan to alanine (W261A) completely inactivated the protease. Other amino acids near W261 were not having any effect on the activity of this protease. However, serine protease inhibitor AEBSF did not inhibit the activity. Through error-prone PCR we found that isoleucine 227 is important for the effective activity. The loss of activity was analyzed further by molecular modelling - comparison of WT - mutant structures. It was found that lysine introduced at position 227 is spatially very close to the catalytic triad - may disrupt electrostatic interactions in the catalytic site - thus inactivate the enzyme. We are also examining other sequence requirements for this protease activity. We analyzed various amino acid sequence requirements for the activity of ChikV capsid protease - found that amino acids outside the catalytic triads are important for the activity.
Imprenta: Virology Journal, v. 7, p. 327, 2010
Identificador do objeto digital: 10.1186/1743-422X-7-327
Descritores: Chikungunya virus - Biosynthesis ; Chikungunya virus - DNA ; Chikungunya virus - Molecular structure ; Chikungunya virus - Pathogenesis ; Chikungunya virus - Proteins ; Chikungunya Virus - Virus
Data de publicação: 2010
