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Inhibition of the Protease Activity of Influenza Virus RNA Polymerase PA Subunit by Viral Matrix Protein
Author(s) -
Hara Koyu,
Shiota Mayumi,
Kido Hiroshi,
Watanabe Ken,
Nagata Kyosuke,
Toyoda Tetsuya
Publication year - 2003
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2003.tb03413.x
Subject(s) - protease , serine protease , biology , microbiology and biotechnology , polymerase , trypsin , protein subunit , virus , chymotrypsin , rna polymerase , viral matrix protein , biochemistry , enzyme , rna dependent rna polymerase , rna , virology , gene
Influenza virus PA is a subunit of RNA‐dependent RNA polymerase. We demonstrated that PA has a unique chymotrypsin‐like serine protease activity with Ser624 as an active site. To obtain further insight into the role of the protease activity of PA in viral proliferation, we examined the interaction between PA and matrix protein (M1). Both M1 purified from virion and hexa‐histidine‐tagged M1 expressed in Escherichia coli bound to PA. Hexa‐histidine‐tagged M1 pulled down PA. The interaction of PA with M1 was sensitive to ionic strength, suggesting that the interaction is formed by electrostatic force. Using Suc‐Leu‐Leu‐Val‐Tyr‐MCA, a specific substrate for PA protease, M1 was demonstrated to inhibit the amidolytic activity of PA, whereas M1 did not inhibit that of chymotrypsin or trypsin at all. These results suggest that M1 binds to and inhibits the amidolytic activity of PA.