Sugiyama Kanako, Obayashi Eiji, Kawaguchi Atsushi, Suzuki Yukari, Tame Jeremy R H, Nagata Kyosuke, Park Sam-Yong
Protein Design Laboratory, Yokohama City University, Tsurumi, Yokohama, Japan.
EMBO J. 2009 Jun 17;28(12):1803-11. doi: 10.1038/emboj.2009.138. Epub 2009 May 21.
Influenza virus RNA-dependent RNA polymerase is a multi-functional heterotrimer, which uses a 'cap-snatching' mechanism to produce viral mRNA. Host cell mRNA is cleaved to yield a cap-bearing oligonucleotide, which can be extended using viral genomic RNA as a template. The cap-binding and endonuclease activities are only activated once viral genomic RNA is bound. This requires signalling from the RNA-binding PB1 subunit to the cap-binding PB2 subunit, and the interface between these two subunits is essential for the polymerase activity. We have defined this interaction surface by protein crystallography and tested the effects of mutating contact residues on the function of the holo-enzyme. This novel interface is surprisingly small, yet, it has a crucial function in regulating the 250 kDa polymerase complex and is completely conserved among avian and human influenza viruses.
流感病毒RNA依赖的RNA聚合酶是一种多功能异源三聚体，它利用“抢帽”机制产生病毒mRNA。宿主细胞mRNA被切割以产生携带帽的寡核苷酸，该寡核苷酸可以使用病毒基因组RNA作为模板进行延伸。帽结合和内切核酸酶活性只有在病毒基因组RNA结合后才被激活。这需要从RNA结合的PB1亚基向帽结合的PB2亚基发出信号，并且这两个亚基之间的界面对于聚合酶活性至关重要。我们通过蛋白质晶体学定义了这种相互作用表面，并测试了突变接触残基对全酶功能的影响。这个新的界面出奇的小，然而，它在调节250 kDa聚合酶复合物方面具有关键功能，并且在禽流感病毒和人流感病毒中完全保守。
