8月5日,，由美國(guó)和日本等國(guó)科學(xué)家組成的研究小組報(bào)告說(shuō),，他們發(fā)現(xiàn)甲型H1N1流感病毒能適應(yīng)人體并高效復(fù)制的原因。這一研究成果發(fā)表在最新一期美國(guó)《公共科學(xué)圖書館·病原體》（PLoS Pathogens）雜志上,。
一般情況下,，流感病毒要實(shí)現(xiàn)從宿主細(xì)胞進(jìn)入包括人在內(nèi)的哺乳動(dòng)物體內(nèi)并進(jìn)行有效復(fù)制，其PB2蛋白質(zhì)的特定位置上需要存在兩種氨基酸——賴氨酸和天冬酰胺酸,。一直以來(lái),，研究人員并未在甲型流感病毒PB2蛋白質(zhì)的這一特定位置上發(fā)現(xiàn)這兩種氨基酸，因此對(duì)甲型H1N1流感能在人際間傳播感到費(fèi)解,。
研究小組發(fā)現(xiàn),，甲型流感病毒是過(guò)去90年中出現(xiàn)的4種禽流感和豬流感病毒“雜交”的產(chǎn)物，它甚至還包含1918年西班牙流感病毒的部分殘余,，其賴氨酸存在于PB2蛋白質(zhì)的另一特殊位置,。甲型流感病毒的這種特殊結(jié)構(gòu)使其能很好地適應(yīng)人體細(xì)胞，從而在人體內(nèi)有效復(fù)制,。
研究人員表示,，這一發(fā)現(xiàn)為預(yù)測(cè)將來(lái)的流感大流行提供了另一可用的遺傳標(biāo)記。（生物谷Bioon.com）
生物谷推薦原文出處：
PLoS Pathog 6(8): e1001034. doi:10.1371/journal.ppat.1001034
Biological and Structural Characterization of a Host-Adapting Amino Acid in Influenza Virus
Shinya Yamada1, Masato Hatta2, Bart L. Staker3,4, Shinji Watanabe2, Masaki Imai2, Kyoko Shinya5, Yuko Sakai-Tagawa1, Mutsumi Ito1, Makoto Ozawa2,6, Tokiko Watanabe2, Saori Sakabe1,7, Chengjun Li2, Jin Hyun Kim2, Peter J. Myler4,8,9, Isabelle Phan4,8, Amy Raymond3,4, Eric Smith3,4, Robin Stacy4,8, Chairul A. Nidom10,11, Simon M. Lank12, Roger W. Wiseman12, Benjamin N. Bimber12, David H. O'Connor12,13, Gabriele Neumann2, Lance J. Stewart3,4*, Yoshihiro Kawaoka1,2,5,6,7,14*
1 Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan, 2 Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America, 3 Emerald BioStructures, Inc., Bainbridge Island, Washington, United States of America, 4 Seattle Structural Genomics Center for Infectious Disease, Washington, United States of America, 5 Department of Microbiology and Infectious Diseases, Kobe University, Hyogo, Japan, 6 Department of Special Pathogens, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan, 7 ERATO Infection-Induced Host Responses Project, Saitama, Japan, 8 Seattle Biomedical Research Institute, Seattle, Washington, United States of America, 9 Departments of Global Health and Medical Education & Biomedical Informatics, University of Washington, Seattle, Washington, United States of America, 10 Faculty of Veterinary Medicine, Tropical Disease Centre, Airlangga University, Surabaya, Indonesia, 11 Collaborating Research Center-Emerging and Reemerging Infectious Diseases, Tropical Disease Centre, Airlangga University, Surabaya, Indonesia, 12 Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America, 13 Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America, 14 Creative Research Initiative, Sousei, Hokkaido University, Sapporo, Japan
Two amino acids (lysine at position 627 or asparagine at position 701) in the polymerase subunit PB2 protein are considered critical for the adaptation of avian influenza A viruses to mammals. However, the recently emerged pandemic H1N1 viruses lack these amino acids. Here, we report that a basic amino acid at position 591 of PB2 can compensate for the lack of lysine at position 627 and confers efficient viral replication to pandemic H1N1 viruses in mammals. Moreover, a basic amino acid at position 591 of PB2 substantially increased the lethality of an avian H5N1 virus in mice. We also present the X-ray crystallographic structure of the C-terminus of a pandemic H1N1 virus PB2 protein. Arginine at position 591 fills the cleft found in H5N1 PB2 proteins in this area, resulting in differences in surface shape and charge for H1N1 PB2 proteins. These differences may affect the protein's interaction with viral and/or cellular factors, and hence its ability to support virus replication in mammals.
