title: Structure of the influenza virus A H5N1 nucleoprotein: implications for RNA binding, oligomerization, and vaccine design.
abstract: The threat of a pandemic outbreak of influenza virus A H5N1 has become a major concern worldwide. The nucleoprotein (NP) of the virus binds the RNA genome and acts as a key adaptor between the virus and the host cell. It, therefore, plays an important structural and functional role and represents an attractive drug target. Here, we report the 3.3-A crystal structure of H5N1 NP, which is composed of a head domain, a body domain, and a tail loop. Our structure resolves the important linker segments (residues 397-401, 429-437) that connect the tail loop with the remainder of the molecule and a flexible, basic loop (residues 73-91) located in an arginine-rich groove surrounding Arg150. Using surface plasmon resonance, we found the basic loop and arginine-rich groove, but mostly a protruding element containing Arg174 and Arg175, to be important in RNA binding by NP. We also used our crystal structure to build a ring-shaped assembly of nine NP subunits to model the miniribonucleoprotein particle previously visualized by electron microscopy. Our study of H5N1 NP provides insight into the oligomerization interface and the RNA-binding groove, which are attractive drug targets, and it identifies the epitopes that might be used for universal vaccine development.
authors.affiliation: Department of Biochemistry and Center for Protein Science and Crystallography, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: Andy Ka-Leung
authors.initials: AK
authors.lastname: Ng
authors.forename: Hongmin
authors.initials: H
authors.lastname: Zhang
authors.forename: Kemin
authors.initials: K
authors.lastname: Tan
authors.forename: Zongli
authors.initials: Z
authors.lastname: Li
authors.forename: Jin-huan
authors.initials: JH
authors.lastname: Liu
authors.forename: Paul Kay-Sheung
authors.initials: PK
authors.lastname: Chan
authors.forename: Sui-Mui
authors.initials: SM
authors.lastname: Li
authors.forename: Wood-Yee
authors.initials: WY
authors.lastname: Chan
authors.forename: Shannon Wing-Ngor
authors.initials: SW
authors.lastname: Au
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
authors.forename: Thomas
authors.initials: T
authors.lastname: Walz
authors.forename: Jia-Huai
authors.initials: JH
authors.lastname: Wang
authors.forename: Pang-Chui
authors.initials: PC
authors.lastname: Shaw
mesh_terms: D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology; D018360:Crystallography, X-Ray; D015195:Drug Design; D053124:Influenza A Virus, H5N1 Subtype / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology; D007252:Influenza Vaccines / Q000737:chemistry / Q000276:immunology; D008969:Molecular Sequence Data; D009698:Nucleoproteins / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology; D011487:Protein Conformation; D012313:RNA / Q000737:chemistry; D014758:Viral Core Proteins / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology
chemical_list: D000998:Antiviral Agents; D007252:Influenza Vaccines; D009698:Nucleoproteins; D014758:Viral Core Proteins; D012313:RNA