title: Structure and sequence analysis of influenza A virus nucleoprotein.
abstract: Influenza A virus nucleoprotein (NP) forms homo-oligomers and multiple copies of NP wrap around genomic RNA, along with a trimeric polymerase making up ribonucleoprotein (RNP) complex. Sequence comparison of more than 2500 influenza A NP showed that this protein contains 30.1 % of polymorphic residues. NP is composed of a head and a body domain and a tail loop/ linker region. The head domain is more conserved than the body domain, as revealed from the structure-based sequence alignment. NP oligomerization is mediated by the insertion of the non-polymorphic and structurally conserved tail loop of one NP molecule to a groove of another NP. The different form of NP oligomers is due to the flexibility of the polymorphic linkers that join the tail loop to the rest of the protein. The RNA binding property of NP is known to involve the protruding element and the flexible basic loop between the head and body domains, both having high degree of primary sequence conservation. To bind RNA, NP may first capture the RNA by the flexible basic loop and then the RNA is clamped by the protruding element.
authors.affiliation: Molecular Biotechnology Programme, Department of Biochemistry and Centre 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: Jia-Huai
authors.initials: JH
authors.lastname: Wang
authors.forename: Pang-Chui
authors.initials: PC
authors.lastname: Shaw
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D009980:Influenza A virus / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014758:Viral Core Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D016601:RNA-Binding Proteins; D014758:Viral Core Proteins