Structure of the influenza virus A H5N1 nucleoprotein: implications for RNA binding, oligomerization, and vaccine design.
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.
Ng
Andy Ka-Leung
AK
Department of Biochemistry and Center for Protein Science and Crystallography, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
Zhang
Hongmin
H
Tan
Kemin
K
Li
Zongli
Z
Liu
Jin-huan
JH
Chan
Paul Kay-Sheung
PK
Li
Sui-Mui
SM
Chan
Wood-Yee
WY
Au
Shannon Wing-Ngor
SW
Joachimiak
Andrzej
A
Walz
Thomas
T
Wang
Jia-Huai
JH
Shaw
Pang-Chui
PC
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
D000998:Antiviral Agents; D007252:Influenza Vaccines; D009698:Nucleoproteins; D014758:Viral Core Proteins; D012313:RNA