Structure and dynamics of the nucleocapsid-binding domain of the Sendai virus phosphoprotein in solution.
The RNA-dependent RNA polymerase of the Sendai virus (SeV) consists of the large protein (L) and the phosphoprotein (P). P plays a crucial role in the enzyme by positioning L (which carries the polymerase activity) onto the matrix for transcription and replication formed by the RNA and the nucleoprotein, the N-RNA. P has a modular structure with distinct functional domains: an N-terminal domain involved in binding to N degrees (N that is not yet bound to RNA) and a C-terminal domain that carries the oligomerisation domain, the N-RNA binding domain and the L binding domain and that, combined with L, is active in transcription. Structural data have previously been obtained on the N-terminal domain and on the oligomerisation domain of P, but not yet on its N-RNA binding domain (also-called the X protein). Here we present an NMR and a small angle neutron scattering study of the SeV X protein. We show that this molecule presents two subdomains linked by an 11-residue linker, with the N-subdomain lacking a well-defined conformation. The 3D structure of the C-subdomain consists of three alpha-helices revealing an asymmetric charge distribution that may be important for binding to RNA-bound nucleoprotein. The structure of the entire C-terminal domain of P is modelled from its constituent parts in combination with small angle scattering data on this domain.
Institut de Biologie Structurale 'Jean-Pierre Ebel' (UMR 5075, CEA-CNRS-UJF), 38027 Grenoble cedex 1, France. Laurence.Blanchard@ibs.fr
Laurence
L
Blanchard
Nicolas
N
Tarbouriech
Martin
M
Blackledge
Peter
P
Timmins
Wilhelm P
WP
Burmeister
Rob W H
RW
Ruigrok
Dominique
D
Marion
D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019251:Nucleocapsid / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D029082:Sendai virus / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
D010750:Phosphoproteins; D014764:Viral Proteins