The structure of a protein primer-polymerase complex in the initiation of genome replication.
Picornavirus RNA replication is initiated by the covalent attachment of a UMP molecule to the hydroxyl group of a tyrosine in the terminal protein VPg. This reaction is carried out by the viral RNA-dependent RNA polymerase (3D). Here, we report the X-ray structure of two complexes between foot-and-mouth disease virus 3D, VPg1, the substrate UTP and divalent cations, in the absence and in the presence of an oligoadenylate of 10 residues. In both complexes, VPg fits the RNA binding cleft of the polymerase and projects the key residue Tyr3 into the active site of 3D. This is achieved by multiple interactions with residues of motif F and helix alpha8 of the fingers domain and helix alpha13 of the thumb domain of the polymerase. The complex obtained in the presence of the oligoadenylate showed the product of the VPg uridylylation (VPg-UMP). Two metal ions and the catalytic aspartic acids of the polymerase active site, together with the basic residues of motif F, have been identified as participating in the priming reaction.
Ferrer-Orta
Cristina
C
Institut de Biologia Molecular de Barcelona (CSIC), Parc Científic de Barcelona, Barcelona, Spain.
Arias
Armando
A
Agudo
Rubén
R
Pérez-Luque
Rosa
R
Escarmís
Cristina
C
Domingo
Esteban
E
Verdaguer
Nuria
N
D018360:Crystallography, X-Ray; D029544:Foot-and-Mouth Disease Virus / Q000737:chemistry* / Q000378:metabolism; D009843:Oligoribonucleotides / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012367:RNA, Viral / Q000096:biosynthesis / Q000737:chemistry*; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry* / Q000378:metabolism; D014544:Uridine Triphosphate / Q000737:chemistry* / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism; D014779:Virus Replication / Q000502:physiology
D009843:Oligoribonucleotides; D012367:RNA, Viral; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase; D014544:Uridine Triphosphate