4hdg

Crystal Structure of viral RdRp in complex with GTP

spinqualitylabelsall models 4hdg, resolution 2.38Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4hdg is a 2 chain structure with sequence from Japanese encephalitis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GTP, ZN Related: 4hdh Activity: RNA-directed RNA polymerase, with EC number 2.7.7.48 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [G3LHD9_9FLAV] Envelope protein E binding to host cell surface receptor is followed by virus internalization through clathrin-mediated endocytosis. Envelope protein E is subsequently involved in membrane fusion between virion and host late endosomes. Synthesized as a homodimer with prM which acts as a chaperone for envelope protein E. After cleavage of prM, envelope protein E dissociate from small envelope protein M and homodimerizes (By similarity).[SAAS:SAAS000336_004_099774] Publication Abstract from PubMed Flaviviral RNA-dependent RNA polymerases (RdRps) initiate replication of the single-stranded RNA genome in the absence of a primer. The template sequence 5'-CU-3' at the 3'-end of the flaviviral genome is highly conserved. Surprisingly, flaviviral RdRps require high concentrations of the second incoming nucleotide GTP to catalyze de novo template-dependent RNA synthesis. We show that GTP stimulates de novo RNA synthesis by RdRp from Japanese encephalitis virus (jRdRp) also. Crystal structures of jRdRp complexed with GTP and ATP provide a basis for specific recognition of GTP. Comparison of the jRdRpGTP structure with other viral RdRp-GTP structures shows that GTP binds jRdRp in a novel conformation. Apo-jRdRp structure suggests that the conserved motif F of jRdRp occupies multiple conformations in absence of GTP. Motif F becomes ordered on GTP binding and occludes the nucleotide triphosphate entry tunnel. Mutational analysis of key residues that interact with GTP evinces that the jRdRpGTP structure represents a novel pre-initiation state. Also, binding studies show that GTP binding reduces affinity of RdRp for RNA, but the presence of the catalytic Mn2+ ion abolishes this inhibition. Collectively, these observations suggest that the observed pre-initiation state may serve as a checkpoint to prevent erroneous template-independent RNA synthesis by jRdRp during initiation. RNA-dependent RNA polymerase of Japanese encephalitis virus binds the initiator nucleotide GTP to form a mechanistically important pre-initiation state.,Surana P, Satchidanandam V, Nair DT Nucleic Acids Res. 2013 Nov 28. PMID:24293643 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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