1z3c

Encephalitozooan cuniculi mRNA Cap (Guanine-N7) Methyltransferasein complexed with AzoAdoMet

spinqualitylabelsall models 1z3c, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1z3c is a 1 chain structure with sequence from Encephalitozoon cuniculi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: SA8 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MCES_ENCCU mRNA-capping methyltransferase that methylates the N7 position of the added guanosine to the 5'-cap structure of mRNAs. Binds RNA containing 5'-terminal GpppC. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The Encephalitozoon cuniculi mRNA cap (guanine N-7) methyltransferase Ecm1 has been characterized structurally but not biochemically. Here we show that purified Ecm1 is a monomeric protein that catalyzes methyl transfer from S-adenosylmethionine (AdoMet) to GTP. The reaction is cofactor-independent and optimal at pH 7.5. Ecm1 also methylates GpppA, GDP, and dGTP but not ATP, CTP, UTP, ITP, or m(7)GTP. The affinity of Ecm1 for the cap dinucleotide GpppA (K 0.1 mm) is higher than that for GTP (K(m) 1 mm) or GDP (K(m) 2.4 mm). Methylation of GTP by Ecm1 in the presence of 5 microm AdoMet is inhibited by the reaction product AdoHcy (IC(50) 4 microm) and by substrate analogs sinefungin (IC(50) 1.5 microm), aza-AdoMet (IC(50) 100 microm), and carbocyclic aza-AdoMet (IC(50) 35 microm). The crystal structure of an Ecm1.aza-AdoMet binary complex reveals that the inhibitor occupies the same site as AdoMet. Structure-function analysis of Ecm1 by alanine scanning and conservative substitutions identified functional groups necessary for methyltransferase activity in vivo. Amino acids Lys-54, Asp-70, Asp-78, and Asp-94, which comprise the AdoMet-binding site, and Phe-141, which contacts the cap guanosine, are essential for cap methyltransferase activity in vitro. Encephalitozoon cuniculi mRNA cap (guanine N-7) methyltransferase: methyl acceptor specificity, inhibition BY S-adenosylmethionine analogs, and structure-guided mutational analysis.,Hausmann S, Zheng S, Fabrega C, Schneller SW, Lima CD, Shuman S J Biol Chem. 2005 May 27;280(21):20404-12. Epub 2005 Mar 9. PMID:15760890 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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