3s24 | pdb_00003s24

Crystal structure of human mRNA guanylyltransferase

spinqualitylabelsall models 3s24, resolution 3.01Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3s24 is a 7 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4 Related: 1ckm, 1ckn, 1cko, 1p16, 2c46 Gene: RNGTT, CAP1A (HUMAN) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [MCE1_HUMAN] Bifunctional mRNA-capping enzyme exhibiting RNA 5'-triphosphatase activity in the N-terminal part and mRNA guanylyltransferase activity in the C-terminal part. Catalyzes the first two steps of cap formation: by removing the gamma-phosphate from the 5'-triphosphate end of nascent mRNA to yield a diphosphate end, and by transferring the gmp moiety of GTP to the 5'-diphosphate terminus. Publication Abstract from PubMed The enzyme guanylyltransferase (GTase) plays a central role in the three-step catalytic process of adding an (m7)GpppN cap cotranscriptionally to nascent mRNA (pre-mRNAs). The 5'-mRNA capping process is functionally and evolutionarily conserved from unicellular organisms to human. However, the GTases from viruses and yeast have low amino acid sequence identity ( approximately 25%) with GTases from mammals that, in contrast, are highly conserved ( approximately 98%). We have defined by limited proteolysis of human capping enzyme residues 229-567 as comprising the minimum enzymatically active human GTase (hGTase) domain and have determined the structure by X-ray crystallography. Seven related conformational states of hGTase exist in the crystal. The GTP-binding site is evolutionarily and structurally conserved. The positional variations of the oligonucleotide/oligosaccharide binding fold lid domain over the GTP-binding site provide snapshots of the opening and closing of the active site cleft through a swivel motion. The pattern of conserved surface residues in mammals, but not in yeast, supports the finding that the recognition of the capping apparatus by RNA polymerase II and associated transcription factors is highly conserved in mammals, and the mechanism may differ somewhat from that in yeast. The hGTase structure should help in the design of biochemical and molecular biology experiments to explore the proteinprotein and proteinRNA interactions that ensure regulated transcription of genes in humans and other mammals. Structure of the guanylyltransferase domain of human mRNA capping enzyme.,Chu C, Das K, Tyminski JR, Bauman JD, Guan R, Qiu W, Montelione GT, Arnold E, Shatkin AJ Proc Natl Acad Sci U S A. 2011 Jun 2. PMID:21636784 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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