3otc

Crystal structure of human tRNAHis guanylyltransferase (Thg1)- Native II

spinqualitylabelsall models 3otc, resolution 3.01Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3otc is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 3otb, 3otd, 3ote Gene: ICF45, THG1L (Homo sapiens) Resources: FirstGlance, OCA, RCSB, PDBsum Function [THG1_HUMAN] Adds a GMP to the 5'-end of tRNA(His) after transcription and RNase P cleavage. This step is essential for proper recognition of the tRNA and for the fidelity of protein synthesis. Publication Abstract from PubMed All known DNA and RNA polymerases catalyze the formation of phosphodiester bonds in a 5' to 3' direction, suggesting this property is a fundamental feature of maintaining and dispersing genetic information. The tRNA(His) guanylyltransferase (Thg1) is a member of a unique enzyme family whose members catalyze an unprecedented reaction in biology: 3'-5' addition of nucleotides to nucleic acid substrates. The 2.3-A crystal structure of human THG1 (hTHG1) reported here shows that, despite the lack of sequence similarity, hTHG1 shares unexpected structural homology with canonical 5'-3' DNA polymerases and adenylyl/guanylyl cyclases, two enzyme families known to use a two-metal-ion mechanism for catalysis. The ability of the same structural architecture to catalyze both 5'-3' and 3'-5' reactions raises important questions concerning selection of the 5'-3' mechanism during the evolution of nucleotide polymerases. tRNAHis guanylyltransferase (THG1), a unique 3'-5' nucleotidyl transferase, shares unexpected structural homology with canonical 5'-3' DNA polymerases.,Hyde SJ, Eckenroth BE, Smith BA, Eberley WA, Heintz NH, Jackman JE, Doublie S Proc Natl Acad Sci U S A. 2010 Nov 8. PMID:21059936 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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