1eke

CRYSTAL STRUCTURE OF CLASS II RIBONUCLEASE H (RNASE HII) WITH MES LIGAND

spinqualitylabelsall models 1eke, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1eke is a 2 chain structure with sequence from Methanocaldococcus jannaschii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: MES, MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN Function RNH2_METJA Endonuclease that specifically degrades the RNA of RNA-DNA hybrids.[HAMAP-Rule:MF_00052_A] 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 BACKGROUND: RNases H are present in all organisms and cleave RNAs in RNA/DNA hybrids. There are two major types of RNases H that have little similarity in sequence, size and specificity. The structure of RNase HI, the smaller enzyme and most abundant in bacteria, has been extensively studied. However, no structural information is available for the larger RNase H, which is most abundant in eukaryotes and archaea. Mammalian RNase H participates in DNA replication, removal of the Okazaki fragments and possibly DNA repair. RESULTS: The crystal structure of RNase HII from the hypothermophile Methanococcus jannaschii, which is homologous to mammalian RNase H, was solved using a multiwavelength anomalous dispersion (MAD) phasing method at 2 A resolution. The structure contains two compact domains. Despite the absence of sequence similarity, the large N-terminal domain shares a similar fold with the RNase HI of bacteria. The active site of RNase HII contains three aspartates: Asp7, Asp112 and Asp149. The nucleotide-binding site is located in the cleft between the N-terminal and C-terminal domains. CONCLUSIONS: Despite a lack of any detectable similarity in primary structure, RNase HII shares a similar structural domain with RNase HI, suggesting that the two classes of RNases H have a common catalytic mechanism and possibly a common evolutionary origin. The involvement of the unique C-terminal domain in substrate recognition explains the different reaction specificity observed between the two classes of RNase H. Crystal structure of archaeal RNase HII: a homologue of human major RNase H.,Lai L, Yokota H, Hung LW, Kim R, Kim SH Structure. 2000 Aug 15;8(8):897-904. PMID:10997908 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease 3D structures

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