6dpj

Crystal Structure of Bacillus Halodurans Ribonuclease H1 K196A in Complex with an RNA/DNA Hybrid: Reaction in 4 mM Mn2+ and 200 mM K+ for 80 s at 21 C

spinqualitylabelsall models 6dpj, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6dpj is a 4 chain structure with sequence from Alkalihalobacillus halodurans and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: EDO, GOL, IOD, K, MN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RNH1_HALH5 Endonuclease that specifically degrades the RNA of RNA-DNA hybrids. Publication Abstract from PubMed Catalysis by members of the RNase H superfamily of enzymes is generally believed to require only two Mg(2+) ions that are coordinated by active-site carboxylates. By examining the catalytic process of Bacillus halodurans RNase H1 in crystallo, however, we found that the two canonical Mg(2+) ions and an additional K(+) failed to align the nucleophilic water for RNA cleavage. Substrate alignment and product formation required a second K(+) and a third Mg(2+), which replaced the first K(+) and departed immediately after cleavage. A third transient Mg(2+) has also been observed for DNA synthesis, but in that case it coordinates the leaving group instead of the nucleophile as in the case of the RNase H1 hydrolysis reaction. These transient cations have no contact with the enzymes. Other DNA and RNA enzymes that catalyze consecutive cleavage and strand-transfer reactions in a single active site may similarly require cation trafficking coordinated by the substrate. Cation trafficking propels RNA hydrolysis.,Samara NL, Yang W Nat Struct Mol Biol. 2018 Aug;25(8):715-721. doi: 10.1038/s41594-018-0099-4. Epub, 2018 Aug 3. PMID:30076410 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease 3D structures

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