1ql0
Sm Endonuclease from Seratia marcenscens at atomic resolution
Structural highlights
FunctionNUCA_SERMA Catalyzes the hydrolysis of both DNA and RNA, double- or single-stranded, at the 3'position of the phosphodiester bond to produce 5'-phosphorylated mono-, di-, tri- and tetranucleotides. DNA is a slightly better substrate than RNA. 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 PubMedThe three-dimensional crystal structure of Serratia marcescens endonuclease has been refined at 1.1 A resolution to an R factor of 12.9% and an R(free) of 15.6% with the use of anisotropic temperature factors. The model contains 3694 non-H atoms, 715 water molecules, four sulfate ions and two Mg(2+)-binding sites at the active sites of the homodimeric protein. It is shown that the magnesium ion linked to the active-site Asn119 of each monomer is surrounded by five water molecules and shows an octahedral coordination geometry. The temperature factors for the bound Mg(2+) ions in the A and B subunits are 7.08 and 4.60 A(2), respectively, and the average temperature factors for the surrounding water molecules are 12.13 and 10.3 A(2), respectively. In comparison with earlier structures, alternative side-chain conformations are defined for 51 residues of the dimer, including the essential active-site residue Arg57. A plausible mechanism of enzyme function is proposed based on the high-resolution S. marcescens nuclease structure, the functional characteristics of the natural and mutational forms of the enzyme and consideration of its structural analogy with homing endo-nuclease I-PpoI. Atomic structure of the Serratia marcescens endonuclease at 1.1 A resolution and the enzyme reaction mechanism.,Shlyapnikov SV, Lunin VV, Perbandt M, Polyakov KM, Lunin VY, Levdikov VM, Betzel C, Mikhailov AM Acta Crystallogr D Biol Crystallogr. 2000 May;56(Pt 5):567-72. PMID:10771425[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
