2e4l
From Proteopedia
Thermodynamic and Structural Analysis of Thermolabile RNase HI from Shewanella oneidensis MR-1
Structural highlights
FunctionRNH_SHEON Endonuclease that specifically degrades the RNA of RNA-DNA hybrids (By similarity). Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedRibonuclease (RNase) HI from the psychrotrophic bacterium Shewanella oneidensis MR-1 was overproduced in Escherichia coli, purified, and structurally and biochemically characterized. The amino acid sequence of MR-1 RNase HI is 67% identical to that of E. coli RNase HI. The crystal structure of MR-1 RNase HI determined at 2.0 A resolution was highly similar to that of E. coli RNase HI, except that the number of intramolecular ion pairs and the fraction of polar surface area of MR-1 RNase HI were reduced compared to those of E. coli RNase HI. The enzymatic properties of MR-1 RNase HI were similar to those of E. coli RNase HI. However, MR-1 RNase HI was much less stable than E. coli RNase HI. The stability of MR-1 RNase HI against heat inactivation was lower than that of E. coli RNase HI by 19 degrees C. The conformational stability of MR-1 RNase HI was thermodynamically analyzed by monitoring the CD values at 220 nm. MR-1 RNase HI was less stable than E. coli RNase HI by 22.4 degrees C in Tm and 12.5 kJ/mol in DeltaG(H2O). The thermodynamic stability curve of MR-1 RNase HI was characterized by a downward shift and increased curvature, which results in an increased DeltaCp value, compared to that of E. coli RNase HI. Site-directed mutagenesis studies suggest that the difference in the number of intramolecular ion pairs partly accounts for the difference in stability between MR-1 and E. coli RNases HI. Structural, thermodynamic, and mutational analyses of a psychrotrophic RNase HI.,Tadokoro T, You DJ, Abe Y, Chon H, Matsumura H, Koga Y, Takano K, Kanaya S Biochemistry. 2007 Jun 26;46(25):7460-8. Epub 2007 May 31. PMID:17536836[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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