1jxb

I53A, a point mutant of the cysteine-free variant of E. coli Rnase HI

spinqualitylabelsall models 1jxb, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1jxb is a 1 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1f21, 1jl1 Activity: Ribonuclease H, with EC number 3.1.26.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [RNH_ECOLI] Endonuclease that specifically degrades the RNA of RNA-DNA hybrids. RNase H participates in DNA replication; it helps to specify the origin of genomic replication by suppressing initiation at origins other than the oriC locus; along with the 5'-3' exonuclease of pol1, it removes RNA primers from the Okazaki fragments of lagging strand synthesis; and it defines the origin of replication for ColE1-type plasmids by specific cleavage of an RNA preprimer.[HAMAP-Rule:MF_00042] 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 A point mutation (I53A) in the core of Escherichia coli RNase H* is known to destabilize both the native conformation (DeltaG(UN)) and the kinetic intermediate (DeltaG(UI)) by 2 kcal/mole. Here, we have used native-state hydrogen deuterium exchange to ask how this destabilization is propagated throughout the molecule. Stability parameters were obtained for individual residues in I53A and compared with those from the wild-type protein. A destabilization of 2 kcal/mole was observed in residues in the core but was not detected in the periphery of the molecule. These results are consistent with the localized destabilization of the core observed in the early intermediate of the kinetic folding pathway, supporting the resemblance of this kinetic intermediate to the partially unfolded form detected in the native state at equilibrium. A thermodynamic cycle also shows no interaction between Ile 53 and a residue in the periphery. There is, however, an increase in the number of denaturant-independent exchange events in the periphery of I53A, showing that effects of the point mutation are communicated to regions outside the core, although perhaps not through changes in stability. In sum, this work shows that localized regions within a protein can be destabilized independently. Furthermore, it implies a correspondence between the kinetic intermediate and the equilibrium PUF, as the magnitude and localization of the destabilization are the same in both. Propagation of a single destabilizing mutation throughout the Escherichia coli ribonuclease HI native state.,Spudich G, Lorenz S, Marqusee S Protein Sci. 2002 Mar;11(3):522-8. PMID:11847275 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease Temp

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