3nhh

Crystal structure of Staphylococcal nuclease variant V23E-L36K at cryogenic temperature

spinqualitylabelsall models 3nhh, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3nhh is a 1 chain structure with sequence from Staphylococcus aureus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: CA, THP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NUC_STAAU Enzyme that catalyzes the hydrolysis of both DNA and RNA at the 5' position of the phosphodiester bond. 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 An artificial charge pair buried in the hydrophobic core of staphylococcal nuclease was engineered by making the V23E and L36K substitutions. Buried individually, Glu-23 and Lys-36 both titrate with pKa values near 7. When buried together their pKa values appear to be normal. The ionizable moieties of the buried Glu-Lys pair are 2.6 A apart. The interaction between them at pH 7 is worth 5 kcal/mol. Despite this strong interaction, the buried Glu-Lys pair destabilizes the protein significantly because the apparent Coulomb interaction is sufficient to offset the dehydration of only one of the two buried charges. Save for minor reorganization of dipoles and water penetration consistent with the relatively high dielectric constant reported by the buried ion pair, there is no evidence that the presence of two charges in the hydrophobic interior of the protein induces any significant structural reorganization. The successful engineering of an artificial ion pair in a highly hydrophobic environment suggests that buried Glu-Lys pairs in dehydrated environments can be charged and that it is possible to engineer charge clusters that loosely resemble catalytic sites in a scaffold protein with high thermodynamic stability, without the need for specialized structural adaptations. Structural and thermodynamic consequences of burial of an artificial ion pair in the hydrophobic interior of a protein.,Robinson AC, Castaneda CA, Schlessman JL, Garcia-Moreno E B Proc Natl Acad Sci U S A. 2014 Aug 12;111(32):11685-90. doi:, 10.1073/pnas.1402900111. Epub 2014 Jul 29. PMID:25074910 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Staphylococcal nuclease 3D structures

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