1gn6

G152A mutant of Mycobacterium tuberculosis iron-superoxide dismutase.

spinqualitylabelsall models 1gn6, resolution 2.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1gn6 is a 4 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.9Å Ligands: FE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SODF_MYCTU Destroys superoxide anion radicals which are normally produced within the cells and which are toxic to biological systems. 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 We have refined the X-ray structure of a site-directed G152A mutant of the iron-dependent superoxide dismutase from Mycobacterium tuberculosis at 2.9 angstroms resolution. The mutation which replaces a glycine residue in a surface loop with alanine was designed to alter the conformation of this loop region which has previously been shown to play a crucial structural role in quaternary interactions within the SOD tetramer. Gly-152 was targeted as it has dihedral angles (phi = 83.1 degrees, psi = -0.3 degrees) close to the left-handed alpha-helical conformation which is rarely adopted by other amino acids except asparagine. Gly-152 was replaced by alanine as it has similar size and polarity, yet has a very low tendency to adopt similar conformations. X-ray data collection on crystals of this mutant at 2.9 angstroms resolution and subsequent least-squares refinement to an R-value of 0.169 clearly establish that the loop conformation is unaffected. Fluorescence studies of guanidine hydrochloride denaturation establish that the mutant is 4 kcal/mol less stable than the wild-type enzyme. Our results indicate that strict conformational constraints imposed upon a region of polypeptide, due for example to interactions with a neighbouring subunit, may force an alanine residue to adopt this sterically hindered conformation with a consequent reduction in stability of the folded conformation. X-ray structure analysis of an engineered Fe-superoxide dismutase Gly-Ala mutant with significantly reduced stability to denaturant.,Cooper JB, Saward S, Erskine PT, Badasso MO, Wood SP, Zhang Y, Young D FEBS Lett. 1996 Jun 3;387(2-3):105-8. PMID:8674528 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Superoxide dismutase 3D structures

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