1kop

NEISSERIA GONORRHOEAE CARBONIC ANHYDRASE

spinqualitylabelsall models 1kop, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1kop is a 2 chain structure with sequence from "diplococcus_gonorrhoeae"_(zopf_1885)_lehmann_and_neumann_1896 "diplococcus gonorrhoeae" (zopf 1885) lehmann and neumann 1896. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AZI, BME, SO4, ZN Activity: Carbonate dehydratase, with EC number 4.2.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [CAH_NEIGO] Reversible hydration of carbon dioxide. 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 The crystal structure of carbonic anhydrase from Neisseria gonorrhoeae has been solved to a resolution of 1.78 A by molecular replacement using human carbonic anhydrase II as a template. After refinement the R factor was 17.8% (Rfree=23.2%). There are two molecules per asymmetric unit (space group P21), but they have essentially identical structures. The fold of the N. gonorrhoeae enzyme is very similar to that of human isozyme II; 192 residues, 74 of which are identical in the two enzymes, have equivalent positions in the three-dimensional structures. This corresponds to 85% of the entire polypeptide chain of the bacterial enzyme. The only two cysteine residues in the bacterial enzyme, which has a periplasmic location in the cell, are connected by a disulfide bond. Most of the secondary structure elements present in human isozyme II are retained in N. gonorrhoeae carbonic anhydrase, but there are also differences, particularly in the few helical regions. Long deletions in the bacterial enzyme relative to human isozyme II have resulted in a considerable shortening of three surface loops. One of these deletions, corresponding to residues 128 to 139 in the human enzyme, leads to a widening of the entrance to the hydrophobic part of the active site cavity. Practically all the amino acid residues in the active site of human isozyme II are conserved in the N. gonorrhoeae enzyme and have similar structural positions. However, the imidazole ring of a histidine residue, which has been shown to function as a proton shuttle in the catalytic mechanism of the human enzyme, interacts with an extraneous entity, which has tentatively been identified as a 2-mercaptoethanol molecule from the crystallization medium. When this entity is removed by soaking the crystal in a different medium, the side-chain of His66 becomes quite mobile. The structure of a complex with the sulfonamide inhibitor, acetazolamide, has also been determined. Its position in the active site is very similar to that observed in human carbonic anhydrase II. Crystal structure of carbonic anhydrase from Neisseria gonorrhoeae and its complex with the inhibitor acetazolamide.,Huang S, Xue Y, Sauer-Eriksson E, Chirica L, Lindskog S, Jonsson BH J Mol Biol. 1998;283(1):301-10. PMID:9761692 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Carbonic anhydrase 3D structures

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