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| {{STRUCTURE_1hdh| PDB=1hdh | SCENE= }} | | {{STRUCTURE_1hdh| PDB=1hdh | SCENE= }} |
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| '''ARYLSULFATASE FROM PSEUDOMONAS AERUGINOSA'''
| | ===ARYLSULFATASE FROM PSEUDOMONAS AERUGINOSA=== |
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| ==Overview==
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| BACKGROUND: Sulfatases constitute a family of enzymes with a highly conserved active site region including a Calpha-formylglycine that is posttranslationally generated by the oxidation of a conserved cysteine or serine residue. The crystal structures of two human arylsulfatases, ASA and ASB, along with ASA mutants and their complexes led to different proposals for the catalytic mechanism in the hydrolysis of sulfate esters. RESULTS: The crystal structure of a bacterial sulfatase from Pseudomonas aeruginosa (PAS) has been determined at 1.3 A. Fold and active site region are strikingly similar to those of the known human sulfatases. The structure allows a precise determination of the active site region, unequivocally showing the presence of a Calpha-formylglycine hydrate as the key catalytic residue. Furthermore, the cation located in the active site is unambiguously characterized as calcium by both its B value and the geometry of its coordination sphere. The active site contains a noncovalently bonded sulfate that occupies the same position as the one in para-nitrocatecholsulfate in previously studied ASA complexes. CONCLUSIONS: The structure of PAS shows that the resting state of the key catalytic residue in sulfatases is a formylglycine hydrate. These structural data establish a mechanism for sulfate ester cleavage involving an aldehyde hydrate as the functional group that initiates the reaction through a nucleophilic attack on the sulfur atom in the substrate. The alcohol is eliminated from a reaction intermediate containing pentacoordinated sulfur. Subsequent elimination of the sulfate regenerates the aldehyde, which is again hydrated. The metal cation involved in stabilizing the charge and anchoring the substrate during catalysis is established as calcium.
| | The line below this paragraph, {{ABSTRACT_PUBMED_11435113}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 11435113 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_11435113}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Formylglycine hydrate]] | | [[Category: Formylglycine hydrate]] |
| [[Category: Sulfatase]] | | [[Category: Sulfatase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:43:55 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 08:02:02 2008'' |