4axh
From Proteopedia
Structure and mechanism of the first inverting alkylsulfatase specific for secondary alkylsulfatases
Structural highlights
FunctionRSAKS_PSESP Alkylsulfatase that catalyzes the enantioselective hydrolysis of secondary-alkylsulfates with strict inversion of configuration, leading to the formation of homochiral (S)-configurated alcohols and nonreacted sulfate esters (PubMed:21770430, Ref.2, PubMed:23061549). The substrate spectrum includes a range of linear, branched or cyclic sec-alkylsulfates (PubMed:21770430). Can use sec-alkylsulfate esters bearing aromatic, olefinic and acetylenic moieties (Ref.2). Acts by cleaving the C-O bond, resulting in inversion at the carbon (PubMed:23061549).[1] [2] [3] Publication Abstract from PubMedA highly enantioselective and stereoselective secondary alkylsulfatase from Pseudomonas sp. DSM6611 (Pisa1) was heterologously expressed in Escherichia coli BL21, and purified to homogeneity for kinetic and structural studies. Structure determination of Pisa1 by X-ray crystallography showed that the protein belongs to the family of metallo-beta-lactamases with a conserved binuclear Zn(2+) cluster in the active site. In contrast to a closely related alkylsulfatase from Pseudomonas aeruginosa (SdsA1), Pisa1 showed a preference for secondary rather than primary alkyl sulfates, and enantioselectively hydrolyzed the (R)-enantiomer of rac-2-octyl sulfate, yielding (S)-2-octanol with inversion of absolute configuration as a result of C-O bond cleavage. In order to elucidate the mechanism of inverting sulfate ester hydrolysis, for which no counterpart in chemical catalysis exists, we designed variants of Pisa1 guided by three-dimensional structure and docking experiments. In the course of these studies, we identified an invariant histidine (His317) near the sulfate-binding site as the general acid for crucial protonation of the sulfate leaving group. Additionally, amino acid replacements in the alkyl chain-binding pocket generated an enzyme variant that lost its stereoselectivity towards rac-2-octyl sulfate. These findings are discussed in light of the potential use of this enzyme family for applications in biocatalysis. DATABASE: The atomic coordinates and structural factors have been deposited in the Protein Data Bank under the accession codes 2YHE (wild type, crystal form I), 4AV7 (double variant Ser233-->Tyr/Ph250-->Gly) and 4AXH (wild type, crystal form II) STRUCTURED DIGITAL ABSTRACT: Pisa1 and Pisa1 bind by x-ray crystallography (View interaction). Structure and mechanism of an inverting alkylsulfatase from Pseudomonas sp. DSM6611 specific for secondary alkyl sulfates.,Knaus T, Schober M, Kepplinger B, Faccinelli M, Pitzer J, Faber K, Macheroux P, Wagner U FEBS J. 2012 Dec;279(23):4374-84. doi: 10.1111/febs.12027. Epub 2012 Nov 7. PMID:23061549[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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