A 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-β-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.
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http://dx.doi.org/10.1111/febs.12027 | DOI Listing |
Appl Environ Microbiol
December 2019
Westfälische Wilhelms-Universität Münster, Institut für Molekulare Mikrobiologie und Biotechnologie, Münster, Germany
Bacteria using toxic chemicals, such as detergents, as growth substrates face the challenge of exposing themselves to cell-damaging effects that require protection mechanisms, which demand energy delivered from catabolism of the toxic compound. Thus, adaptations are necessary for ensuring the rapid onset of substrate degradation and the integrity of the cells. strain PAO1 can use the toxic detergent sodium dodecyl sulfate (SDS) as a growth substrate and employs, among others, cell aggregation as a protection mechanism.
View Article and Find Full Text PDFFront Microbiol
August 2018
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Biochemical, physiological and genomic comparisons of two strains, assigned previously to the subgroup, which are efficient SDS-degraders were carried out. A GO enrichment analysis showed that the genomes of SDS-degraders encode more genes connected with bacterial cell wall biosynthesis and alkanesulfonate monooxygenase activity than their closest relatives from the subgroup. A transcriptomic analysis of the most promising strain exposed to detergent suggests that although SDS can be later utilized as a carbon source, in early stages it influences cell envelope integrity, causing a global stress response followed by cell wall modification and induction of repair mechanisms.
View Article and Find Full Text PDFFront Microbiol
November 2017
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Due to their particular properties, detergents are widely used in household cleaning products, cosmetics, pharmaceuticals, and in agriculture as adjuvants tailoring the features of pesticides or other crop protection agents. The continuously growing use of these various products means that water soluble detergents have become one of the most problematic groups of pollutants for the aquatic and terrestrial environments. Thus it is important to identify bacteria having the ability to survive in the presence of large quantities of detergent and efficiently decompose it to non-surface active compounds.
View Article and Find Full Text PDFBiosci Rep
June 2017
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
A novel alkylsulfatase from bacterium (SdsAP) was identified as a thermostable alkylsulfatases (type III), which could hydrolyze the primary alkyl sulfate such as sodium dodecyl sulfate (SDS). Thus, it has a potential application of SDS biodegradation. The crystal structure of SdsAP has been solved to a resolution of 1.
View Article and Find Full Text PDFJ Appl Microbiol
March 2016
School of Biosciences, Mahatma Gandhi University, Kottayam, India.
Aims: Biological synthesis of rhamnolipids from SDS by Pseudomonas aeruginosa S15 is found to be a cost effective mode of rhamnolipid synthesis. This study aimed to attempt rhamnolipid synthesis by transformant Escherichia coli DH5α cells.
Methods And Results: Molecular analysis by curing experiments revealed that the properties of SDS based rhamnolipid synthesis were plasmid borne.
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