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Michael A. Kertesz - One of the best experts on this subject based on the ideXlab platform.
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1 3 a structure of arylsulfatase from pseudomonas aeruginosa establishes the catalytic mechanism of Sulfate Ester cleavage in the sulfatase family
Structure, 2001Co-Authors: Imke Boltes, Rixa Von Bulow, Thomas Dierks, Bernhard Schmidt, Kurt Von Figura, Michael A. Kertesz, Honorata Czapinska, Antje Kahnert, Isabel UsónAbstract:Abstract Background: Sulfatases constitute a family of enzymes with a highly conserved active site region including a Cα−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 Cα−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.
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Bacterial transporters for Sulfate and organosulfur compounds.
Research in Microbiology, 2001Co-Authors: Michael A. KerteszAbstract:Abstract Microorganisms require sulfur for growth, and obtain it either from inorganic Sulfate or from organosulfur compounds such as sulfonates, Sulfate Esters, or sulfur-containing amino acids. Transport of Sulfate into the cell is catalyzed either by ATP binding cassette (ABC)-type transporters (SulT family) or by major facilitator superfamily-type transporters (SulP family). By contrast, the sulfonate and Sulfate Ester transporters identified to date are all ABC-type systems, whose synthesis is tightly regulated by the sulfur supply to the cell, mediated by the CysB protein and other transcriptional regulators of the LysR-family.
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the sulfur regulated arylsulfatase gene cluster of pseudomonas aeruginosa a new member of the cys regulon
Journal of Bacteriology, 2000Co-Authors: Jorg Hummerjohann, Michael A. Kertesz, Sascha Laudenbach, Julia Retey, Thomas LeisingerAbstract:A gene cluster upstream of the arylsulfatase gene (atsA) in Pseudomonas aeruginosa was characterized and found to encode a putative ABC-type transporter, AtsRBC. Mutants with insertions in the atsR or atsB gene were unable to grow with hexyl-, octyl-, or nitrocatecholSulfate, although they grew normally with other sulfur sources, such as Sulfate, methionine, and aliphatic sulfonates. AtsRBC therefore constitutes a general Sulfate Ester transport system, and desulfurization of aromatic and medium-chain-length aliphatic Sulfate Esters occurs in the cytoplasm. Expression of the atsR and atsBCA genes was repressed during growth with Sulfate, cysteine, or thiocyanate. No expression of these genes was observed in the cysB mutant PAO-CB, and the ats genes therefore constitute an extension of the cys regulon in this species.
Allan D Butterfield - One of the best experts on this subject based on the ideXlab platform.
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opiate receptor binding properties of morphine dihydromorphine and codeine 6 o Sulfate Ester congeners
Bioorganic & Medicinal Chemistry Letters, 2006Co-Authors: Peter A Crooks, Santosh G Kottayil, Abeer M Alghananeem, Stephen R Byrn, Allan D ButterfieldAbstract:Abstract A series of 3-O-acyl-6-O-Sulfate Esters of morphine, dihydromorphine, N-methylmorphinium iodide, codeine, and dihydrocodeine were prepared and evaluated for their ability to bind to μ-, δ-, κ1-, κ2-, and κ3-opiate receptors. Several compounds exhibited good affinity for the μ-opiate receptor. Morphine-3-O-propionyl-6-O-Sulfate had four times greater affinity than morphine at the μ-opiate receptor and was the most selective compound at this receptor subtype.
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opiate receptor binding properties of morphine dihydromorphine and codeine 6 o Sulfate Ester congeners
Bioorganic & Medicinal Chemistry Letters, 2006Co-Authors: Peter A Crooks, Santosh G Kottayil, Abeer M Alghananeem, Stephen R Byrn, Allan D ButterfieldAbstract:A series of 3-O-acyl-6-O-Sulfate Esters of morphine, dihydromorphine, N-methylmorphinium iodide, codeine, and dihydrocodeine were prepared and evaluated for their ability to bind to mu-, delta-, kappa(1)-, kappa(2)-, and kappa(3)-opiate receptors. Several compounds exhibited good affinity for the mu-opiate receptor. Morphine-3-O-propionyl-6-O-Sulfate had four times greater affinity than morphine at the mu-opiate receptor and was the most selective compound at this receptor subtype.
Isabel Usón - One of the best experts on this subject based on the ideXlab platform.
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1 3 a structure of arylsulfatase from pseudomonas aeruginosa establishes the catalytic mechanism of Sulfate Ester cleavage in the sulfatase family
Structure, 2001Co-Authors: Imke Boltes, Rixa Von Bulow, Thomas Dierks, Bernhard Schmidt, Kurt Von Figura, Michael A. Kertesz, Honorata Czapinska, Antje Kahnert, Isabel UsónAbstract:Abstract Background: Sulfatases constitute a family of enzymes with a highly conserved active site region including a Cα−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 Cα−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.
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crystal structure of an enzyme substrate complex provides insight into the interaction between human arylsulfatase a and its substrates during catalysis
Journal of Molecular Biology, 2001Co-Authors: R Von Bulow, Bernhard Schmidt, Thomas Dierks, K Von Figura, Isabel UsónAbstract:Abstract Arylsulfatase A (ASA) belongs to the sulfatase family whose members carry a Cα-formylglycine that is post-translationally generated by oxidation of a conserved cysteine or serine residue. The crystal structures of two arylsulfatases, ASA and ASB, and kinetic studies on ASA mutants led to different proposals for the catalytic mechanism in the hydrolysis of Sulfate Esters. The structures of two ASA mutants that lack the functional Cα-formylglycine residue 69, in complex with a synthetic substrate, have been determined in order to unravel the reaction mechanism. The crystal structure of the inactive mutant C69A-ASA in complex with p-nitrocatechol Sulfate (pNCS) mimics a reaction intermediate during Sulfate Ester hydrolysis by the active enzyme, without the covalent bond to the key side-chain FGly69. The structure shows that the side-chains of lysine 123, lysine 302, serine 150, histidine 229, the main-chain of the key residue 69 and the divalent cation in the active center are involved in Sulfate binding. It is proposed that histidine 229 protonates the leaving alcoholate after hydrolysis. C69S-ASA is able to bind covalently to the substrate and hydrolyze it, but is unable to release the resulting Sulfate. Nevertheless, the resulting sulfation is low. The structure of C69S-ASA shows the serine side-chain in a single conformation, turned away from the position a substrate occupies in the complex. This suggests that the double conformation observed in the structure of wild-type ASA is more likely to correspond to a formylglycine hydrate than to a twofold disordered aldehyde oxo group, and accounts for the relative inertness of the C69S-ASA mutant. In the C69S-ASA-pNCS complex, the substrate occupies the same position as in the C69A-ASA-pNCS complex, which corresponds to the non-covalently bonded substrate. Based on the structural data, a detailed mechanism for Sulfate Ester cleavage is proposed, involving an aldehyde hydrate as the functional group.
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crystal structure of an enzyme substrate complex provides insight into the interaction between human arylsulfatase a and its substrates during catalysis
Journal of Molecular Biology, 2001Co-Authors: Rixa Von Bulow, Thomas Dierks, Bernhard Schmidt, Kurt Von Figura, Isabel UsónAbstract:Arylsulfatase A (ASA) belongs to the sulfatase family whose members carry a C-alpha-formylglycine that is post-translationally generated by oxidation of a conserved cysteine or serine residue. The crystal structures of two arylsulfatases, ASA and ASB, and kinetic studies on ASA mutants led to different proposals for the catalytic mechanism in the hydrolysis of Sulfate Esters. The structures of two ASA mutants that lack the functional C-alpha-formylglycine residue 69, in complex with a synthetic substrate, have been determined in order to unravel the reaction mechanism. The crystal structure of the inactive mutant C69A-ASA in complex with p-nitrocatechol Sulfate (pNCS) mimics a reaction intermediate during Sulfate Ester hydrolysis by the active enzyme, without the covalent bond to the key side-chain FGly69. The structure shows that the side-chains of lysine 123, lysine 302, serine 150, histidine 229, the main-chain of the key residue 69 and the divalent cation in the active center are involved in Sulfate binding. It is proposed that histidine 229 protonates the leaving alcoholate after hydrolysis. C69S-ASA is able to bind covalently to the substrate and hydrolyze it, but is unable to release the resulting Sulfate. Nevertheless, the resulting sulfation is low. The structure of C69S-ASA shows the serine side-chain in a single conformation, turned away from the position a substrate occupies in the complex. This suggests that the double conformation observed in the structure of wild-tips ASA is more likely to correspond to a formylglycine hydrate than to a twofold disordered aldehyde oxo group, and accounts for the relative inertness of the C69S-ASA mutant. In the C69S-ASA-pNCS complex, the substrate occupies the same position as in the C69A-ASA-pNCS complex, which corresponds to the noncovalently bonded substrate. Based on the structural data, a detailed mechanism for Sulfate Ester cleavage is proposed, involving an aldehyde hydrate as the functional group. (C) 2001 Academic Press.
H R Kim - One of the best experts on this subject based on the ideXlab platform.
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purification and characterization of arylsulfatase from sphingomonas sp as6330
Applied Microbiology and Biotechnology, 2004Co-Authors: J H Kim, D S Byun, J S Godber, Jiil Choi, W C Choi, H R KimAbstract:Arylsulfatase was purified from Sphingomonas sp. AS6330 through ionic exchange, hydrophobic- and gel-chromatographies. The purity increased 12,800-fold with approximately 19.1% yield against cell homogenate. The enzyme was a monomeric protein with apparent molecular weight of 62 kDa as determined by sodium dodecylSulfate-polyacrylamide gel electrophoresis, and 41 kDa as determined by gel filtration. The enzyme had optimum reaction conditions for hydrolysis of Sulfate Ester bonds in agar and p-nitrophenyl Sulfate (NPS) at pH 7.0 and 45°C, with a specific activity of 3.93 and 97.2 U, respectively. The enzyme showed higher activity towards agar than other Sulfated marine polysaccharides such as porphyran, fucoidan and carrageenan. The K m and V max of the enzyme for hydrolysis of NPS were 54.9 μM and 113 mM/min, respectively. With reaction of 200 g agar with 100 U arylsulfatase for 8 h at 45°C, gel strength increased 2.44-fold, and 97.7% of the Sulfate in the agar was hydrolyzed.
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purification and characterization of arylsulfatase from sphingomonas sp as6330
Applied Microbiology and Biotechnology, 2004Co-Authors: J H Kim, D S Byun, J S Godber, Jiil Choi, Wonchang Choi, H R KimAbstract:Arylsulfatase was purified from Sphingomonas sp. AS6330 through ionic exchange, hydrophobic- and gel-chromatographies. The purity increased 12,800-fold with approximately 19.1% yield against cell homogenate. The enzyme was a monomeric protein with apparent molecular weight of 62 kDa as determined by sodium dodecylSulfate-polyacrylamide gel electrophoresis, and 41 kDa as determined by gel filtration. The enzyme had optimum reaction conditions for hydrolysis of Sulfate Ester bonds in agar and p-nitrophenyl Sulfate (NPS) at pH 7.0 and 45 degrees C, with a specific activity of 3.93 and 97.2 U, respectively. The enzyme showed higher activity towards agar than other Sulfated marine polysaccharides such as porphyran, fucoidan and carrageenan. The K(m) and V(max) of the enzyme for hydrolysis of NPS were 54.9 microM and 113 mM/min, respectively. With reaction of 200 g agar with 100 U arylsulfatase for 8 h at 45 degrees C, gel strength increased 2.44-fold, and 97.7% of the Sulfate in the agar was hydrolyzed.
Hansjoachim Lehmler - One of the best experts on this subject based on the ideXlab platform.
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Estrogenicity and androgenicity screening of PCB Sulfate monoEsters in human breast cancer MCF-7 cells
Environmental Science and Pollution Research, 2016Co-Authors: Susanne Flor, Hansjoachim Lehmler, Gabriele LudewigAbstract:Recent studies identified polychlorinated biphenyl (PCB) Sulfate Esters as a major product of PCB metabolism. Since hydroxy-PCBs (HO-PCBs), the immediate precursors of PCB Sulfates and important contributors to PCB toxicity, were shown to have estrogenic activity, we investigated the estrogenicity/androgenicty of a series of PCB Sulfate metabolites. We synthesized the five possible structural Sulfate monoEster metabolites of PCB 3, a congener shown to be biotransformed to Sulfates, a Sulfate Ester of the paint-specific congener PCB 11, and Sulfate monoEsters of two HO-PCBs reported to interact with sulfotransferases (PCB 39, no ortho chlorines, and PCB 53, 3 ortho chlorines). We tested these PCB Sulfates and 4′-HO-PCB 3 as positive control for estrogenic, androgenic, anti-estrogenic, and anti-androgenic activity in the E- and A-screen with human breast cancer MCF7-derived cells at 100 μM–1 pM concentrations. Only 4′-HO-PCB 3 was highly cytotoxic at 100 μM. We observed structure-activity relationships: compounds with a Sulfate group in the chlorine-containing ring of PCB 3 (2PCB 3 and 3PCB 3 Sulfate) showed no interaction with the estrogen (ER) and androgen (AR) receptor. The 4′-HO-PCB 3 and its Sulfate Ester had the highest estrogenic effect, but at 100-fold different concentrations, i.e., 1 and 100 μM, respectively. Four of the PCB Sulfates were estrogenic (2′PCB 3, 4′PCB 3, 4′PCB 39, and 4′PCB 53 Sulfates; at 100 μM). These Sulfates and 3′PCB 3 Sulfate also exhibited anti-estrogenic activity, but at nM and pM concentrations. The 4′PCB 3 Sulfate ( para-para ′ substituted) had the strongest androgenic activity, followed by 3′PCB 3, 4′PCB 53, 4PCB11, and 4PCB 39 Sulfates and the 4′HO-PCB 3. In contrast, anti-androgenicity was only observed with the two compounds that have the Sulfate group in ortho- or meta- position in the second ring (2′PCB 3 and 3′PCB 3 Sulfate). No dose–response was observed in any screen, but, with exception of estrogenic activity (only seen at 100 μM), endocrine activity was often displayed at several concentrations and even at 1 pM concentration. These data suggest that sulfation of HO-PCBs is indeed reducing their cytotoxicity and estrogenicity, but may produce other endocrine disruptive activities at very low concentrations.
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4 chloro biphenyl 3 yl 2 2 2 trichloro ethyl Sulfate
Acta Crystallographica Section E-structure Reports Online, 2010Co-Authors: Xueshu Li, Sean Parkin, Michael W Duffel, Larry W Robertson, Hansjoachim LehmlerAbstract:The title compound, C14H10Cl4O4S, is a 2,2,2-trichloroethyl-protected precursor of 4′-chlorobiphenyl-3-yl Sulfate, a sulfuric acid Ester of 4′-chlorobiphenyl-3-ol. The Caromatic—O and O—S bond lengths of the Caromatic—O—S unit are comparable to those in structurally analogous biphenyl-4-yl 2,2,2-trichloroethyl Sulfates with no electronegative chlorine substituent in the benzene ring with the Sulfate Ester group. The dihedral angle between the aromatic rings is 27.47 (6)°.
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4′-Chlorobiphenyl-3-yl 2,2,2-trichloroethyl Sulfate
International Union of Crystallography, 2010Co-Authors: Sean Parkin, Michael W Duffel, Larry W Robertson, Hansjoachim LehmlerAbstract:The title compound, C14H10Cl4O4S, is a 2,2,2-trichloroethyl-protected precursor of 4′-chlorobiphenyl-3-yl Sulfate, a sulfuric acid Ester of 4′-chlorobiphenyl-3-ol. The Caromatic—O and O—S bond lengths of the Caromatic—O—S unit are comparable to those in structurally analogous biphenyl-4-yl 2,2,2-trichloroethyl Sulfates with no electronegative chlorine substituent in the benzene ring with the Sulfate Ester group. The dihedral angle between the aromatic rings is 27.47 (6)°
