Structural characterization of human aryl sulphotransferases

Brix, Lulu A.; Duggleby, Ronald G.; Gaedigk, Andrea; McManus, Michael E.

doi:10.1042/bj3370337

Cited by 30 publications

(37 citation statements)

References 32 publications

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“…The crystal structure includes bound PAP, two pNP molecules, and 154 water molecules. Alternate conformations are modeled for Glu 13 , Gln 35 , and Met 260 . The quality of the structure was assessed with PROCHECK (25) and WHATCHECK (26).…”

Section: Methodsmentioning

confidence: 99%

Structure of a Human Carcinogen-converting Enzyme, SULT1A1

Gamage

Duggleby

Barnett

et al. 2003

Journal of Biological Chemistry

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148

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Sulfonation catalyzed by sulfotransferase enzymes plays an important role in chemical defense mechanisms against various xenobiotics but also bioactivates carcinogens. A major human sulfotransferase, SULT1A1, metabolizes and/or bioactivates many endogenous compounds and is implicated in a range of cancers because of its ability to modify diverse promutagen and procarcinogen xenobiotics. The crystal structure of human SULT1A1 reported here is the first sulfotransferase structure complexed with a xenobiotic substrate. An unexpected finding is that the enzyme accommodates not one but two molecules of the xenobiotic model substrate p-nitrophenol in the active site. This result is supported by kinetic data for SULT1A1 that show substrate inhibition for this small xenobiotic. The extended active site of SULT1A1 is consistent with binding of diiodothyronine but cannot easily accommodate ␤-estradiol, although both are known substrates. This observation, together with evidence for a disorder-order transition in SULT1A1, suggests that the active site is flexible and can adapt its architecture to accept diverse hydrophobic substrates with varying sizes, shapes and flexibility. Thus the crystal structure of SULT1A1 provides the molecular basis for substrate inhibition and reveals the first clues as to how the enzyme sulfonates a wide variety of lipophilic compounds.Sulfonation is a widely distributed biological reaction catalyzed by members of the supergene family of enzymes called sulfotransferases (SULTs).1 SULTs utilize the sulfonate donor 3Ј-phosphoadenosine 5Ј-phosphosulfate (PAPS) to catalyze sulfonation, yielding PAP as the desulfonated product of the reaction. These enzymes modify the biological activities of a diverse range of compounds including neurotransmitters, hormones, and drugs. The reaction aids excretion of foreign chemicals but, in some cases, causes bioactivation of carcinogens and mutagens (1-3). SULTs are the focus of intense research in the fields of cancer, drug metabolism, and pharmacogenetics because genetic variation, particularly in isoenzyme SULT1A1, may predispose to lung cancers (4), protect against colorectal cancers (5), and affect the age of onset in breast cancer (6).To date, five distinct mammalian gene families for cytosolic SULTs (SULTs 1-5) have been identified (7), although SULT3 and SULT5 have not been found in humans (8). The most extensive group of the human cytosolic SULTs is the SULT1 family, which includes SULTs 1A1, 1A2, 1A3, 1B1, 1C1, 1C2, and 1E1. Each SULT has distinct substrate preferences but may also exhibit broad and overlapping substrate specificity to span the diversity of chemicals requiring sulfonation. For example, SULT1A3 catalyzes dopamine sulfonation but also accepts p-nitrophenol (pNP) with lower affinity (9, 10). SULT1A1, which shares 93% identity with SULT1A3, also sulfonates dopamine and pNP but with the reverse preference, and in addition it can sulfonate a wide range of hydrophobic molecules (Fig. 1) including xenobiotics and endogenous substrates 3,3Ј-diio...

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Section: Methodsmentioning

confidence: 99%

Structure of a Human Carcinogen-converting Enzyme, SULT1A1

Gamage

Duggleby

Barnett

et al. 2003

Journal of Biological Chemistry

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148

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“…When the Glu146 of SULT1A3 was mutated to the corresponding Ala in SULT1A1, the activity of the mutated enzyme was altered to that of SULT1A1 (40,41). Since the substrate-bound structure of SULT1A3 is not available, dopamine was modeled into the presumed substrate-binding pocket of the SULT1A3-PAP structure by positioning the acceptor group at the position of 3-phenolic group of the E2 molecule in the mEST pocket.…”

Section: Minireviewmentioning

confidence: 99%

Structure and Function of Sulfotransferases

Negishi

Pedersen

Petrotchenko

et al. 2001

Archives of Biochemistry and Biophysics

308

231

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Sulfotransferases (STs) catalyze the transfer reaction of the sulfate group from the ubiquitous donor 3 -phosphoadenosine 5 -phosphosulfate (PAPS) to an acceptor group of numerous substrates. This reaction, often referred to as sulfuryl transfer, sulfation, or sulfonation, is widely observed from bacteria to humans and plays a key role in various biological processes such as cell communication, growth and development, and defense. The cytosolic STs sulfate small molecules such as steroids, bioamines, and therapeutic drugs, while the Golgi-membrane counterparts sulfate large molecules including glucosaminylglycans and proteins. We have now solved the X-ray crystal structures of four cytosolic and one membrane ST. All five STs are globular proteins composed of a single ␣/␤ domain with the characteristic five-stranded ␤-sheet. The ␤-sheet constitutes the core of the Paps-binding and catalytic sites. Structural analysis of the PAPS-, PAP-, substrate-, and/or orthovanadate (VO 4 3؊ )-bound enzymes has also revealed the common molecular mechanism of the transfer reaction catalyzed by sulfotransferses. The X-ray crystal structures have opened a new era for the study of sulfotransferases.

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“…Despite recent efforts from several laboratories (7)(8)(9)(10)(11), there is still relatively scant information concerning the structure/ function relationships of cytosolic ST enzymes. As noted earlier, SULT1A3 and SULT1A1, which are Ͼ93% identical in amino acid sequence and yet display distinct substrate specificity and other properties, provide an excellent model for studies in this regard.…”

Section: Resultsmentioning

confidence: 99%

“…Fig. 1A) and yet vary widely in their substrate specificity and other properties (7)(8)(9). They have thus served as an ideal model system to study structure/function relationships in these proteins.…”

mentioning

confidence: 99%

Structure-Function Relationships in the Stereospecific and Manganese-dependent 3,4-Dihydroxyphenylalanine/ Tyrosine-sulfating Activity of Human Monoamine-form Phenol Sulfotransferase, SULT1A3

Pai

Oxendine

Sugahara

et al. 2003

Journal of Biological Chemistry

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The human monoamine-form phenol sulfotransferase (PST), SULT1A3, has a unique 3,4-dihydroxyphenylalanine (Dopa)/tyrosine-sulfating activity that is stereospecific for their D-form enantiomers and can be stimulated dramatically by Mn 2؉ . This activity is not present in the simple phenol-form PST, SULT1A1, which is otherwise >93% identical to SULT1A3 in amino acid sequence. The majority of the differences between these two proteins reside in two variable regions of their sequences. Through the characterization of chimeric PSTs where these two regions were exchanged between them, it was demonstrated that variable Region II of SULT1A3 is required for the stereospecificity of its Dopa/tyrosine-sulfating activity, whereas variable Region I of SULT1A3 is required for the stimulation by Mn 2؉ of this activity. Further studies using point-mutated SULT1A3s mutated at amino acid residues in these two regions and deletional mutants missing residues 84 -86 and 84 -90 implicate residue Glu-146 (in variable Region II of SULT1A3), as well as the presence of residues 84 -90 of variable Region I, in the stereospecificity in the absence of Mn 2؉ . Residue Asp-86 (in variable Region I of SULT1A3), on the other hand, is critical in the Mn 2؉ stimulation of the Dopa/tyrosine-sulfating activity of SULT1A3. A model is proposed, with reference to the reported x-ray crystal structure of SULT1A3, to explain how the normal role of SULT1A3 in dopamine regulation may be subverted in the presence of Mn 2؉ . These studies could be relevant in understanding the stereoselective action of SULT1A3 on chiral drugs.The sulfotransferases (STs), 1 which are ubiquitous in both plants and animals, catalyze the sulfation of hydroxyl or amino groups on a variety of target acceptor molecules (1, 2). These enzymes all use adenosine 3Ј-phosphate,5Ј-phosphosulfate (PAPS) as the sulfonyl group donor (3) and share sequences responsible for PAPS binding (4). Although the membranebound STs use proteins, glycolipids, and other macromolecules as acceptor substrates, the cytosolic STs sulfate smaller molecules and are part of the Phase II detoxification pathway for the biotransformation/excretion of drugs and xenobiotics (1, 2). Increasingly, the cytosolic STs have also been shown to be important in regulating the levels and/or activities of endogenous compounds such as thyroid and steroid hormones, catecholamines, and bile acids (5, 6).Based on their sequences, the cytosolic STs have been classified into several gene families (4). Two human cytosolic STs, the monoamine-form and the simple phenol-form phenol sulfotransferases, named SULT1A3 and SULT1A1, respectively (4), show an extensive (Ͼ93%) identity in their amino acid sequences (cf. Fig. 1A) and yet vary widely in their substrate specificity and other properties (7-9). They have thus served as an ideal model system to study structure/function relationships in these proteins. Examination of their aligned sequences revealed that most of the differences between SULT1A3 and SULT1A1 occur in two variable regions, ...

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Structural characterization of human aryl sulphotransferases

Cited by 30 publications

References 32 publications

Structure of a Human Carcinogen-converting Enzyme, SULT1A1

Structure of a Human Carcinogen-converting Enzyme, SULT1A1

Structure and Function of Sulfotransferases

Structure-Function Relationships in the Stereospecific and Manganese-dependent 3,4-Dihydroxyphenylalanine/ Tyrosine-sulfating Activity of Human Monoamine-form Phenol Sulfotransferase, SULT1A3

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