A nucleotide-gated molecular pore selects sulfotransferase substrates

Ian T. Cook, Ting Wang, Charles N. Falany, Thomas S. Leyh

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Human SULT2A1 is one of two predominant sulfotransferases in liver and catalyzes transfer of the sulfuryl moiety (-SO3) from activated sulfate (PAPS, 3′-phosphoadenosine 5-phosphosulfate) to hundreds of acceptors (metabolites and xenobiotics). Sulfation recodes the biologic activity of acceptors by altering their receptor interactions. The molecular basis on which these enzymes select and sulfonate specific acceptors from complex mixtures of competitors in vivo is a long-standing issue in the SULT field. Raloxifene, a synthetic steroid used in the prevention of osteoporosis, and dehydroepiandrosterone (DHEA), a ubiquitous steroid precusor, are reported to be sulfated efficiently by SULT2A1 in vitro, yet unlike DHEA, raloxifene is not sulfated in vivo. This selectivity was explored in initial rate and equilibrium binding studies that demonstrate pronounced binding antisynergy (21-fold) between PAPS and raloxifene, but not DHEA. Analysis of crystal structures suggests that PAP binding restricts access to the acceptor-binding pocket by restructuring a nine-residue segment of the pocket edge that constricts the active site opening, or "pore", that sieves substrates on the basis of their geometries. In silico docking predicts that raloxifene, which is considerably larger than DHEA, can bind only to the unliganded (open) enzyme, whereas DHEA binds both the open and closed forms. The predictions of these structures with regard to substrate binding are tested using equilibrium and pre-steady-state ligand binding studies, and the results confirm that a nucleotide-driven isomerization controls access to the acceptor-binding pocket and plays an important role in substrate selection by SULT2A1 and possibly other sulfotransferases.

Original languageEnglish (US)
Pages (from-to)5674-5683
Number of pages10
JournalBiochemistry
Volume51
Issue number28
DOIs
StatePublished - Jul 17 2012

Fingerprint

Sulfotransferases
Dehydroepiandrosterone
Nucleotides
Phosphoadenosine Phosphosulfate
Substrates
Steroids
Sieves
Xenobiotics
Enzymes
Metabolites
Isomerization
Complex Mixtures
Access control
Liver
Computer Simulation
Sulfates
Osteoporosis
Catalytic Domain
Crystal structure
Ligands

ASJC Scopus subject areas

  • Biochemistry

Cite this

A nucleotide-gated molecular pore selects sulfotransferase substrates. / Cook, Ian T.; Wang, Ting; Falany, Charles N.; Leyh, Thomas S.

In: Biochemistry, Vol. 51, No. 28, 17.07.2012, p. 5674-5683.

Research output: Contribution to journalArticle

Cook, Ian T. ; Wang, Ting ; Falany, Charles N. ; Leyh, Thomas S. / A nucleotide-gated molecular pore selects sulfotransferase substrates. In: Biochemistry. 2012 ; Vol. 51, No. 28. pp. 5674-5683.
@article{3e8578f22b344fab9d3fa658035bd87d,
title = "A nucleotide-gated molecular pore selects sulfotransferase substrates",
abstract = "Human SULT2A1 is one of two predominant sulfotransferases in liver and catalyzes transfer of the sulfuryl moiety (-SO3) from activated sulfate (PAPS, 3′-phosphoadenosine 5-phosphosulfate) to hundreds of acceptors (metabolites and xenobiotics). Sulfation recodes the biologic activity of acceptors by altering their receptor interactions. The molecular basis on which these enzymes select and sulfonate specific acceptors from complex mixtures of competitors in vivo is a long-standing issue in the SULT field. Raloxifene, a synthetic steroid used in the prevention of osteoporosis, and dehydroepiandrosterone (DHEA), a ubiquitous steroid precusor, are reported to be sulfated efficiently by SULT2A1 in vitro, yet unlike DHEA, raloxifene is not sulfated in vivo. This selectivity was explored in initial rate and equilibrium binding studies that demonstrate pronounced binding antisynergy (21-fold) between PAPS and raloxifene, but not DHEA. Analysis of crystal structures suggests that PAP binding restricts access to the acceptor-binding pocket by restructuring a nine-residue segment of the pocket edge that constricts the active site opening, or {"}pore{"}, that sieves substrates on the basis of their geometries. In silico docking predicts that raloxifene, which is considerably larger than DHEA, can bind only to the unliganded (open) enzyme, whereas DHEA binds both the open and closed forms. The predictions of these structures with regard to substrate binding are tested using equilibrium and pre-steady-state ligand binding studies, and the results confirm that a nucleotide-driven isomerization controls access to the acceptor-binding pocket and plays an important role in substrate selection by SULT2A1 and possibly other sulfotransferases.",
author = "Cook, {Ian T.} and Ting Wang and Falany, {Charles N.} and Leyh, {Thomas S.}",
year = "2012",
month = "7",
day = "17",
doi = "10.1021/bi300631g",
language = "English (US)",
volume = "51",
pages = "5674--5683",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "28",

}

TY - JOUR

T1 - A nucleotide-gated molecular pore selects sulfotransferase substrates

AU - Cook, Ian T.

AU - Wang, Ting

AU - Falany, Charles N.

AU - Leyh, Thomas S.

PY - 2012/7/17

Y1 - 2012/7/17

N2 - Human SULT2A1 is one of two predominant sulfotransferases in liver and catalyzes transfer of the sulfuryl moiety (-SO3) from activated sulfate (PAPS, 3′-phosphoadenosine 5-phosphosulfate) to hundreds of acceptors (metabolites and xenobiotics). Sulfation recodes the biologic activity of acceptors by altering their receptor interactions. The molecular basis on which these enzymes select and sulfonate specific acceptors from complex mixtures of competitors in vivo is a long-standing issue in the SULT field. Raloxifene, a synthetic steroid used in the prevention of osteoporosis, and dehydroepiandrosterone (DHEA), a ubiquitous steroid precusor, are reported to be sulfated efficiently by SULT2A1 in vitro, yet unlike DHEA, raloxifene is not sulfated in vivo. This selectivity was explored in initial rate and equilibrium binding studies that demonstrate pronounced binding antisynergy (21-fold) between PAPS and raloxifene, but not DHEA. Analysis of crystal structures suggests that PAP binding restricts access to the acceptor-binding pocket by restructuring a nine-residue segment of the pocket edge that constricts the active site opening, or "pore", that sieves substrates on the basis of their geometries. In silico docking predicts that raloxifene, which is considerably larger than DHEA, can bind only to the unliganded (open) enzyme, whereas DHEA binds both the open and closed forms. The predictions of these structures with regard to substrate binding are tested using equilibrium and pre-steady-state ligand binding studies, and the results confirm that a nucleotide-driven isomerization controls access to the acceptor-binding pocket and plays an important role in substrate selection by SULT2A1 and possibly other sulfotransferases.

AB - Human SULT2A1 is one of two predominant sulfotransferases in liver and catalyzes transfer of the sulfuryl moiety (-SO3) from activated sulfate (PAPS, 3′-phosphoadenosine 5-phosphosulfate) to hundreds of acceptors (metabolites and xenobiotics). Sulfation recodes the biologic activity of acceptors by altering their receptor interactions. The molecular basis on which these enzymes select and sulfonate specific acceptors from complex mixtures of competitors in vivo is a long-standing issue in the SULT field. Raloxifene, a synthetic steroid used in the prevention of osteoporosis, and dehydroepiandrosterone (DHEA), a ubiquitous steroid precusor, are reported to be sulfated efficiently by SULT2A1 in vitro, yet unlike DHEA, raloxifene is not sulfated in vivo. This selectivity was explored in initial rate and equilibrium binding studies that demonstrate pronounced binding antisynergy (21-fold) between PAPS and raloxifene, but not DHEA. Analysis of crystal structures suggests that PAP binding restricts access to the acceptor-binding pocket by restructuring a nine-residue segment of the pocket edge that constricts the active site opening, or "pore", that sieves substrates on the basis of their geometries. In silico docking predicts that raloxifene, which is considerably larger than DHEA, can bind only to the unliganded (open) enzyme, whereas DHEA binds both the open and closed forms. The predictions of these structures with regard to substrate binding are tested using equilibrium and pre-steady-state ligand binding studies, and the results confirm that a nucleotide-driven isomerization controls access to the acceptor-binding pocket and plays an important role in substrate selection by SULT2A1 and possibly other sulfotransferases.

UR - http://www.scopus.com/inward/record.url?scp=84863931141&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84863931141&partnerID=8YFLogxK

U2 - 10.1021/bi300631g

DO - 10.1021/bi300631g

M3 - Article

C2 - 22703301

AN - SCOPUS:84863931141

VL - 51

SP - 5674

EP - 5683

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 28

ER -