Anatomy of an energy-coupling mechanism - The interlocking catalytic cycles of the ATP sulfurylase-GTPase system

Meihao Sun, Thomas S. Leyh

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

ATP sulfurylase, from Escherichia coli K-12, conformationally couples the rates and chemical potentials of the two reactions that it catalyzes, GTP hydrolysis and activated sulfate synthesis. The enzyme is rare among such coupling systems in that it links the potentials of small-molecule chemistries to one another, rather than to vectorial motion. The pre-steady-state stages of the catalytic cycle of ATP sulfurylase were studied using tools capable of distinguishing between enzyme-bound and solution-phase product for each of the four products of the enzyme. The study reveals that the two chemistries are linked at multiple points in the reaction coordinate. Linking begins with an isomerization prior to chemistry that initiates an ordered cleavage of the β,γ and α,β bonds of GTP and ATP, respectively; the rates of these three sequential events increase successively, causing them to appear simultaneous. Linking is again seen in the late stages of the catalytic cycle: product release is ordered with Pi departing prior to either GDP or PPi. Release rate constants are determined for each product and used to construct a quantitative model of the mechanism that accurately predicts the behavior of this complex system.

Original languageEnglish (US)
Pages (from-to)13941-13948
Number of pages8
JournalBiochemistry
Volume44
Issue number42
DOIs
StatePublished - Oct 25 2005

Fingerprint

Sulfate Adenylyltransferase
GTP Phosphohydrolases
Anatomy
Guanosine Triphosphate
Enzymes
Chemical potential
Isomerization
Escherichia coli
Sulfates
Large scale systems
Hydrolysis
Rate constants
Adenosine Triphosphate
Molecules

ASJC Scopus subject areas

  • Biochemistry

Cite this

Anatomy of an energy-coupling mechanism - The interlocking catalytic cycles of the ATP sulfurylase-GTPase system. / Sun, Meihao; Leyh, Thomas S.

In: Biochemistry, Vol. 44, No. 42, 25.10.2005, p. 13941-13948.

Research output: Contribution to journalArticle

@article{6d11a569171e4e5c89637cee41ef1d1a,
title = "Anatomy of an energy-coupling mechanism - The interlocking catalytic cycles of the ATP sulfurylase-GTPase system",
abstract = "ATP sulfurylase, from Escherichia coli K-12, conformationally couples the rates and chemical potentials of the two reactions that it catalyzes, GTP hydrolysis and activated sulfate synthesis. The enzyme is rare among such coupling systems in that it links the potentials of small-molecule chemistries to one another, rather than to vectorial motion. The pre-steady-state stages of the catalytic cycle of ATP sulfurylase were studied using tools capable of distinguishing between enzyme-bound and solution-phase product for each of the four products of the enzyme. The study reveals that the two chemistries are linked at multiple points in the reaction coordinate. Linking begins with an isomerization prior to chemistry that initiates an ordered cleavage of the β,γ and α,β bonds of GTP and ATP, respectively; the rates of these three sequential events increase successively, causing them to appear simultaneous. Linking is again seen in the late stages of the catalytic cycle: product release is ordered with Pi departing prior to either GDP or PPi. Release rate constants are determined for each product and used to construct a quantitative model of the mechanism that accurately predicts the behavior of this complex system.",
author = "Meihao Sun and Leyh, {Thomas S.}",
year = "2005",
month = "10",
day = "25",
doi = "10.1021/bi051303e",
language = "English (US)",
volume = "44",
pages = "13941--13948",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "42",

}

TY - JOUR

T1 - Anatomy of an energy-coupling mechanism - The interlocking catalytic cycles of the ATP sulfurylase-GTPase system

AU - Sun, Meihao

AU - Leyh, Thomas S.

PY - 2005/10/25

Y1 - 2005/10/25

N2 - ATP sulfurylase, from Escherichia coli K-12, conformationally couples the rates and chemical potentials of the two reactions that it catalyzes, GTP hydrolysis and activated sulfate synthesis. The enzyme is rare among such coupling systems in that it links the potentials of small-molecule chemistries to one another, rather than to vectorial motion. The pre-steady-state stages of the catalytic cycle of ATP sulfurylase were studied using tools capable of distinguishing between enzyme-bound and solution-phase product for each of the four products of the enzyme. The study reveals that the two chemistries are linked at multiple points in the reaction coordinate. Linking begins with an isomerization prior to chemistry that initiates an ordered cleavage of the β,γ and α,β bonds of GTP and ATP, respectively; the rates of these three sequential events increase successively, causing them to appear simultaneous. Linking is again seen in the late stages of the catalytic cycle: product release is ordered with Pi departing prior to either GDP or PPi. Release rate constants are determined for each product and used to construct a quantitative model of the mechanism that accurately predicts the behavior of this complex system.

AB - ATP sulfurylase, from Escherichia coli K-12, conformationally couples the rates and chemical potentials of the two reactions that it catalyzes, GTP hydrolysis and activated sulfate synthesis. The enzyme is rare among such coupling systems in that it links the potentials of small-molecule chemistries to one another, rather than to vectorial motion. The pre-steady-state stages of the catalytic cycle of ATP sulfurylase were studied using tools capable of distinguishing between enzyme-bound and solution-phase product for each of the four products of the enzyme. The study reveals that the two chemistries are linked at multiple points in the reaction coordinate. Linking begins with an isomerization prior to chemistry that initiates an ordered cleavage of the β,γ and α,β bonds of GTP and ATP, respectively; the rates of these three sequential events increase successively, causing them to appear simultaneous. Linking is again seen in the late stages of the catalytic cycle: product release is ordered with Pi departing prior to either GDP or PPi. Release rate constants are determined for each product and used to construct a quantitative model of the mechanism that accurately predicts the behavior of this complex system.

UR - http://www.scopus.com/inward/record.url?scp=27144499491&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27144499491&partnerID=8YFLogxK

U2 - 10.1021/bi051303e

DO - 10.1021/bi051303e

M3 - Article

C2 - 16229483

AN - SCOPUS:27144499491

VL - 44

SP - 13941

EP - 13948

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 42

ER -