Control of ATP Hydrolysis by ADP Bound at the Catalytic Site of Chloroplast ATP Synthase As Related to Protonmotive Force and Mg2+

Ziyun Du, Paul D. Boyer

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. Our data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg2+ with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg2+ is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg2+ released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg2+ the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg2+ and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg2+. The replacement of [3H]ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg2+ and ADP bound at one catalytic site without Pi block catalysis by all three enzyme sites. The inhibited form induced by Mg2+ and ADP may occur only under laboratory conditions and not have an in vivo role.

Original languageEnglish (US)
Pages (from-to)873-879
Number of pages7
JournalBiochemistry
Volume28
Issue number2
DOIs
StatePublished - Jan 1 1989

Fingerprint

Chloroplast Proton-Translocating ATPases
Adenosine Diphosphate
Hydrolysis
Catalytic Domain
Adenosine Triphosphate
Adenosine Triphosphatases
Chemical activation
Ca(2+) Mg(2+)-ATPase
Chloroplasts
Membranes
Photophosphorylation
Light
Chelation
Catalysis
Washing
Edetic Acid
Dilution

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Control of ATP Hydrolysis by ADP Bound at the Catalytic Site of Chloroplast ATP Synthase As Related to Protonmotive Force and Mg2+. / Du, Ziyun; Boyer, Paul D.

In: Biochemistry, Vol. 28, No. 2, 01.01.1989, p. 873-879.

Research output: Contribution to journalArticle

@article{5c0f5c0abc7543579fbb199cd76b1aed,
title = "Control of ATP Hydrolysis by ADP Bound at the Catalytic Site of Chloroplast ATP Synthase As Related to Protonmotive Force and Mg2+",
abstract = "The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. Our data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg2+ with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg2+ is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg2+ released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg2+ the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg2+ and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg2+. The replacement of [3H]ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg2+ and ADP bound at one catalytic site without Pi block catalysis by all three enzyme sites. The inhibited form induced by Mg2+ and ADP may occur only under laboratory conditions and not have an in vivo role.",
author = "Ziyun Du and Boyer, {Paul D.}",
year = "1989",
month = "1",
day = "1",
doi = "10.1021/bi00428a070",
language = "English (US)",
volume = "28",
pages = "873--879",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "2",

}

TY - JOUR

T1 - Control of ATP Hydrolysis by ADP Bound at the Catalytic Site of Chloroplast ATP Synthase As Related to Protonmotive Force and Mg2+

AU - Du, Ziyun

AU - Boyer, Paul D.

PY - 1989/1/1

Y1 - 1989/1/1

N2 - The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. Our data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg2+ with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg2+ is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg2+ released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg2+ the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg2+ and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg2+. The replacement of [3H]ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg2+ and ADP bound at one catalytic site without Pi block catalysis by all three enzyme sites. The inhibited form induced by Mg2+ and ADP may occur only under laboratory conditions and not have an in vivo role.

AB - The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. Our data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg2+ with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg2+ is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg2+ released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg2+ the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg2+ and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg2+. The replacement of [3H]ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg2+ and ADP bound at one catalytic site without Pi block catalysis by all three enzyme sites. The inhibited form induced by Mg2+ and ADP may occur only under laboratory conditions and not have an in vivo role.

UR - http://www.scopus.com/inward/record.url?scp=0000153697&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000153697&partnerID=8YFLogxK

U2 - 10.1021/bi00428a070

DO - 10.1021/bi00428a070

M3 - Article

VL - 28

SP - 873

EP - 879

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 2

ER -