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Title: ATP hydrolysis activity and polymerization state of ribulose-1,5-bisphosphate carboxylase oxygenase activase: Do the effects of Mg{sup 2+}, K{sup +}, and activase concentrations indicate a functional similarity to actin?

Abstract

The ATPase activity and fluorescence of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activase were determined over a range of MgCl{sub 2}, KCl, and activase concentrations. Both salts promoted ADP release from ATP and intrinsic fluorescence enhancement by adenosine 5{prime}-[{gamma}-thio] triphosphate, but Mg{sup 2+} was about 10 times more effective than K{sup +}. ATPase and fluorescence enhancement both increased from zero to saturation within the same Mg{sup 2+} and K{sup +} concentration ranges. At saturating concentrations (5 mm Mg{sup 2+} and 22 mm K{sup +}), the specific activity of ATPase (turnover time, about 1 s) and specific intrinsic fluorescence enhancement were maximal and unaffected by activase concentration above 1 {mu}m activase; below 1 {mu}m activase, both decreased sharply. These responses are remarkably similar to the behavior of actin. Intrinsic fluorescence enhancement of Rubisco activase reflects the extent of polymerization, showing that the smaller oligomer or monomer present in low-salt and activase concentrations is inactive in ATP hydrolysis. However, quenching of 1-anilinonapthaline-8-sulfonate fluorescence revealed that ADP and adenosine 5{prime}-[{gamma}-thio] triphosphate bind equally well to activase at low- and high-salt concentrations. This is consistent with an actin-like mechanism requiring a dynamic equilibrium between monomer and oligomers for ATP hydrolysis. The specific activation rate of substrate-boundmore » decarbamylated Rubisco decreased at activase concentrations below 1 {mu}m. This suggests that a large oligomeric form of activase, rather than a monomer, interacts with Rubisco when performing the release of bound ribulose-1,5-bisphosphate from the inactive enzyme.« less

Authors:
 [1];  [2]
  1. Univ. of Wollongong (Australia)
  2. Univ. of Illinois, Urbana, IL (United States)
Publication Date:
OSTI Identifier:
576828
DOE Contract Number:  
AI02-94ER20154
Resource Type:
Journal Article
Journal Name:
Plant Physiology (Bethesda)
Additional Journal Information:
Journal Volume: 114; Journal Issue: 2; Other Information: PBD: Jun 1997
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; CARBOXYLASE; RIBULOSE; ATP-ASE; BIOCHEMISTRY; PLANTS; HYDROLYSIS; OXYGENASES

Citation Formats

Lilley, R M, and Portis, Jr, A R. ATP hydrolysis activity and polymerization state of ribulose-1,5-bisphosphate carboxylase oxygenase activase: Do the effects of Mg{sup 2+}, K{sup +}, and activase concentrations indicate a functional similarity to actin?. United States: N. p., 1997. Web.
Lilley, R M, & Portis, Jr, A R. ATP hydrolysis activity and polymerization state of ribulose-1,5-bisphosphate carboxylase oxygenase activase: Do the effects of Mg{sup 2+}, K{sup +}, and activase concentrations indicate a functional similarity to actin?. United States.
Lilley, R M, and Portis, Jr, A R. Sun . "ATP hydrolysis activity and polymerization state of ribulose-1,5-bisphosphate carboxylase oxygenase activase: Do the effects of Mg{sup 2+}, K{sup +}, and activase concentrations indicate a functional similarity to actin?". United States.
@article{osti_576828,
title = {ATP hydrolysis activity and polymerization state of ribulose-1,5-bisphosphate carboxylase oxygenase activase: Do the effects of Mg{sup 2+}, K{sup +}, and activase concentrations indicate a functional similarity to actin?},
author = {Lilley, R M and Portis, Jr, A R},
abstractNote = {The ATPase activity and fluorescence of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activase were determined over a range of MgCl{sub 2}, KCl, and activase concentrations. Both salts promoted ADP release from ATP and intrinsic fluorescence enhancement by adenosine 5{prime}-[{gamma}-thio] triphosphate, but Mg{sup 2+} was about 10 times more effective than K{sup +}. ATPase and fluorescence enhancement both increased from zero to saturation within the same Mg{sup 2+} and K{sup +} concentration ranges. At saturating concentrations (5 mm Mg{sup 2+} and 22 mm K{sup +}), the specific activity of ATPase (turnover time, about 1 s) and specific intrinsic fluorescence enhancement were maximal and unaffected by activase concentration above 1 {mu}m activase; below 1 {mu}m activase, both decreased sharply. These responses are remarkably similar to the behavior of actin. Intrinsic fluorescence enhancement of Rubisco activase reflects the extent of polymerization, showing that the smaller oligomer or monomer present in low-salt and activase concentrations is inactive in ATP hydrolysis. However, quenching of 1-anilinonapthaline-8-sulfonate fluorescence revealed that ADP and adenosine 5{prime}-[{gamma}-thio] triphosphate bind equally well to activase at low- and high-salt concentrations. This is consistent with an actin-like mechanism requiring a dynamic equilibrium between monomer and oligomers for ATP hydrolysis. The specific activation rate of substrate-bound decarbamylated Rubisco decreased at activase concentrations below 1 {mu}m. This suggests that a large oligomeric form of activase, rather than a monomer, interacts with Rubisco when performing the release of bound ribulose-1,5-bisphosphate from the inactive enzyme.},
doi = {},
url = {https://www.osti.gov/biblio/576828}, journal = {Plant Physiology (Bethesda)},
number = 2,
volume = 114,
place = {United States},
year = {1997},
month = {6}
}