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Title: Nucleotide Dependence of Subunit Rearrangements in Short-Form Rubisco Activase from Spinach

Journal Article · · Biochemistry

Higher-plant Rubisco activase (Rca) plays a critical role in regulating the activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). In vitro, Rca is known to undergo dynamic assembly–disassembly processes, with several oligomer stoichiometries coexisting over a broad concentration range. Although the hexamer appears to be the active form, changes in quaternary structure could play a role in Rubisco regulation. Therefore, in this work, fluorescent labels were attached to the C-termini of spinach β-Rca, and the rate of subunit mixing was monitored by measuring energy transfer as a function of nucleotide and divalent cation. Only dimeric units appeared to exchange. Poorly hydrolyzable substrate analogues provided locked complexes with high thermal stabilities (apparent Tm = 60 °C) and an estimated t1/2 of at least 7 h, whereas ATP-Mg provided tight assemblies with t1/2 values of 30–40 min and ADP-Mg loose assemblies with t1/2 values of <15 min. Accumulation of ADP to 20% of the total level of adenine nucleotide substantially accelerated equilibration. An initial lag period was observed with ATP·Mg, indicating inhibition of subunit exchange at low ADP concentrations. The ADP Ki value was estimated to exceed the Km for ATP (0.772 ± 96 mM), suggesting that the equilibration rate is a function of the relative contributions of high- and low-affinity states. C-Terminal cross-linking generated covalent dimers, required the N-terminal extension to the AAA+ domain, and provided evidence of different classes of sites. We propose that oligomer reorganization may be stalled during periods of high Rubisco reactivation activity, whereas changes in quaternary structure are stimulated by the accumulation of ADP at low light levels.

Research Organization:
Arizona State Univ., Tempe, AZ (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0002423; FG02-09-ER16123
OSTI ID:
1534425
Journal Information:
Biochemistry, Vol. 56, Issue 36; ISSN 0006-2960
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 4 works
Citation information provided by
Web of Science

References (40)

Regulation of Rubisco activase and its interaction with Rubisco journal June 2007
Catalysis and regulation in Rubisco journal June 2007
The Regulatory Properties of Rubisco Activase Differ among Species and Affect Photosynthetic Induction during Light Transitions journal February 2013
Rubisco activity and regulation as targets for crop improvement journal November 2012
Degradation of potent Rubisco inhibitor by selective sugar phosphatase journal January 2015
Biogenesis and Metabolic Maintenance of Rubisco journal April 2017
Structural Characterization of a Newly Identified Component of α-Carboxysomes: The AAA+ Domain Protein CsoCbbQ journal November 2015
Identification and characterization of multiple rubisco activases in chemoautotrophic bacteria journal November 2015
High Temperature Effects on Electron and Proton Circuits of Photosynthesis journal July 2010
Rubisco and Rubisco Activase Play an Important Role in the Biochemical Limitations of Photosynthesis in Rice, Wheat, and Maize under High Temperature and Water Deficit journal April 2017
Mechanistic insights into bacterial AAA+ proteases and protein-remodelling machines journal December 2015
The ClpXP Protease Unfolds Substrates Using a Constant Rate of Pulling but Different Gears journal October 2013
Stochastic but Highly Coordinated Protein Unfolding and Translocation by the ClpXP Proteolytic Machine journal July 2014
Substrate-translocating loops regulate mechanochemical coupling and power production in AAA+ protease ClpXP journal September 2016
Structure of green-type Rubisco activase from tobacco journal November 2011
Protein Oligomerization Monitored by Fluorescence Fluctuation Spectroscopy: Self-Assembly of Rubisco Activase journal September 2012
ATP and Magnesium Promote Cotton Short-Form Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (Rubisco) Activase Hexamer Formation at Low Micromolar Concentrations journal November 2014
The Two Forms of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Activase Differ in Sensitivity to Elevated Temperature journal June 1997
Structural changes associated with the acute thermal instability of Rubisco activase journal July 2010
Biophysical characterization of higher plant Rubisco activase journal January 2013
An efficient system for high-level expression and easy purification of authentic recombinant proteins journal May 2004
Measurement of protein using bicinchoninic acid journal October 1985
Purification and Characterization of the AAA+ Domain of Sinorhizobium meliloti DctD, a σ 54 -Dependent Transcriptional Activator journal June 2004
Accurate FRET Measurements within Single Diffusing Biomolecules Using Alternating-Laser Excitation journal April 2005
A continuous spectrophotometric assay for inorganic phosphate and for measuring phosphate release kinetics in biological systems. journal June 1992
Subunit interactions of Rubisco activase: Polyethylene glycol promotes self-association, stimulates ATPase and activation activities, and enhances interactions with Rubisco journal November 1992
Photosynthesis-deficient Mutants of Chlamydomonas reinhardii with Associated Light-sensitive Phenotypes journal March 1981
First Crystal Structure of Rubisco from a Green Alga,Chlamydomonas reinhardtii journal December 2001
Thermofluor-based high-throughput stability optimization of proteins for structural studies journal October 2006
Potential for interactions between the carboxy- and amino-termini of Rubisco activase subunits journal February 2004
A non-radioactive method for measuring Rubisco activase activity in the presence of variable ATP: ADP ratios, including modifications for measuring the activity and activation state of Rubisco journal January 2014
Asymmetric Interactions of ATP with the AAA+ ClpX6 Unfoldase: Allosteric Control of a Protein Machine journal July 2005
Nucleotide Binding and Conformational Switching in the Hexameric Ring of a AAA+ Machine journal April 2013
Atomic Resolution X-ray Structure of the Substrate Recognition Domain of Higher Plant Ribulose-bisphosphate Carboxylase/Oxygenase (Rubisco) Activase journal August 2011
Identification of critical arginine residues in the functioning of Rubisco activase journal June 2006
Evolutionary Relationships and Structural Mechanisms of aaa+ Proteins journal June 2006
Metabolome analysis of photosynthesis and the related primary metabolites in the leaves of transgenic rice plants with increased or decreased Rubisco content: Metabolome analysis of Rubisco transgenic rice journal March 2012
Mechanism of light regulation of Rubisco: A specific role for the larger Rubisco activase isoform involving reductive activation by thioredoxin-f journal August 1999
Activation of interspecies-hybrid Rubisco enzymes to assess different models for the Rubisco–Rubisco activase interaction journal April 2013
Structures of Asymmetric ClpX Hexamers Reveal Nucleotide-Dependent Motions in a AAA+ Protein-Unfolding Machine journal November 2009

Cited By (3)

Single-molecule diffusometry reveals the nucleotide-dependent oligomerization pathways of Nicotiana tabacum Rubisco activase journal March 2018
Cyanobacterial carboxysomes contain an unique rubisco‐activase‐like protein journal October 2019
Probing the rice Rubisco–Rubisco activase interaction via subunit heterooligomerization journal November 2019

Figures / Tables (10)