Abstract
The ATPase activity and fluoresence of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activase were determined over a range of MgCl2, KCl, and activase concentrations. Both salts promoted ADP release from ATP and intrinsic fluorescence enhancement by adenosine 5[prime]-[[gamma]-thio] triphosphate, but Mg2+ was about 10 times more effective than K+. ATPase and fluorescence enhancement both increased from zero to saturation within the same Mg2+ and K+ concentration ranges. At saturating concentrations (5 mM Mg2+ and 22 mM K+), 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.
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- Bork P., Sander C., Valencia A. An ATPase domain common to prokaryotic cell cycle proteins, sugar kinases, actin, and hsp70 heat shock proteins. Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7290–7294. doi: 10.1073/pnas.89.16.7290. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brooks A., Portis A. R. Protein-bound ribulose bisphosphate correlates with deactivation of ribulose bisphosphate carboxylase in leaves. Plant Physiol. 1988 May;87(1):244–249. doi: 10.1104/pp.87.1.244. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carlier M. F., Pantaloni D., Korn E. D. The effects of Mg2+ at the high-affinity and low-affinity sites on the polymerization of actin and associated ATP hydrolysis. J Biol Chem. 1986 Aug 15;261(23):10785–10792. [PubMed] [Google Scholar]
- Lan Y., Mott K. A. Determination of Apparent K(m) Values for Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco) Activase Using the Spectrophotometric Assay of Rubisco Activity. Plant Physiol. 1991 Feb;95(2):604–609. doi: 10.1104/pp.95.2.604. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Li L. A., Tabita F. R. Transcription control of ribulose bisphosphate carboxylase/oxygenase activase and adjacent genes in Anabaena species. J Bacteriol. 1994 Nov;176(21):6697–6706. doi: 10.1128/jb.176.21.6697-6706.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Maruyama K., Tsukagoshi K. Effects of KCl, MgCl2, and CaCl2 concentrations on the monomer-polymer equilibrium of actin in the presence and absence of cytochalasin D. J Biochem. 1984 Sep;96(3):605–611. doi: 10.1093/oxfordjournals.jbchem.a134875. [DOI] [PubMed] [Google Scholar]
- Pollard T. D., Cooper J. A. Actin and actin-binding proteins. A critical evaluation of mechanisms and functions. Annu Rev Biochem. 1986;55:987–1035. doi: 10.1146/annurev.bi.55.070186.005011. [DOI] [PubMed] [Google Scholar]
- Robinson S. P., Portis A. R., Jr Adenosine triphosphate hydrolysis by purified rubisco activase. Arch Biochem Biophys. 1989 Jan;268(1):93–99. doi: 10.1016/0003-9861(89)90568-7. [DOI] [PubMed] [Google Scholar]
- Robinson S. P., Streusand V. J., Chatfield J. M., Portis A. R. Purification and assay of rubisco activase from leaves. Plant Physiol. 1988 Dec;88(4):1008–1014. doi: 10.1104/pp.88.4.1008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Salvucci M. E. Subunit interactions of Rubisco activase: polyethylene glycol promotes self-association, stimulates ATPase and activation activities, and enhances interactions with Rubisco. Arch Biochem Biophys. 1992 Nov 1;298(2):688–696. doi: 10.1016/0003-9861(92)90467-b. [DOI] [PubMed] [Google Scholar]
- Salvucci M. E., Werneke J. M., Ogren W. L., Portis A. R. Purification and species distribution of rubisco activase. Plant Physiol. 1987 Jul;84(3):930–936. doi: 10.1104/pp.84.3.930. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shen J. B., Orozco E. M., Jr, Ogren W. L. Expression of the two isoforms of spinach ribulose 1,5-bisphosphate carboxylase activase and essentiality of the conserved lysine in the consensus nucleotide-binding domain. J Biol Chem. 1991 May 15;266(14):8963–8968. [PubMed] [Google Scholar]
- Stitt M., Lilley R. M., Heldt H. W. Adenine nucleotide levels in the cytosol, chloroplasts, and mitochondria of wheat leaf protoplasts. Plant Physiol. 1982 Oct;70(4):971–977. doi: 10.1104/pp.70.4.971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stossel T. P., Chaponnier C., Ezzell R. M., Hartwig J. H., Janmey P. A., Kwiatkowski D. J., Lind S. E., Smith D. B., Southwick F. S., Yin H. L. Nonmuscle actin-binding proteins. Annu Rev Cell Biol. 1985;1:353–402. doi: 10.1146/annurev.cb.01.110185.002033. [DOI] [PubMed] [Google Scholar]
- Sánchez de Jiménez E., Medrano L., Martínez-Barajas E. Rubisco activase, a possible new member of the molecular chaperone family. Biochemistry. 1995 Mar 7;34(9):2826–2831. doi: 10.1021/bi00009a012. [DOI] [PubMed] [Google Scholar]
- Wang Z. Y., Ramage R. T., Portis A. R., Jr Mg2+ and ATP or adenosine 5'-[gamma-thio]-triphosphate (ATP gamma S) enhances intrinsic fluorescence and induces aggregation which increases the activity of spinach Rubisco activase. Biochim Biophys Acta. 1993 Sep 3;1202(1):47–55. doi: 10.1016/0167-4838(93)90061-u. [DOI] [PubMed] [Google Scholar]
- Wang Z. Y., Snyder G. W., Esau B. D., Portis A. R., Ogren W. L. Species-dependent variation in the interaction of substrate-bound ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) and rubisco activase. Plant Physiol. 1992 Dec;100(4):1858–1862. doi: 10.1104/pp.100.4.1858. [DOI] [PMC free article] [PubMed] [Google Scholar]