Abstract
The diurnal change in activity of ribulose 1,5-bisphosphate (Rbu-1,5-P2) carboxylase [3-phospho-D-glycerate carboxy-lyase (dimerizing); EC 4.1.1.39] of leaves of Phaseolus vulgaris is regulated (in part) by mechanisms that control the level of an endogenous inhibitor that binds tightly to the activated (carbamoylated) form of Rbu-1,5-P2 carboxylase. This inhibitor was extracted from leaves and copurified with the Rbu-1,5-P2 carboxylase of the leaves. Further purification by ion-exchange chromatography, adsorption to purified Rbu-1,5-P2 carboxylase, barium precipitation, and HPLC separation yielded a phosphorylated compound that was a strong inhibitor of Rbu-1,5-P2 carboxylase. The compound was analyzed by GC/MS, 13C NMR, and 1H NMR and shown to be 2-carboxyarabinitol 1-phosphate [(2-C-phosphohydroxymethyl)-D-ribonic acid]. Verification of structure was obtained by comparison of the inhibitory activity of the isolated compound with that of 2-carboxy-D-arabinitol 1-phosphate synthesized in vitro. This compound (but not 2-carboxy-D-arabinitol 5-phosphate) inhibited Rbu-1,5-P2 carboxylase in a way that was kinetically identical to that of the isolated, naturally occurring compound. The structure of the isolated compound differs from the Rbu-1,5-P2 carboxylase transition-state analogue 2-carboxyarabinitol 1,5-bisphosphate only by the lack of the C-5 phosphate group. This difference results in a higher binding constant for the monophosphate (Kd = 32 nM) compared with the bisphosphate (Kd < 10 pM). The less tightly bound compound acts in a light-dependent, reversible regulation of Rbu-1,5-P2 carboxylase activity in vivo.
Keywords: photosynthesis, CO2 fixation, enzyme regulation, enzyme inhibitor, phosphate ester
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Lapper R. D., Smith I. C. A 13 C and 1 H nuclear magnetic resonance study of the conformations of 2',3'-cyclic nucleotides. J Am Chem Soc. 1973 May 2;95(9):2878–2880. doi: 10.1021/ja00790a024. [DOI] [PubMed] [Google Scholar]
- Pierce J., Tolbert N. E., Barker R. Interaction of ribulosebisphosphate carboxylase/oxygenase with transition-state analogues. Biochemistry. 1980 Mar 4;19(5):934–942. doi: 10.1021/bi00546a018. [DOI] [PubMed] [Google Scholar]
- Schloss J. V., Lorimer G. H. The stereochemical course of ribulosebisphosphate carboxylase. Reductive trapping of the 6-carbon reaction-intermediate. J Biol Chem. 1982 May 10;257(9):4691–4694. [PubMed] [Google Scholar]
- Seemann J. R., Badger M. R., Berry J. A. Variations in the Specific Activity of Ribulose-1,5-bisphosphate Carboxylase between Species Utilizing Differing Photosynthetic Pathways. Plant Physiol. 1984 Apr;74(4):791–794. doi: 10.1104/pp.74.4.791. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Seemann J. R., Berry J. A., Freas S. M., Krump M. A. Regulation of ribulose bisphosphate carboxylase activity in vivo by a light-modulated inhibitor of catalysis. Proc Natl Acad Sci U S A. 1985 Dec;82(23):8024–8028. doi: 10.1073/pnas.82.23.8024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Servaites J. C. Binding of a Phosphorylated Inhibitor to Ribulose Bisphosphate Carboxylase/Oxygenase during the Night. Plant Physiol. 1985 Aug;78(4):839–843. doi: 10.1104/pp.78.4.839. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sharkey T. D., Seemann J. R., Berry J. A. Regulation of Ribulose-1,5-Bisphosphate Carboxylase Activity in Response to Changing Partial Pressure of O(2) and Light in Phaseolus vulgaris. Plant Physiol. 1986 Jul;81(3):788–791. doi: 10.1104/pp.81.3.788. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vu C. V., Allen L. H., Bowes G. Effects of Light and Elevated Atmospheric CO(2) on the Ribulose Bisphosphate Carboxylase Activity and Ribulose Bisphosphate Level of Soybean Leaves. Plant Physiol. 1983 Nov;73(3):729–734. doi: 10.1104/pp.73.3.729. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vu J. C., Allen L. H., Bowes G. Dark/Light modulation of ribulose bisphosphate carboxylase activity in plants from different photosynthetic categories. Plant Physiol. 1984 Nov;76(3):843–845. doi: 10.1104/pp.76.3.843. [DOI] [PMC free article] [PubMed] [Google Scholar]
