Effects of rare earth ions on activity of RuBPcase in tobacco

• Published in: Plant science (Limerick) Vol. 152; no. 2; pp. 145 - 151
• Main Authors: Chen, W.-J, Gu, Y.-H, Zhao, G.-W, Tao, Y, Luo, J.-P, Hu, T.-D
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 21.03.2000; Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; application rate; Biological and medical sciences; cerium; container-grown plants; Economic plant physiology; enzyme activity; Enzymes; Fundamental and applied biological sciences. Psychology; gadolinium; hydroponics; ions; lanthanum; magnesium; Metabolism; Nicotiana tabacum; Nutrition. Photosynthesis. Respiration. Metabolism; phytotoxicity; plant physiology; Plant physiology and development; rare earth elements; Rare earth ions; ribulose-bisphosphate carboxylase; RuBPcase; Tobacco; Rare earth ions; Tobacco; RuBPcase; Enzyme; Cerium; Ribulose-bisphosphate carboxylase; Stimulant plant; Gadolinium; Molecular interaction; Lyases; Nicotiana tabacum; Dose activity relation; Trace element; Carbon-carbon lyases; Regulation(control); Lanthanide ion; Enzymatic activity; Carboxy-lyases; Dicotyledones; Angiospermae; Spermatophyta; Solanaceae; Lanthanum
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/S0168-9452(99)00235-6

To investigate the physiological effects of rare earth ions, we have studied the effect of LaCl 3 on the activity of ribulose 1,5-bisphosphate carboxylase (RuBPcase) in tobacco ( Nicotiana tobacum). When treated with 20–80 μmol/l LaCl 3 in Hoagland solution by water culture or by spraying with 400–1600 μmol/l LaCl 3 in pot experiment, the total and initial activities of RuBPcase were raised gradually, but decreased when the concentrations of LaCl 3 were ≥200 μmol/l in water culture and >1600 μmol/l by spraying. It was indicated that LaCl 3 promoted the activation of RuBPcase at low concentrations in vivo. It was also proved that lanthanides (Ln 3+) increased the activity of RuBPcase in vitro. Upon addition of different concentrations of Ln 3+ to replace Mg 2+, the RuBPcase activity exhibited an apparently biphasic response curve. Among the three Ln 3+ tested, the activation effects of La 3+ and Ce 3+ on RuBPcase were greater than that of Gd 3+, but the activation effects of all the three Ln 3+ were lower at high concentrations than that of Mg 2+, showing strongly inhibitory function. The extended X-ray absorption fine structure study of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco)–La complex indicated that La is bound with the oxygen atoms of amino acid residues, with the distance of the LaO bond being 2.51 Å. The mechanism of molecular interaction between Ln 3+ and RuBPcase is discussed.