Effects of rare earth ions on activity of RuBPcase in tobacco
Effects of rare earth ions on activity of RuBPcase in tobacco
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DOI：
10.1016/s0168-9452(99)00235-6
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发表时间：
2000-03-21
期刊：
影响因子：
5.2
通讯作者：
Hu, TD
中科院分区：
文献类型：
--
作者：
Chen, WJ;Gu, YH;Hu, TD
为探讨稀土离子的生理效应，研究了LaCl 3对烟草（Nicotiana tobacum）核酮糖1，5-二磷酸羧化酶（RuBPcase）活性的影响。在盆栽试验中，用20-80 μ mol/lLaCl_3的Hoagland溶液水培或用400-1600 μ mol/lLaC_（1）_3喷雾处理，RuBP_（case）的总活性和初始活性逐渐升高，但当LaCl_3浓度大于或等于200 μ mol/l（水培）和> 1600 μ mol/l（喷雾）时，RuBP_（case）的总活性和初始活性下降。结果表明，低浓度的LaCl_3在体内可促进RuBP酶的活化。在体外实验中，镧系元素（Ln（3+））对RuBP酶活性有明显的增强作用。加入不同浓度的Ln（3+）替代Mg（2+）后，RuBPcase活性呈现明显的双相反应曲线。在3种稀土离子中，La 3+和Ce 3+对RuBPcase的激活作用大于Gd 3+，但3种稀土离子在高浓度时的激活作用均低于Mg 2+，表现出较强的抑制作用。对核酮糖1，5-二磷酸羧化酶/加氧酶（Rubisco）-La复合物的扩展X射线吸收精细结构研究表明，La与氨基酸残基上的氧原子结合，La-O键的距离为2.51埃。讨论了Ln（3+）与RuBPcase的分子相互作用机理。(C)2000由Elsevier Science爱尔兰有限公司出版。保留所有权利。
To investigate the physiological effects of rare earth ions, we have studied the effect of LaCl3 on the activity of ribulose 1,5-bisphosphate carboxylase (RuBPcase) in tobacco (Nicotiana tobacum). When treated with 20-80 mu mol/l LaCl3 in Hoagland solution by water culture or by spraying with 400-1600 mu mol/l LaC(l)3 in pot experiment, the total and initial activities of RuBPcase were raised gradually, but decreased when the concentrations of LaCl3 were greater than or equal to 200 mu mol/l in water culture and > 1600 mu mol/l by spraying. it was indicated that LaCl3 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 Mg2+, the RuBPcase activity exhibited an apparently biphasic response curve. Among the three Ln(3+) tested, the activation effects of La3+ and Ce3+ on RuBPcase were greater than that of Gd3+, but the activation effects of all the three Ln(3+) were lower at high concentrations than that of Mg2+, 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 Angstrom. The mechanism of molecular interaction between Ln(3+) and RuBPcase is discussed. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.