The Regulatory Properties of Rubisco Activase Differ among Species and Affect Photosynthetic Induction during Light Transitions
The Regulatory Properties of Rubisco Activase Differ among Species and Affect Photosynthetic Induction during Light Transitions
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DOI：
10.1104/pp.112.213348
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发表时间：
2013-04-01
期刊：
影响因子：
7.4
通讯作者：
Salvucci, Michael E.
中科院分区：
文献类型：
--
作者：
Carmo-Silva, A. Elizabete;Salvucci, Michael E.
Rubisco的催化伴侣Rubisco活化酶（Rca）利用ATP水解产生的能量恢复Rubisco的催化活性。在拟南芥（Arabidopsis thaliana）中，ADP对Rca活性的抑制通过α-同种型的氧化还原调节来微调。为了阐明仅含有氧化还原不敏感的β-同种型的物种中Rca调节的机制，表征了不同Rca形式的活性对ADP的响应。当在叶提取物中测定时，在含有α-Rca和β-Rca（拟南芥和亚麻荠[亚麻荠]）或仅含有β-Rca（烟草[烟草]）的物种中，ADP与ATP的生理比率显著抑制Rubisco活化。然而，Rca的活性是不敏感的ADP抑制在拟南芥的拟南芥，rwt 43，它只表达拟南芥β-Rca，虽然不是在拟南芥的拟南芥，表达烟草样β-Rca。重组拟南芥beta-Rca的ATP水解对ADP的抑制比重组烟草beta-Rca的敏感性低得多。将烟草β-Rca中的17个氨基酸突变为相应的拟南芥残基降低了ADP敏感性。在植物中，Rubisco在低光照下失活，除了在拟南芥rwt 43拟南芥含有ADP不敏感的Rca。诱导CO2同化后，从低到高的辐照度的过渡是更迅速的rwt 43与植物相比，含有ADP敏感的Rca形式。与野生型拟南芥相比，rwt 43拟南芥在波动的光照条件下更快的光合诱导速率和更大的生长增强表明，Rca调节的操纵可能提供了一种在某些可变光环境中增强光合性能的策略。
Rubisco's catalytic chaperone, Rubisco activase (Rca), uses the energy from ATP hydrolysis to restore catalytic competence to Rubisco. In Arabidopsis (Arabidopsis thaliana), inhibition of Rca activity by ADP is fine tuned by redox regulation of the a-isoform. To elucidate the mechanism for Rca regulation in species containing only the redox-insensitive beta-isoform, the response of activity to ADP was characterized for different Rca forms. When assayed in leaf extracts, Rubisco activation was significantly inhibited by physiological ratios of ADP to ATP in species containing both alpha-Rca and beta-Rca (Arabidopsis and camelina [Camelina sativa]) or just the beta-Rca (tobacco [Nicotiana tabacum]). However, Rca activity was insensitive to ADP inhibition in an Arabidopsis transformant, rwt43, which expresses only Arabidopsis beta-Rca, although not in a transformant of Arabidopsis that expresses a tobacco-like beta-Rca. ATP hydrolysis by recombinant Arabidopsis beta-Rca was much less sensitive to inhibition by ADP than recombinant tobacco beta-Rca. Mutation of 17 amino acids in the tobacco beta-Rca to the corresponding Arabidopsis residues reduced ADP sensitivity. In planta, Rubisco deactivated at low irradiance except in the Arabidopsis rwt43 transformant containing an ADP-insensitive Rca. Induction of CO2 assimilation after transition from low to high irradiance was much more rapid in the rwt43 transformant compared with plants containing ADP-sensitive Rca forms. The faster rate of photosynthetic induction and a greater enhancement of growth under a fluctuating light regime by the rwt43 transformant compared with wild-type Arabidopsis suggests that manipulation of Rca regulation might provide a strategy for enhancing photosynthetic performance in certain variable light environments.