Rubisco adaptation is more limited by phylogenetic constraint than by catalytic trade-off
Rubisco adaptation is more limited by phylogenetic constraint than by catalytic trade-off
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Rubisco 适应更多地受到系统发育约束而不是催化权衡的限制
DOI：
10.1101/2020.09.15.298075
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Bouvier J
中科院分区：
文献类型：
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作者：
Bouvier J
Rubisco 吸收二氧化碳形成糖，为地球上的生命提供燃料。不同物种的 rubisco 动力学特征之间的相关性表明，rubisco 的适应受到催化权衡的高度限制。然而，这些分析没有考虑所分析酶的系统发育背景。因此，观察到的相关性可能是 rubisco 动力学中系统发育信号的存在以及采样物种之间的系统发育关系的人为因素。在这里，我们对 Rubisco 动力学进行了系统发育解析分析，结果表明 Rubisco 动力学特征存在显着的系统发育信号。我们重新评估了这种系统发育信号的催化权衡程度，发现所有信号都减弱了。经过系统发育校正后，在 CO2 的米氏常数和羧化酶周转率 (∼21–37%) 之间以及 CO2 和 O2 的米氏常数之间 (∼9–19%) 之间观察到最大的催化权衡。所有其他催化权衡均大幅减弱，以至于它们是边际的（<9%）或不显着。这种对 rubisco 动力学进化进行系统发育解析的分析还确定了伴随 C4 光合作用进化而发生的动力学变化。最后，我们表明，在限制 rubisco 动力学演化方面，系统发育约束比催化权衡发挥了更大的作用。因此，尽管有强有力的证据表明存在一些催化权衡，但与所有催化权衡的联合作用相比，rubisco适应更多地受到系统发育约束的限制。
Rubisco assimilates CO2to form the sugars that fuel life on earth. Correlations between rubisco kinetic traits across species have led to the proposition that rubisco adaptation is highly constrained by catalytic trade-offs. However, these analyses did not consider the phylogenetic context of the enzymes that were analyzed. Thus, it is possible that the correlations observed were an artefact of the presence of phylogenetic signal in rubisco kinetics and the phylogenetic relationship between the species that were sampled. Here, we conducted a phylogenetically resolved analysis of rubisco kinetics and show that there is a significant phylogenetic signal in rubisco kinetic traits. We re-evaluated the extent of catalytic trade-offs accounting for this phylogenetic signal and found that all were attenuated. Following phylogenetic correction, the largest catalytic trade-offs were observed between the Michaelis constant for CO2and carboxylase turnover (∼21–37%), and between the Michaelis constants for CO2and O2(∼9–19%), respectively. All other catalytic trade-offs were substantially attenuated such that they were marginal (<9%) or non-significant. This phylogenetically resolved analysis of rubisco kinetic evolution also identified kinetic changes that occur concomitant with the evolution of C4photosynthesis. Finally, we show that phylogenetic constraints have played a larger role than catalytic trade-offs in limiting the evolution of rubisco kinetics. Thus, although there is strong evidence for some catalytic trade-offs, rubisco adaptation has been more limited by phylogenetic constraint than by the combined action of all catalytic trade-offs.