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Revisiting Trade-offs between Rubisco Kinetic Parameters

机译：Rubisco动力学参数之间重新审视权衡

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摘要

Rubisco is the primary carboxylase of the Calvin cycle, the most abundant enzyme in the biosphere, and one of the best-characterized enzymes. On the basis of correlations between Rubisco kinetic parameters, it is widely posited that constraints embedded in the catalytic mechanism enforce trade-offs between CO2 specificity, S-C/O, and maximum carboxylation rate, k(cat,C). However, the reasoning that established this view was based on data from approximate to 20 organisms. Here, we re-examine models of trade-offs in Rubisco catalysis using a data set from approximate to 300 organisms. Correlations between kinetic parameters are substantially attenuated in this larger data set, with the inverse relationship between k(cat,C) and S-C/O being a key example. Nonetheless, measured kinetic parameters display extremely limited variation, consistent with a view of Rubisco as a highly constrained enzyme. More than 95% of k(cat,C) values are between 1 and 10 s(-1), and no measured k(cat,C) exceeds 15 s(-1). Similarly, S-C/O varies by only 30% among Form I Rubiscos and <10% among C-3 plant enzymes. Limited variation in S-C/O forces a strong positive correlation between the catalytic efficiencies (k(cat)/K-M) for carboxylation and oxygenation, consistent with a model of Rubisco catalysis in which increasing the rate of addition of CO2, to the enzyme-substrate complex requires an equal increase in the O-2 addition rate. Altogether, these data suggest that Rubisco evolution is tightly constrained by the physicochemical limits of CO2/O-2 discrimination.
机译：Rubisco是Calvin循环的主要羧基化酶，生物圈中最丰富的酶，以及最佳特征的酶。在Rubisco动力学参数之间的相关性的基础上，广泛定位嵌入在催化机制中的约束在CO 2特异性，S-C / O和最大羧化率，K（猫，C）之间强制执行折衷。然而，建立这种观点的推理是基于近似20个生物的数据。在这里，我们使用从近似300个生物体的数据重新检查Rubisco催化中的权衡模型。动力学参数之间的相关性在该较大的数据集中基本上衰减，具有K（CAT，C）和S-C / O之间的反向关系是一个关键示例。尽管如此，测量的动力学参数显示出极限的变化，与Rubisco视图为高度约束的酶。超过95％的K（CAT，C）值介于1到10秒（-1）之间，并且没有测量的K（CAT，C）超过15s（-1）。类似地，S-C / O在I rubiscos形式中仅在30％之间变化，并且在C-3植物酶中的<10％之间变化。 SC / O的有限变化强制羧化和氧合的催化效率（K（猫）/ km）之间的强阳性相关性，与Rubisco催化模型一致，从中增加CO 2的加入速率 - 基质复杂需要同等增加的O-2添加率。总之，这些数据表明，Rubisco Evolution严重限制了CO2 / O-2歧视的物理化学限制。

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  • 来源
    《Biochemistry》 |2019年第31期|共12页
  • 作者

    Flamholz Avi I; Prywes Noam; Moran Uri; David Dan; Bar-On Yinon M.; Oltrogge Luke M.; Alves Rui; Savage David; Milo Ron;

  • 作者单位

    Univ Calif Berkeley Dept Mol &

    Cell Biol 229 Stanley Hall Berkeley CA 94720 USA;

    Univ Calif Berkeley Innovat Genom Inst Berkeley CA 94704 USA;

    Weizmann Inst Sci Dept Plant &

    Environm Sci IL-76100 Rehovot Israel;

    Weizmann Inst Sci Dept Plant &

    Environm Sci IL-76100 Rehovot Israel;

    Weizmann Inst Sci Dept Plant &

    Environm Sci IL-76100 Rehovot Israel;

    Univ Calif Berkeley Dept Mol &

    Cell Biol 229 Stanley Hall Berkeley CA 94720 USA;

    IRBLIeida Inst Biomed Res Lleida Lleida 25198 Catalunya Spain;

    Univ Calif Berkeley Dept Mol &

    Cell Biol 229 Stanley Hall Berkeley CA 94720 USA;

    Weizmann Inst Sci Dept Plant &

    Environm Sci IL-76100 Rehovot Israel;

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  • 正文语种 eng
  • 中图分类 生物化学;
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