Temperature, photosynthesis, and rubisco

自工业革命以来，大气中二氧化碳水平的上升与上个世纪的强烈气候变暖有关。 了解光合作用对温度和其他环境因素变化的反应是预测自然植物群落和农业物种对全球变化反应的重要组成部分。 光合作用通常有一个热最佳条件，可以根据特定的物种及其代谢进行广义或狭义的定义;光合作用在高于或低于这个最佳条件时明显下降。 目前，在文献中有相当大的争论，导致减少光合CO2固定以上的热最佳的因素。 这里提出的研究将使用转基因植物来解决这些问题，这些转基因植物具有减少的Rubisco，主要的CO2固定酶。 此外，这项研究将探索光合作用对温度的适应反应，特别是那些影响CO2受体分子再生的反应。 从长远来看，我的研究将集中在Rubisco本身。 Rubisco是地球上最丰富的蛋白质，但其动力学性质相对较差，其功能的几个方面仍不清楚。 我将与国外合作者一起，在黄曲霉属中测定这种酶的生化参数，以研究这些性状的进化。 我们将结合酶的结构研究，包括蛋白质测序和X射线晶体学，以澄清Rubisco的结构和功能之间的联系。

The rise in levels of atmospheric CO2 since the industrial revolution has been linked to strong climate warming in the last century.  Understanding the response of photosynthesis to variation in temperature and other environmental factors is a vital component of predicting the response of natural plant communities and agricultural species to global change.  Photosynthesis typically has a thermal optimum that can be broadly or narrowly defined depending on the particular species and its metabolism; photosynthesis declines appreciably above or below this optimum.  At present there is considerable debate in the literature regarding the factors that lead to the reduction in photosynthetic CO2 fixation above the thermal optimum.  The research proposed here will address these issues using transgenic plants that have reduced amounts of Rubisco, the principle CO2-fixing enzyme.  In addition, this research will explore the acclimation responses of photosynthesis to temperature, in particular those reactions that effect the regeneration of the CO2-acceptor molecules.  In the long term my research will focus on Rubisco itself.  Rubisco is the most abundant protein on Earth, but it has relatively poor kinetic qualities and several aspects of its function remain unclear.  In conjunction with overseas collaborators, I will characterise the biochemical parameters of this enzyme within the genus Flaveria to examine the evolution of these traits.  We will incorporate structural studies of the enzyme, including protein sequencing and x-ray crystallography, in order to clarify the links between the structure and function of Rubisco.