Molecular, regulatory. and functional properties of alternative oxidases of non-angiosperm plants

生物电子传输链（ETC）为这个星球上的生命提供动力。所有植物细胞都含有线粒体，线粒体在将碳分子（如糖）转化为能量的同时使用氧气。植物线粒体包含两种呼吸途径：细胞色素c氧化酶途径，其存在于大多数生物体（包括人类）中，以及交替氧化酶（AOX）途径，其具有更有限的分布。尽管AOX的转录本、蛋白质水平和酶活性在各种环境胁迫下都会增加，但AOX的生理作用尚不清楚。我的研究项目的长期目标是了解呼吸电子传递在代谢和生理适应压力中的核心作用。这份提案描述了我的计划：（A）鉴定和检测非被子植物中的AOX基因（B）检验非被子植物AOX是单体的假设（由一个亚基组成），并且与被子植物AOX不同地调节，和（C）测试由不同AOX基因编码的AOX蛋白能够形成异源二聚体的假设，这将影响酶的催化特性。这些问题的答案将有助于阐明AOX的进化历史，AOX酶活性如何调节，AOX的结构，并确认AOX存在于所有植物中。我们的研究结果将有助于全面了解植物线粒体中的代谢灵活性如何使它们能够科普环境压力，从而有助于改善作物品种。我的研究计划允许在生物信息学，分子生物学，生物化学，生理学和进化的高素质人才的培训，并有助于说明如何比较和综合的方法来生物学可以促进知识的进步。

Biological electron transport chains (ETCs) power life on this planet. All plant cells contain mitochondria which use oxygen while converting carbon molecules, such as sugars, into energy. Plant mitochondria contain two respiratory pathways: the cytochrome c oxidase pathway, which is found in most organisms, including humans, and the alternative oxidase (AOX) pathway, which has a more limited distribution. Despite the fact that AOX transcripts, protein levels, and enzyme activity increase during a wide variety of environmental stresses, the physiological role of AOX is unknown. The long term goal of my research program is to understand the central role that respiratory electron transport plays in metabolic and physiological adaptations to stress. This proposal describes my plans to: (A) identify and examine AOX genes in non-angiosperm (non-flowering) plants and confirm that they are expressed as functional enzymes, (B) test the hypothesis that non-angiosperm plant AOXs are monomeric (composed of one subunit) and are regulated differently than angiosperm AOXs, and (C) test the hypothesis that AOX proteins encoded by different AOX genes are capable of forming heterodimers and that this will influence the catalytic properties of the enzyme.The answers to these questions will help to shed light on the evolutionary history of AOX and, how AOX enzyme activity is regulated, the structure of AOX, and to confirm that AOX is present in all plants. Our results will contribute to an overall understanding of how metabolic flexibility in the mitochondria of plants allows them to cope with environmental stress and can, thereby, contribute to the improvement of crop species. My research program allows for the training of highly qualified personnel in bioinformatics, molecular biology, biochemistry, physiology, and evolution and serves to illustrate how a comparative and integrative approach to biology can contribute to advancing knowledge.