Proteins Catalysts of Fermentation Respiration and Photosynthesis in Cyanobacteria and Algae

对参与光合作用的蛋白质的研究指出了一条重要的发酵途径，它允许蓝藻在黑暗的厌氧条件下生存。对一些蓝藻和藻类中丰富的可溶性、低潜势细胞色素c的研究表明，这种细胞色素将铁氧还蛋白与氢酶联系起来，支持碳水化合物储备的发酵。有待检验的细胞色素功能假说是基于来自酶学和细胞生理学的数据。这必须通过基因缺失技术来证实。建议对催化剂相互作用的化学和相关基因的表达调控进行研究。该途径的不同组催化剂存在于细胞的不同隔室中。这些蛋白质的结构和功能将被研究。有证据表明，类胡萝卜素蛋白可能起到保护蓝藻在强光下免受光破坏的作用。为了扩展和澄清这一假设，提出了一些实验。细胞色素C6可能是光合作用和呼吸电子传递的催化剂。我们已经发现了这种催化剂的三种异构体。PI将研究这些形式的化学基础，并寻找在不同的催化功能或靶向细胞的不同隔室中的作用。

Studies of proteins involved in photosynthesis point to an important pathway of fermentation which permits survival of cyanobacteria and algae under dark, anaerobic conditions. Studies of the soluble, low potential cytochrome c which is abundant in some cyanobacteria and algae suggest that this cytochrome links ferredoxin to hydrogenase in supporting the fermentation of carbohydrate reserves. The hypothesis of cytochrome function to be tested is based on data from enzymology and cell physiology. It must be confirmed by the techniques of gene deletion. Studies of the chemistry of catalyst interaction and of regulation of expression of the genes involved are proposed. Different sets of catalysts of this pathway were present in different compartments of the cell. The structure and function of these proteins will be studied. There is evidence that a carotenoid protein may function to protect cyanobacteria from photodestruction in bright light. Experiments are proposed to extend and clarify this hypothesis. Cytochrome c6 may be a catalyst of both photosynthetic and respiratory electron transport. We have found three isoforms of this catalyst. The PI will study the chemical basis for these forms and look for roles in distinct catalytic functions or in targeting to different compartments of the cell.