The Carbon Dioxide Concentrating Mechanism of Chlamydomonas reinhardtii

单细胞藻类，包括莱茵衣藻（Chlamydomonas reinhardtii），具有内部浓缩二氧化碳的能力，使这些生物能够在非常低的外部二氧化碳浓度下进行光自养生长。这种二氧化碳浓缩机制是可诱导的；它只存在于在限制二氧化碳条件下生长的细胞中。Moroney博士已经证明，具有二氧化碳浓缩机制的细胞具有低二氧化碳诱导多肽LIP-36，存在于叶绿体包膜中。他还发现了6个在低二氧化碳环境下生长的基因。其中两个基因，1113和215，编码假定的跨膜蛋白。最近，他获得了编码LIP-36的基因，并鉴定了一个编码内部碳酸酐酶的基因。在该奖项中，Moroney博士将通过三种方法研究莱茵哈蒂菌的二氧化碳浓缩机制。在第一种方法中，他将继续描述一些已确定的基因和蛋白质。第二种方法是与约翰霍普金斯大学的Richard E. McCarty博士合作，利用叶绿体包膜囊泡来测量无机碳的运输。第三种方法将是利用细胞分离和免疫定位来定位rubisco和新发现的碳酸酐酶在reinhardtii叶绿体内。这一转运系统的蛋白质特征将增加我们对藻类低二氧化碳调节和叶绿体在这种光合适应中的作用的理解。藻类光合作用为地球的能量循环贡献了很大一部分。对其潜在机制的研究将有助于我们对全球变化的理解。

9632087 Moroney Unicellular algae, including Chlamydomonas reinhardtii, have the capacity to concentrate carbon dioxide internally, allowing these organisms to grow photoautotrophically at very low external carbon dioxide concentrations. This carbon dioxide concentrating mechanism is inducible; it is present only in cells that have been grown with limiting carbon dioxide conditions. Dr. Moroney has shown that cells with the carbon dioxide concentrating mechanism have the low carbon dioxide-inducible polypeptide, LIP-36, present in the chloroplast envelope. He also has identified six genes that are specifically induced by growth on low carbon dioxide. Two of these genes, 1113 ans 215, encode putative transmembrane proteins. Recently he has obtained the gene encoding LIP-36 and has identified a gene encoding an internal carbonic anhydrase. In this award, Dr. Moroney will study the carbon dioxide concentrating mechanism in C. reinhardtii by using three approaches. In the first approach he will continue to characterize some of the genes and proteins identified. The second approach will be to measure inorganic carbon transport using chloroplast envelope vesicles in collaboration with Dr. Richard E. McCarty, Johns Hopkins University. The third approach will be to use cellular fractionation and immunolocalization to localize rubisco and the newly discovered carbonic anhydrase within the chloroplast of C. reinhardtii. The characterization of the proteins of this transport system will increase our understanding of the low carbon dioxide adjustment in algae and the role of the chloroplast in this photosynthetic adaptation. Algal photosynthesis contributes a major portion of the earth's energy cycle. Studies of its underlying mechanisms will contribute to our understanding of global change.