期刊
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
卷 414, 期 2, 页码 141-149出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/S0003-9861(03)00171-1
关键词
Chlamydomonas reinhardtii; chloroplast enzyme; genetic engineering; photosynthesis; protein evolution; protein stability; ribulose-1,5-bisphosphate carboxylase/oxygenase
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of CO2 fixation in photosynthesis, but O-2 competes with CO2 for substrate ribulose 1,5-bisphosphate, leading to the loss of fixed carbon. Interest in genetically engineering improvements in carboxylation catalytic efficiency and CO2/O-2 specificity has focused on the chloroplast-encoded large subunit because it contains the active site. However, there is another type of subunit in the holoenzyme of plants, which, like the large subunit, is present in eight copies. The role of these nuclear-encoded small subunits in Rubisco structure and function is poorly understood. Small subunits may have originated during evolution to concentrate large-subunit active sites, but the extensive divergence of structures among prokaryotes, algae, and land plants seems to indicate that small subunits have more-specialized functions. Furthermore, plants and green algae contain families of differentially expressed small subunits, raising the possibility that these subunits may regulate the structure or function of Rubisco. Studies of interspecific hybrid enzymes have indicated that small subunits are required for maximal catalysis and, in several cases, contribute to CO2/O-2 specificity. Although small-subunit genetic engineering remains difficult in land plants, directed mutagenesis of cyanobacterial and green-algal genes has identified specific structural regions that influence catalytic efficiency and CO2/O-2 specificity. It is thus apparent that small subunits will need to be taken into account as strategies are developed for creating better Rubisco enzymes. (C) 2003 Elsevier Science (USA). All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据