Regulation of carbon dioxide fixation in the chemoautotroph Xanthobacter flavus
Regulation of carbon dioxide fixation in the chemoautotroph Xanthobacter flavus
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发表时间：
2000
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通讯作者：
G. Keulen;W. Meijer
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作者：
G. Keulen;W. Meijer
过去十年，我们对化能自养细菌的生理学、生态学和分子生物学的理解取得了重大进展。许多生态系统依赖于自由生活或共生化能自养生物的CO 2 固定。 CO 2 在化能自养生物中的固定通过卡尔文-本森-巴沙姆循环发生。该循环的特征在于三种独特的酶活性：核酮糖二磷酸羧化酶/加氧酶、磷酸核酮糖激酶和景天庚酮糖二磷酸酶。核酮糖二磷酸羧化酶/加氧酶通常存在于细胞质中，但许多细菌将大部分酶包装到多面体细胞器（羧基体）中。羧基体基因位于 cbb 基因附近，cbb 基因通常但并非总是聚集在大操纵子中。碳和还原底物的可用性与 LysR 型转录调节因子 CbbR 一起控制 cbb 基因的表达。还可能涉及其他调节蛋白。所有这些以及相关主题都将在本次评论中详细讨论。
The last decade has seen significant advances in our understanding of the physiology, ecology, and molecular biology of chemoautotrophic bacteria. Many ecosystems are dependent on CO 2 fixation by either free-living or symbiotic chemoautotrophs. CO 2 fixation in the chemoautotroph occurs via the Calvin-Benson-Bassham cycle. The cycle is characterized by three unique enzymatic activities: ribulose bisphosphate carboxylase/oxygenase, phosphoribulokinase, and sedoheptulose bisphosphatase. Ribulose bisphosphate carboxylase/oxygenase is commonly found in the cytoplasm, but a number of bacteria package much of the enzyme into polyhedral organelles, the carboxysomes. The carboxysome genes are located adjacent to cbb genes, which are often, but not always, clustered in large operons. The availability of carbon and reduced substrates control the expression of cbb genes in concert with the LysR-type transcriptional regulator, CbbR. Additional regulatory proteins may also be involved. All of these, as well as related topics, are discussed in detail in this review.