DIRECTED MUTATIONAL ANALYSIS OF BACTERIOCHLOROPHYLL-ALPHA BIOSYNTHESIS IN RHODOBACTER-CAPSULATUS
DIRECTED MUTATIONAL ANALYSIS OF BACTERIOCHLOROPHYLL-ALPHA BIOSYNTHESIS IN RHODOBACTER-CAPSULATUS
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DOI：
10.1006/jmbi.1994.1260
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发表时间：
1994-04-15
影响因子：
5.6
通讯作者：
BAUER, CE
中科院分区：
文献类型：
--
作者：
BOLLIVAR, DW;SUZUKI, JY;BAUER, CE
以前的研究已经确定，如果不是所有的基因所需的合成thRhodobacter capsulatus必需的光系统聚集在一个46 kb的区域的染色体称为光合作用基因簇。最近，赫斯特和他的同事对这一区域进行了完整的测序，揭示了23个开放阅读框架的存在，其中许多被认为与细菌叶绿素的合成有关。在这项研究中，我们进行了系统的定向突变分析的12个开放阅读框架的光合作用基因簇，以评估是否个别开放阅读框架有一个在色素生物合成的作用。该分析的结果表明，在七个开放的阅读框架中构建的突变导致细菌叶绿素生物合成的损失，伴随着特定的中间体的积累在镁-四吡咯生物合成途径。观察到一个突变导致细菌叶绿素生物合成的部分中断，导致细菌叶绿素的积累以及生物合成途径中的中间体。我们还观察到，在四个开放的阅读框架中构建的中断对色素合成没有明显的影响。这种分析的结果进行了讨论，就我们目前的理解的作用，这些开放的阅读框架的合成theR。被膜光系统
Previous studies have established that most if not all of the genes required for synthesis of theRhodobacter capsulatusessential photosystem are clustered on a 46 kb region of the chromosome known as the photosynthesis gene cluster. This region has recently been sequenced in its entirety by Hearst and co-workers, revealing the existence of 23 open reading frames, many of which are thought to be involved in the synthesis of bacteriochlorophyll. In this study we have undertaken a systematic directed mutational analysis of 12 open reading frames in the photosynthesis gene cluster to evaluate whether individual open reading frames have a role in photopigment biosynthesis. The results of this analysis demonstrate that mutations constructed in seven open reading frames resulted in a loss of bacteriochlorophyll biosynthesis, concomitant with the accumulation of specific intermediates in the Mg-tetrapyrrole biosynthetic pathway. One mutation was observed to result in partial disruption of bacteriochlorophyll biosynthesis, leading to the accumulation of bacteriochlorophyll as well as an intermediate in the biosynthetic pathway. We also observed that disruptions constructed in four open reading frames had no discernible effect on the synthesis of photopigments. The results of this analysis are discussed with regard to our current understanding of the role of each of these open reading frames in the synthesis of theR. capsulatusphotosystem.