共查询到20条相似文献,搜索用时 15 毫秒
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P. A. Fontán M. I. Voskuil M. Gomez D. Tan M. Pardini R. Manganelli L. Fattorini G. K. Schoolnik I. Smith 《Journal of bacteriology》2009,191(18):5628-5633
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Occurrence of a putative ancient-like isomerase involved in histidine and tryptophan biosynthesis 总被引:2,自引:0,他引:2
We report the occurrence of an isomerase with a putative (βα)8-barrel structure involved in both histidine and trypto-phan biosynthesis in Streptomyces coelicolor A3(2) and Mycobacterium tuberculosis HR37Rv. Deletion of a hisA homologue (SCO2050) putatively encoding N′-[(5′-phosphoribosyl)-formimino]-5 amino-imidazole-4-carboxamide ribonucleotide isomerase from the chromosome of S. coelicolor A3(2) generated a double auxotrophic mutant for histidine and tryptophan. The bifunctional gene SCO2050 and its orthologue Rv1603 from M. tuberculosis complemented both hisA and trpF mutants of Escherichia coli. Expression of the E. coli trpF gene in the S. coelicolor mutant only complemented the tryptophan auxo-trophy, and the hisA gene only complemented the histidine auxotrophy. The discovery of this enzyme, which has a broad-substrate specificity, has implications for the evolution of metabolic pathways and may prove to be important for understanding the evolution of the (βα)8-barrels. 相似文献
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Cristina Montero-Diez Padraig Deighan Joseph Osmundson Seth A. Darst Ann Hochschild 《Journal of bacteriology》2013,195(16):3621-3628
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Katsuhiko S. Murakami 《The Journal of biological chemistry》2013,288(13):9126-9134
Escherichia coli RNA polymerase (RNAP) is the most studied bacterial RNAP and has been used as the model RNAP for screening and evaluating potential RNAP-targeting antibiotics. However, the x-ray crystal structure of E. coli RNAP has been limited to individual domains. Here, I report the x-ray structure of the E. coli RNAP σ70 holoenzyme, which shows σ region 1.1 (σ1.1) and the α subunit C-terminal domain for the first time in the context of an intact RNAP. σ1.1 is positioned at the RNAP DNA-binding channel and completely blocks DNA entry to the RNAP active site. The structure reveals that σ1.1 contains a basic patch on its surface, which may play an important role in DNA interaction to facilitate open promoter complex formation. The α subunit C-terminal domain is positioned next to σ domain 4 with a fully stretched linker between the N- and C-terminal domains. E. coli RNAP crystals can be prepared from a convenient overexpression system, allowing further structural studies of bacterial RNAP mutants, including functionally deficient and antibiotic-resistant RNAPs. 相似文献
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