TY - JOUR
T1 - Chlorobium tepidum
T2 - Insights into the structure, physiology, and metabolism of a green sulfur bacterium derived from the complete genome sequence
AU - Frigaard, Niels Ulrik
AU - Gomez Maqueo Chew, Aline
AU - Li, Hui
AU - Maresca, Julia A.
AU - Bryant, Donald A.
N1 - Funding Information:
As part of an effort to increase our understanding of bacterial diversity in general, and knowledge and interest in the green sulfur bacteria specifically, The Institute for Genome Research (TIGR; Rockville, Maryland) recently sequenced and annotated the Chl. tepidum genome as part of a program supported by the U.S. Department of Energy – Energy Biosciences (Eisen et al. 2002). In a related effort, the Joint Genome Institute (JGI; Walnut Creek, California) is now planning to sequence the combined genomes of ‘Chlorochromatium aggregatum’, a bacterial consortium composed of a green sulfur bacterial epibiont and a non-photosynthetic, motile β-proteobacterium. A draft genome sequence of the green filamentous bacterium Chloroflexus aurantiacus J-10-fl has also been produced by JGI-DOE. Cfx. aurantiacus is a member of the only other group of organisms, the phylum Chloroflexi, which synthesize BChl c and use chlorosomes as light-harvesting antennae (Garrity and Holt 2001a; Hanada and Pierson 2002). Sequence information can be obtained and analysis of these genomes can be performed on-line using the web-based analysis tools and data at the sites of TIGR (www.tigr.com), JGI-DOE (www.jgi.doe.gov), and the National Center for Biotechnology Information (NCBI) (www.ncbi.nlm.nih.gov). Additionally, the Chl. tepidum genome has recently been posted at Cyanobase, the cyanobacterial database of the Kazusa DNA Research Institute (Kazusa, Japan; www.kazusa.or.jp/cyano/Chlorobium).
Funding Information:
The research described in this article was supported by grant DE-FG02-94ER20137 from the US Department of Energy to D. A. B.
PY - 2003
Y1 - 2003
N2 - Green sulfur bacteria are obligate, anaerobic photolithoautotrophs that synthesize unique bacteriochlorophylls (BChls) and a unique light-harvesting antenna structure, the chlorosome. One organism, Chlorobium tepidum, has emerged as a model for this group of bacteria primarily due to its relative ease of cultivation and natural transformability. This review focuses on insights into the physiology and biochemistry of the green sulfur bacteria that have been derived from the recently completed analysis of the 2.15-Mb genome of Chl. tepidum. About 40 mutants of Chl. tepidum have been generated within the last 3 years, most of which have been made based on analyses of the genome. This has allowed a nearly complete elucidation of the biosynthetic pathways for the carotenoids and BChls in Chl. tepidum, which include several novel enzymes specific for BChl c biosynthesis. Facilitating these analyses, both BChl c and carotenoid biosynthesis can be completely eliminated in Chl. tepidum. Based particularly on analyses of mutants lacking chlorosome proteins and BChl c, progress has also been made in understanding the structure and biogenesis of chlorosomes. In silica analyses of the presence and absence of genes encoding components involved in electron transfer reactions and carbon assimilation have additionally revealed some of the potential physiological capabilities, limitations, and peculiarities of Chl. tepidum. Surprisingly, some structural components and biosynthetic pathways associated with photosynthesis and energy metabolism in Chl. tepidum are more similar to those in cyanobacteria and plants than to those in other groups of photosynthetic bacteria.
AB - Green sulfur bacteria are obligate, anaerobic photolithoautotrophs that synthesize unique bacteriochlorophylls (BChls) and a unique light-harvesting antenna structure, the chlorosome. One organism, Chlorobium tepidum, has emerged as a model for this group of bacteria primarily due to its relative ease of cultivation and natural transformability. This review focuses on insights into the physiology and biochemistry of the green sulfur bacteria that have been derived from the recently completed analysis of the 2.15-Mb genome of Chl. tepidum. About 40 mutants of Chl. tepidum have been generated within the last 3 years, most of which have been made based on analyses of the genome. This has allowed a nearly complete elucidation of the biosynthetic pathways for the carotenoids and BChls in Chl. tepidum, which include several novel enzymes specific for BChl c biosynthesis. Facilitating these analyses, both BChl c and carotenoid biosynthesis can be completely eliminated in Chl. tepidum. Based particularly on analyses of mutants lacking chlorosome proteins and BChl c, progress has also been made in understanding the structure and biogenesis of chlorosomes. In silica analyses of the presence and absence of genes encoding components involved in electron transfer reactions and carbon assimilation have additionally revealed some of the potential physiological capabilities, limitations, and peculiarities of Chl. tepidum. Surprisingly, some structural components and biosynthetic pathways associated with photosynthesis and energy metabolism in Chl. tepidum are more similar to those in cyanobacteria and plants than to those in other groups of photosynthetic bacteria.
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U2 - 10.1023/B:PRES.0000004310.96189.b4
DO - 10.1023/B:PRES.0000004310.96189.b4
M3 - Review article
AN - SCOPUS:0347596598
SN - 0166-8595
VL - 78
SP - 93
EP - 117
JO - Photosynthesis research
JF - Photosynthesis research
IS - 2
ER -