Affiliation:
1. Department of Chemistry and Biochemistry, P.O. Box 871604, Arizona State University, Tempe, Arizona 85287-1604
2. Departments of Biology and Chemistry, Washington University, St. Louis, Missouri 63130
Abstract
ABSTRACT
“
Candidatus
Chlorothrix halophila” is a recently described halophilic, filamentous, anoxygenic photoautotroph (J. A. Klappenbach and B. K. Pierson, Arch. Microbiol.
181:
17-25, 2004) that was enriched from the hypersaline microbial mats at Guerrero Negro, Mexico. Analysis of the photosynthetic apparatus by negative staining, spectroscopy, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the photosynthetic apparatus in this organism has similarities to the photosynthetic apparatus in both the
Chloroflexi
and
Chlorobi
phyla of green photosynthetic bacteria. The chlorosomes were found to be ellipsoidal and of various sizes, characteristics that are comparable to characteristics of chlorosomes in other species of green photosynthetic bacteria. The absorption spectrum of whole cells was dominated by the chlorosome bacteriochlorophyll
c
(BChl
c
) peak at 759 nm, with fluorescence emission at 760 nm. A second fluorescence emission band was observed at 870 nm and was tentatively attributed to a membrane-bound antenna complex. Fluorescence emission spectra obtained at 77 K revealed another complex that fluoresced at 820 nm, which probably resulted from the chlorosome baseplate complex. All of these results suggest that BChl
c
is present in the chlorosomes of “
Ca
. Chlorothrix halophila,” that BChl
a
is present in the baseplate, and that there is a membrane-bound antenna complex. Analysis of the proteins in the chlorosomes revealed an ∼6-kDa band, which was found to be related to the BChl
c
binding protein CsmA found in other green bacteria. Overall, the absorbance and fluorescence spectra of “
Ca
. Chlorothrix halophila” revealed an interesting mixture of photosynthetic characteristics that seemed to have properties similar to properties of both phyla of green bacteria when they were compared to the photosynthetic characteristics of
Chlorobium tepidum
and
Chloroflexus aurantiacus
.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference42 articles.
1. Beatty, J. T., J. Overmann, M. T. Lince, A. K. Manske, A. S. Lang, R. E. Blankenship, C. L. Van Dover, T. A. Martinson, and F. G. Plumley. 2005. An obligately photosynthetic bacterial anaerobe from a deep-sea hydrothermal vent. Proc. Natl. Acad. Sci. USA 102 : 9306-9310.
2. Betti, J. A., R. E. Blankenship, L. V. Natarajan, L. C. Dickinson, and R. C. Fuller. 1982. Antenna organization and evidence for the function of a new antenna pigment species in the green photosynthetic bacterium Chloroflexus aurantiacus. Biochim. Biophys. Acta 680 : 194-201.
3. Molecular mechanisms of photosynthesis. 2002
4. Blankenship, R. E., and K. Matsuura. 2003. Antenna complexes from green photosynthetic bacteria, p. 195-217. In B. R. Green and W. W. Parson (ed.), Light harvesting antennas. Kluwer, Dordrecht, The Netherlands.
5. Blankenship, R. E., J. M. Olson, and M. Miller. 1995. Antenna complexes from green photosynthetic bacteria, p. 399-435. In R. E. Blankenship, M. T. Madigan, and C. E. Bauer (ed.), Anoxygenic photosynthetic bacteria. Kluwer, Dordrecht, The Netherlands.
Cited by
10 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献