Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Photosynthesis Research |
| Vol/bind | 86 |
| Udgave nummer | 1-2 |
| Sider (fra-til) | 101-11 |
| Antal sider | 10 |
| ISSN | 0166-8595 |
| DOI | |
| Status | Udgivet - 2005 |
Bibliografisk note
Keywords: Bacterial Proteins; Bacteriochlorophylls; Carotenoids; Cell Fractionation; Chlorobium; Microscopy, Atomic Force; Microscopy, Electron; Mutation; Organelles; Protein Binding; Spectrum AnalysisAdgang til dokumentet
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Isolation and Characterization of Carotenosomes from a Bacteriochlorophyll c-less Mutant of Chlorobium tepidum. / Frigaard, Niels-Ulrik; Li, Hui; Martinsson, Peter; Das, Somes Kumar; Frank, Harry A; Aartsma, Thijs J; Bryant, Donald A.
I: Photosynthesis Research, Bind 86, Nr. 1-2, 2005, s. 101-11.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - Isolation and Characterization of Carotenosomes from a Bacteriochlorophyll c-less Mutant of Chlorobium tepidum
AU - Frigaard, Niels-Ulrik
AU - Li, Hui
AU - Martinsson, Peter
AU - Das, Somes Kumar
AU - Frank, Harry A
AU - Aartsma, Thijs J
AU - Bryant, Donald A
N1 - Keywords: Bacterial Proteins; Bacteriochlorophylls; Carotenoids; Cell Fractionation; Chlorobium; Microscopy, Atomic Force; Microscopy, Electron; Mutation; Organelles; Protein Binding; Spectrum Analysis
PY - 2005
Y1 - 2005
N2 - Chlorosomes are the light-harvesting organelles in photosynthetic green bacteria and typically contain large amounts of bacteriochlorophyll (BChl) c in addition to smaller amounts of BChl a, carotenoids, and several protein species. We have isolated vestigial chlorosomes, denoted carotenosomes, from a BChl c-less, bchK mutant of the green sulfur bacterium Chlorobium tepidum. The physical shape of the carotenosomes (86 +/- 17 nm x 66 +/- 13 nm x 4.3 +/- 0.8 nm on average) was reminiscent of a flattened chlorosome. The carotenosomes contained carotenoids, BChl a, and the proteins CsmA and CsmD in ratios to each other comparable to their ratios in wild-type chlorosomes, but all other chlorosome proteins normally found in wild-type chlorosomes were found only in trace amounts or were not detected. Similar to wild-type chlorosomes, the CsmA protein in the carotenosomes formed oligomers at least up to homo-octamers as shown by chemical cross-linking and immunoblotting. The absorption spectrum of BChl a in the carotenosomes was also indistinguishable from that in wild-type chlorosomes. Energy transfer from the bulk carotenoids to BChl a in carotenosomes was poor. The results indicate that the carotenosomes have an intact baseplate made of remarkably stable oligomeric CsmA-BChl a complexes but are flattened in structure due to the absence of BChl c. Carotenosomes thus provide a valuable material for studying the biogenesis, structure, and function of the photosynthetic antennae in green bacteria.
AB - Chlorosomes are the light-harvesting organelles in photosynthetic green bacteria and typically contain large amounts of bacteriochlorophyll (BChl) c in addition to smaller amounts of BChl a, carotenoids, and several protein species. We have isolated vestigial chlorosomes, denoted carotenosomes, from a BChl c-less, bchK mutant of the green sulfur bacterium Chlorobium tepidum. The physical shape of the carotenosomes (86 +/- 17 nm x 66 +/- 13 nm x 4.3 +/- 0.8 nm on average) was reminiscent of a flattened chlorosome. The carotenosomes contained carotenoids, BChl a, and the proteins CsmA and CsmD in ratios to each other comparable to their ratios in wild-type chlorosomes, but all other chlorosome proteins normally found in wild-type chlorosomes were found only in trace amounts or were not detected. Similar to wild-type chlorosomes, the CsmA protein in the carotenosomes formed oligomers at least up to homo-octamers as shown by chemical cross-linking and immunoblotting. The absorption spectrum of BChl a in the carotenosomes was also indistinguishable from that in wild-type chlorosomes. Energy transfer from the bulk carotenoids to BChl a in carotenosomes was poor. The results indicate that the carotenosomes have an intact baseplate made of remarkably stable oligomeric CsmA-BChl a complexes but are flattened in structure due to the absence of BChl c. Carotenosomes thus provide a valuable material for studying the biogenesis, structure, and function of the photosynthetic antennae in green bacteria.
U2 - 10.1007/s11120-005-1331-8
DO - 10.1007/s11120-005-1331-8
M3 - Journal article
C2 - 16172929
VL - 86
SP - 101
EP - 111
JO - Photosynthesis Research
JF - Photosynthesis Research
SN - 0166-8595
IS - 1-2
ER -