Proteins in chlorosomes: CsmI and CsmJ participate in light-dependent control of energy transfer in chlorosomes of chlorobaculum tepidum

Hui Li, Niels Ulrik Frigaard, Donald A. Bryant

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Chlorosomes of Chlorobaculum tepidum are formed from stacks of syn-anti coordinated bacteriochlorophyll c dimers, which form a suprastructure comprised of coaxial nanotubes and are surrounded by a glycolipid monolayer envelope containing 10 proteins. Three of these proteins, CsmI, CsmJ, and CsmX, have sequences very similar in their N-terminal domains to those of [2Fe-2S] ferredoxins of the adrenodoxin/putidaredoxin subfamily. The roles of these proteins in chlorosomes were studied in single-, double-, and triple-mutant strains. In each mutant, only the protein(s) corresponding to the mutated gene(s) was missing, and the amounts of other chlorosome proteins did not vary significantly. Electrophoretic analyses and immunoblotting showed that CsmX was much less abundant than CsmI or CsmJ. The growth rates and the pigment and isoprenoid quinone contents of isolated chlorosomes of the mutants were similar to wild-type values. Quenching and recovery of energy transfer in isolated chlorosomes and intact cells were studied by measuring fluorescence emission after exposure to or removal of oxygen. Oxygen-induced activation of the quencher in isolated chlorosomes or in intact cells was largely independent of CsmI and CsmJ. This may be because oxygen can diffuse across the chlorosome envelope easily and directly reacts with the quencher. However, CsmI and CsmJ were required to restore energy transfer fully after isolated chlorosomes were exposed to oxygen. Studies with intact cells suggested that cells contain both light-dependent and light-independent pathways for reducing the quenching species in chlorosomes and that CsmI and CsmJ are components of a light-dependent pathway.

Original languageEnglish (US)
Pages (from-to)1321-1330
Number of pages10
JournalBiochemistry
Volume52
Issue number8
DOIs
StatePublished - Feb 26 2013

Fingerprint

Energy Transfer
Energy transfer
Light
Oxygen
Proteins
Quenching
Adrenodoxin
Nanotubes
Glycolipids
Terpenes
Immunoblotting
Pigments
Dimers
Monolayers
Genes
Fluorescence
Chemical activation
Recovery
Growth

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

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title = "Proteins in chlorosomes: CsmI and CsmJ participate in light-dependent control of energy transfer in chlorosomes of chlorobaculum tepidum",
abstract = "Chlorosomes of Chlorobaculum tepidum are formed from stacks of syn-anti coordinated bacteriochlorophyll c dimers, which form a suprastructure comprised of coaxial nanotubes and are surrounded by a glycolipid monolayer envelope containing 10 proteins. Three of these proteins, CsmI, CsmJ, and CsmX, have sequences very similar in their N-terminal domains to those of [2Fe-2S] ferredoxins of the adrenodoxin/putidaredoxin subfamily. The roles of these proteins in chlorosomes were studied in single-, double-, and triple-mutant strains. In each mutant, only the protein(s) corresponding to the mutated gene(s) was missing, and the amounts of other chlorosome proteins did not vary significantly. Electrophoretic analyses and immunoblotting showed that CsmX was much less abundant than CsmI or CsmJ. The growth rates and the pigment and isoprenoid quinone contents of isolated chlorosomes of the mutants were similar to wild-type values. Quenching and recovery of energy transfer in isolated chlorosomes and intact cells were studied by measuring fluorescence emission after exposure to or removal of oxygen. Oxygen-induced activation of the quencher in isolated chlorosomes or in intact cells was largely independent of CsmI and CsmJ. This may be because oxygen can diffuse across the chlorosome envelope easily and directly reacts with the quencher. However, CsmI and CsmJ were required to restore energy transfer fully after isolated chlorosomes were exposed to oxygen. Studies with intact cells suggested that cells contain both light-dependent and light-independent pathways for reducing the quenching species in chlorosomes and that CsmI and CsmJ are components of a light-dependent pathway.",
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Proteins in chlorosomes : CsmI and CsmJ participate in light-dependent control of energy transfer in chlorosomes of chlorobaculum tepidum. / Li, Hui; Frigaard, Niels Ulrik; Bryant, Donald A.

In: Biochemistry, Vol. 52, No. 8, 26.02.2013, p. 1321-1330.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Proteins in chlorosomes

T2 - CsmI and CsmJ participate in light-dependent control of energy transfer in chlorosomes of chlorobaculum tepidum

AU - Li, Hui

AU - Frigaard, Niels Ulrik

AU - Bryant, Donald A.

PY - 2013/2/26

Y1 - 2013/2/26

N2 - Chlorosomes of Chlorobaculum tepidum are formed from stacks of syn-anti coordinated bacteriochlorophyll c dimers, which form a suprastructure comprised of coaxial nanotubes and are surrounded by a glycolipid monolayer envelope containing 10 proteins. Three of these proteins, CsmI, CsmJ, and CsmX, have sequences very similar in their N-terminal domains to those of [2Fe-2S] ferredoxins of the adrenodoxin/putidaredoxin subfamily. The roles of these proteins in chlorosomes were studied in single-, double-, and triple-mutant strains. In each mutant, only the protein(s) corresponding to the mutated gene(s) was missing, and the amounts of other chlorosome proteins did not vary significantly. Electrophoretic analyses and immunoblotting showed that CsmX was much less abundant than CsmI or CsmJ. The growth rates and the pigment and isoprenoid quinone contents of isolated chlorosomes of the mutants were similar to wild-type values. Quenching and recovery of energy transfer in isolated chlorosomes and intact cells were studied by measuring fluorescence emission after exposure to or removal of oxygen. Oxygen-induced activation of the quencher in isolated chlorosomes or in intact cells was largely independent of CsmI and CsmJ. This may be because oxygen can diffuse across the chlorosome envelope easily and directly reacts with the quencher. However, CsmI and CsmJ were required to restore energy transfer fully after isolated chlorosomes were exposed to oxygen. Studies with intact cells suggested that cells contain both light-dependent and light-independent pathways for reducing the quenching species in chlorosomes and that CsmI and CsmJ are components of a light-dependent pathway.

AB - Chlorosomes of Chlorobaculum tepidum are formed from stacks of syn-anti coordinated bacteriochlorophyll c dimers, which form a suprastructure comprised of coaxial nanotubes and are surrounded by a glycolipid monolayer envelope containing 10 proteins. Three of these proteins, CsmI, CsmJ, and CsmX, have sequences very similar in their N-terminal domains to those of [2Fe-2S] ferredoxins of the adrenodoxin/putidaredoxin subfamily. The roles of these proteins in chlorosomes were studied in single-, double-, and triple-mutant strains. In each mutant, only the protein(s) corresponding to the mutated gene(s) was missing, and the amounts of other chlorosome proteins did not vary significantly. Electrophoretic analyses and immunoblotting showed that CsmX was much less abundant than CsmI or CsmJ. The growth rates and the pigment and isoprenoid quinone contents of isolated chlorosomes of the mutants were similar to wild-type values. Quenching and recovery of energy transfer in isolated chlorosomes and intact cells were studied by measuring fluorescence emission after exposure to or removal of oxygen. Oxygen-induced activation of the quencher in isolated chlorosomes or in intact cells was largely independent of CsmI and CsmJ. This may be because oxygen can diffuse across the chlorosome envelope easily and directly reacts with the quencher. However, CsmI and CsmJ were required to restore energy transfer fully after isolated chlorosomes were exposed to oxygen. Studies with intact cells suggested that cells contain both light-dependent and light-independent pathways for reducing the quenching species in chlorosomes and that CsmI and CsmJ are components of a light-dependent pathway.

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EP - 1330

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SN - 0006-2960

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