Pleiotropic effects of localized Rhodobacter capsulatus puf operon deletions on production of light-absorbing pigment-protein complexes.

AUTOR(ES)

Klug, G

RESUMO

The polycistronic puf operon of Rhodobacter capsulatus encodes protein components for the photosynthetic reaction center and one of the two antenna complexes involved in the capture of light energy. We report here that deletions within specific puf genes alter the synthesis and/or assembly in the photosynthetic membranes of pigment-protein complexes not affected genetically by the deletion. The pufX gene is required for normal ratios of antenna complexes, and its deletion results in an increase of membrane-bound light-harvesting I (LHI) complex-specific proteins. Expression of pufQ in strains deleted for the genes encoding the LHI and the photosynthetic reaction center (RC) yields a novel A868 peak that has not been associated with any of the pigment-protein complexes described previously. While deletions in the RC-coding region resulted in decreased LHI absorbance, no quantitative alteration in membrane-bound LHI protein was observed, suggesting that an intact RC complex is required for correct assembly of LHI in the membrane.

Documentos Relacionados

• The orf162b Sequence of Rhodobacter capsulatus Encodes a Protein Required for Optimal Levels of Photosynthetic Pigment-Protein Complexes
• Bacteriocin typing by leakage of ultraviolet light-absorbing material.
• Energy transfer in spectrally inhomogeneous light-harvesting pigment-protein complexes of purple bacteria.
• Directed mutagenesis of the Rhodobacter capsulatus puhA gene and orf 214: pleiotropic effects on photosynthetic reaction center and light-harvesting 1 complexes.
• Pigment-protein complexes from Rhodopseudomonas palustris: isolation, characterization, and reconstitution into liposomes.