Interplay between formation of photosynthetic complexes and expression of genes for iron–sulfur cluster assembly in Rhodobacter sphaeroides?

Abstract

Formation of photosynthetic complexes leads to a higher demand for Fe–S clusters. We hypothesized that in the facultative phototrophic alpha-proteobacterium Rhodobacter sphaeroides expression of the isc-suf operon for Fe–S cluster formation may be increased under conditions that promote formation of photosynthetic complexes and that, vice versa, lack of the IscR regulator may also affect photosynthesis gene expression. To test this hypothesis, we monitored the activities of the isc-suf sense and anti-sense promoters under different growth conditions and in mutants which are impaired in formation of photosynthetic complexes. We also tested expression of photosynthesis genes in a mutant lacking the IscR regulator. Our results are not in agreement with a co-regulation of the Isc-Suf system and the photosynthetic apparatus at level of transcription. We provide evidence that, coordination of the systems occurs at post-transcriptional levels. Increased levels of isc-suf mRNAs under conditions promoting formation of photosynthetic complexes are due to higher RNA stability.

Cyclopentadienyl iron dicarbonyl styrene chalcogenosulfonates: synthesis and structure of CpFe(CO)2SeSO2CH=CHPh

“…Iron complexes incorporating sulfur or selenium ligands stimulate increasing interest due to their importance in biological systems, [1][2][3][4] their relevance to catalytic processes [5][6][7][8][9] and in the development of material science. [10][11][12][13] Iron-sulfur proteins are required for many biological processes.…”

“…They are involved in numerous cellular processes like respiration, photosynthesis, metabolic reactions, nitrogen fixation, DNA replication and repair, regulation of gene expression or t-RNA modifications. [1][2][3][4] The influence of the incorporation of sulfur or selenium atoms into the structure of [FeFe]-hydrogenase models, has been investigated on their activity for hydrogen production. [5][6][7][8][9] Iron sulfide nanomaterials have been used as electrocatalysts for water-splitting leading to hydrogen evolution.…”