Disease relevance of prrB

• A Rhodovulum sulfidophilum mutant lacking regA or regB was constructed [1].
• Structural and functional analyses of photosynthetic regulatory genes regA and regB from Rhodovulum sulfidophilum, Roseobacter denitrificans, and Rhodobacter capsulatus [1].
• Rhodobacter capsulatus regA- or regB-deficient mutants recovered the synthesis of a photosynthetic apparatus that still retained regulation by oxygen tension when complemented with reg genes from Rhodovulum sulfidophilum and Roseobacter denitrificans [1].

High impact information on prrB

• Four strains of 2.4.3 carrying mutations within the prrB gene were isolated in a screen for mutants unable to grow anaerobically on medium containing nitrite [2].
• It is also demonstrated that the extent of prrB gene expression is subject to the negative autoregulation of the PrrBA system [3].
• We report that under highly aerobic conditions, aberrant photosynthesis gene expression and spectral complex formation typical of cbb3- or RdxBH-deficient mutants were no longer observed when either prrA (encoding the response regulator of the Prr system) or prrB (encoding the presumed sensor kinase) was also deleted [4].
• In addition to regulating the expression of structural genes encoding enzymes of the primary pathway for CO2 fixation in R. sphaeroides, regB was also found to be required for the expression of a gene(s) important for the putative alternative CO2 fixation pathway(s) of this organism [5].
• The current investigation indicates that in addition to its role in the regulation of photosystem biosynthesis, regB (prrB) of R. sphaeroides is intimately involved in the positive regulation of the cbbI and cbbII Calvin cycle CO2 fixation operons [5].

Biological context of prrB

• Together, prrB and prrA provide the major signal involved in synthesis of the specialized intracytoplasmic membrane (ICM), harboring components essential to the light reactions of photosynthesis [6].
• Measurements of mRNA levels in cells containing the prrB78 mutation support the idea that prrB is a global regulator of photosynthesis gene expression [6].

Associations of prrB with chemical compounds

• This mutation is shown to reside in prrB, resulting in a leucine-to-proline change at position 78 in mutant PrrB (PRRB78) [6].
• It is thus apparent that regB is part of a two-component system and encodes a sensor kinase involved in the global regulation of both anoxygenic light-dependent- and oxygenic light-independent CO2 fixation as well as anoxygenic photosystem biosynthesis [5].

References