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Title A singular PpaA/AerR-like protein in Rhodospirillum rubrum rules beyond the boundaries of photosynthesis in response to the intracellular redox state
ID_Doc 14216
Authors Godoy, MS; de Miguel, SR; Prieto, MA
Title A singular PpaA/AerR-like protein in Rhodospirillum rubrum rules beyond the boundaries of photosynthesis in response to the intracellular redox state
Year 2023
Published Msystems, 8, 6
DOI 10.1128/msystems.00702-23
Abstract Photosynthesis (PS) in purple non-Sulfur bacteria (PNSB) is strictly controlled to avoid energy consumption and to prevent oxidative stress when oxygen is present. PpsR, a transcriptional repressor encoded in the photosynthesis gene cluster (PGC), is one of the main players in the regulation of PS-related genes. In some cases, PpsR does not sense the environmental cue by itself but delegates this task to other proteins like PpaA/AerR anti-repressors, which can ultimately affect PpsR affinity to some promoter regions. In this work, the effects of locus Rru_A0625 product (HP1) on PS regulation of Rhodospirillum rubrum were studied by mutation/complementation and transcriptomic strategies. Rru_A0625 is located next to ppsR gene, just like other PpaA/AerR members, and its deletion annuls pigment synthesis in dark micro/anaerobic growth conditions. HP1 shows similarity to PpaA/AerR anti-repressors family, although it does not possess their typical cobalamin binding domain. A transcriptomic analysis of Rru_A0625 deletion mutant showed that HP1 not only has effects on bacteriochlorophyll and carotenoid biosynthesis, but also many other biological processes in the cell. The most notorious is the impact on the transcription of the nitrogenase complex components and accessory proteins. Our results suggest that this new member of the PpaA/AerR family has evolved losing the canonical cobalamin binding domain, but not the redox sensing capability, conserving a not fully understood mechanism of PS regulation.
Author Keywords Rhodospirillum rubrum; photosynthesis; AerR/PpaA; Purple Non-Sulphur Bacteria
Index Keywords Index Keywords
Document Type Other
Open Access Open Access
Source Science Citation Index Expanded (SCI-EXPANDED)
EID WOS:001114833000001
WoS Category Microbiology
Research Area Microbiology
PDF https://doi.org/10.1128/msystems.00702-23
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