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Soulier N, Walters K, Laremore TN, Shen G, Golbeck JH, Bryant DA. Acclimation of the photosynthetic apparatus to low light in a thermophilic Synechococcus sp. strain. PHOTOSYNTHESIS RESEARCH 2022; 153:21-42. [PMID: 35441927 DOI: 10.1007/s11120-022-00918-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
Depending upon their growth responses to high and low irradiance, respectively, thermophilic Synechococcus sp. isolates from microbial mats associated with the effluent channels of Mushroom Spring, an alkaline siliceous hot spring in Yellowstone National Park, can be described as either high-light (HL) or low-light (LL) ecotypes. Strains isolated from the bottom of the photic zone grow more rapidly at low irradiance compared to strains isolated from the uppermost layer of the mat, which conversely grow better at high irradiance. The LL-ecotypes develop far-red absorbance and fluorescence emission features after growth in LL. These isolates have a unique gene cluster that encodes a putative cyanobacteriochrome denoted LcyA, a putative sensor histidine kinase; an allophycocyanin (FRL-AP; ApcD4-ApcB3) that absorbs far-red light; and a putative chlorophyll a-binding protein, denoted IsiX, which is homologous to IsiA. The emergence of FRL absorbance in LL-adapted cells of Synechococcus sp. strain A1463 was analyzed in cultures responding to differences in light intensity. The far-red absorbance phenotype arises from expression of a novel antenna complex containing the FRL-AP, ApcD4-ApcB3, which is produced when cells were grown at very low irradiance. Additionally, the two GAF domains of LcyA were shown to bind phycocyanobilin and a [4Fe-4S] cluster, respectively. These ligands potentially enable this photoreceptor to respond to a variety of environmental factors including irradiance, redox potential, and/or oxygen concentration. The products of the gene clusters specific to LL-ecotypes likely facilitate growth in low-light environments through a process called Low-Light Photoacclimation.
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Affiliation(s)
- Nathan Soulier
- Department of Biochemistry and Molecular Biology, S-002 Frear Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Karim Walters
- Department of Biochemistry and Molecular Biology, S-002 Frear Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Tatiana N Laremore
- Proteomics and Mass Spectrometry Core Facility, Huck Institute for the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, S-002 Frear Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, S-002 Frear Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, S-002 Frear Laboratory, The Pennsylvania State University, University Park, PA, 16802, USA.
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Pardoux R, Dolla A, Aubert C. Metal-containing PAS/GAF domains in bacterial sensors. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Fiévet A, Merrouch M, Brasseur G, Eve D, Biondi EG, Valette O, Pauleta SR, Dolla A, Dermoun Z, Burlat B, Aubert C. OrpR is a σ 54 -dependent activator using an iron-sulfur cluster for redox sensing in Desulfovibrio vulgaris Hildenborough. Mol Microbiol 2021; 116:231-244. [PMID: 33595838 PMCID: PMC8359166 DOI: 10.1111/mmi.14705] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 02/15/2021] [Accepted: 02/15/2021] [Indexed: 01/15/2023]
Abstract
Enhancer binding proteins (EBPs) are key players of σ54 -regulation that control transcription in response to environmental signals. In the anaerobic microorganism Desulfovibrio vulgaris Hildenborough (DvH), orp operons have been previously shown to be coregulated by σ54 -RNA polymerase, the integration host factor IHF and a cognate EBP, OrpR. In this study, ChIP-seq experiments indicated that the OrpR regulon consists of only the two divergent orp operons. In vivo data revealed that (i) OrpR is absolutely required for orp operons transcription, (ii) under anaerobic conditions, OrpR binds on the two dedicated DNA binding sites and leads to high expression levels of the orp operons, (iii) increasing the redox potential of the medium leads to a drastic down-regulation of the orp operons expression. Moreover, combining functional and biophysical studies on the anaerobically purified OrpR leads us to propose that OrpR senses redox potential variations via a redox-sensitive [4Fe-4S]2+ cluster in the sensory PAS domain. Overall, the study herein presents the first characterization of a new Fe-S redox regulator belonging to the σ54 -dependent transcriptional regulator family probably advantageously selected by cells adapted to the anaerobic lifestyle to monitor redox stress conditions.
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Affiliation(s)
| | | | | | - Danaé Eve
- Aix Marseille Univ, CNRS, LCB, Marseille, France
| | | | | | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Dept. Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Alain Dolla
- Aix Marseille Univ, Toulon Univ, CNRS, IRD, MIO, Marseille, France
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