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Klein R, Brehm J, Wissig J, Heermann R, Unden G. A signaling complex of adenylate cyclase CyaC of Sinorhizobium meliloti with cAMP and the transcriptional regulators Clr and CycR. BMC Microbiol 2023; 23:236. [PMID: 37633907 PMCID: PMC10463352 DOI: 10.1186/s12866-023-02989-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/21/2023] [Indexed: 08/28/2023] Open
Abstract
BACKGROUND Adenylate cyclases (ACs) generate the second messenger cyclic AMP (cAMP), which is found in all domains of life and is involved in the regulation of various cell physiological and metabolic processes. In the plant symbiotic bacterium Sinorhizobium meliloti, synthesis of cAMP by the membrane-bound AC CyaC responds to the redox state of the respiratory chain and the respiratory quinones. However, nothing is known about the signaling cascade that is initiated by cAMP produced by CyaC. RESULTS Here, the CRP-like transcriptional regulator Clr and the TetR-like regulator CycR (TR01819 protein) were identified to interact with CyaC using the bacterial two-hybrid system (BACTH), co-sedimentation assays, and surface plasmon resonance spectroscopy. Interaction of CycR with Clr, and of CyaC with Clr requires the presence of cAMP and of ATP, respectively, whereas that of CyaC with CycR was independent of the nucleotides. CONCLUSION The data implicate a ternary CyaC×CycR×cAMP-Clr complex, functioning as a specific signaling cascade which is formed after activation of CyaC and synthesis of cAMP. cAMP-Clr is thought to work in complex with CycR to regulate a subset of genes of the cAMP-Clr regulon in S. meliloti.
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Affiliation(s)
- Robin Klein
- Institute of Molecular Physiology (imP), Microbiology and Biotechnology, Johannes Gutenberg University, Biocenter II, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
| | - Jannis Brehm
- Institute of Molecular Physiology (imP), Microbiology and Biotechnology, Johannes Gutenberg University, Biocenter II, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
| | - Juliane Wissig
- Institute of Molecular Physiology (imP), Microbiology and Biotechnology, Johannes Gutenberg University, Biocenter II, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
| | - Ralf Heermann
- Institute of Molecular Physiology (imP), Microbiology and Biotechnology, Johannes Gutenberg University, Biocenter II, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany.
| | - Gottfried Unden
- Institute of Molecular Physiology (imP), Microbiology and Biotechnology, Johannes Gutenberg University, Biocenter II, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany.
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Wu Y, Zhu X, Wang X, Lin Z, Reinfelder JR, Li F, Liu T. A New Electron Shuttling Pathway Mediated by Lipophilic Phenoxazine via the Interaction with Periplasmic and Inner Membrane Proteins of Shewanella oneidensis MR-1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2636-2646. [PMID: 36652548 DOI: 10.1021/acs.est.2c07862] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Although it has been established that electron mediators substantially promote extracellular electron transfer (EET), electron shuttling pathways are not fully understood. Here, a new electron shuttling pathway was found in the EET process by Shewanella oneidensis MR-1 with resazurin, a lipophilic electron mediator. With resazurin, the genes encoding outer-membrane cytochromes (mtrCBA and omcA) were downregulated. Although cytochrome deletion substantially reduced biocurrent generation to 1-12% of that of wild-type (WT) cells, the presence of resazurin restored biocurrent generation to 168 μA·cm-2 (ΔmtrA/omcA/mtrC), nearly equivalent to that of WT cells (194 μA·cm-2), indicating that resazurin-mediated electron transfer was not dependent on the Mtr pathway. Biocurrent generation by resazurin was much lower in ΔcymA and ΔmtrA/omcA/mtrC/fccA/cctA mutants (4 and 6 μA·cm-2) than in WT cells, indicating a key role of FccA, CctA, and CymA in this process. The effectiveness of resazurin in EET of Mtr cytochrome mutants is also supported by cyclic voltammetry, resazurin reduction kinetics, and in situ c-type cytochrome spectroscopy results. The findings demonstrated that low molecular weight, lipophilic electron acceptors, such as phenoxazine and phenazine, may facilitate electron transfer directly from periplasmic and inner membrane proteins, thus providing new insight into the roles of exogenous electron mediators in electron shuttling in natural and engineered biogeochemical systems.
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Affiliation(s)
- Yundang Wu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiao Zhu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xinxin Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
| | - Zhixin Lin
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - John R Reinfelder
- Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey 08901, United States
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
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Schultz JE. The evolutionary conservation of eukaryotic membrane-bound adenylyl cyclase isoforms. Front Pharmacol 2022; 13:1009797. [PMID: 36238545 PMCID: PMC9552081 DOI: 10.3389/fphar.2022.1009797] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/06/2022] [Indexed: 11/18/2022] Open
Abstract
The nine membrane-delimited eukaryotic adenylyl cyclases are pseudoheterodimers with an identical domain order of seven (nine) distinct subdomains. Bioinformatics show that the protein evolved from a monomeric bacterial progenitor by gene duplication and fusion probably in a primordial eukaryotic cell around 1.5 billion years ago. Over a timespan of about 1 billion years, the first fusion product diverged into nine highly distinct pseudoheterodimeric isoforms. The evolutionary diversification ended approximately 0.5 billion years ago because the present isoforms are found in the living fossil coelacanth, a fish. Except for the two catalytic domains, C1 and C2, the mAC isoforms are fully diverged. Yet, within each isoform a high extent of conservation of respective subdomains is found. This applies to the C- and N-termini, a long linker region between the protein halves (C1b), two short cyclase-transducing-elements (CTE) and notably to the two hexahelical membrane domains TM1 and TM2. Except for the membrane anchor all subdomains were previously implicated in regulatory modalities. The bioinformatic results unequivocally indicate that the membrane anchors must possess an important regulatory function specifically tailored for each mAC isoform.
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Quinones: More Than Electron Shuttles. Res Microbiol 2022; 173:103953. [DOI: 10.1016/j.resmic.2022.103953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/08/2022] [Accepted: 04/14/2022] [Indexed: 11/21/2022]
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Jiang D, Min Z, Leng J, Niu H, Chen Y, Liu D, Zhu C, Li M, Zhuang W, Ying H. Characterization of two halophilic adenylate cyclases from Thermobifida halotolerans and Haloactinopolyspora alba. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kouzuma A. Molecular mechanisms regulating the catabolic and electrochemical activities of Shewanella oneidensis MR-1. Biosci Biotechnol Biochem 2021; 85:1572-1581. [PMID: 33998649 DOI: 10.1093/bbb/zbab088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/17/2021] [Indexed: 11/14/2022]
Abstract
Electrochemically active bacteria (EAB) interact electrochemically with electrodes via extracellular electron transfer (EET) pathways. These bacteria have attracted significant attention due to their utility in environmental-friendly bioelectrochemical systems (BESs), including microbial fuel cells and electrofermentation systems. The electrochemical activity of EAB is dependent on their carbon catabolism and respiration; thus, understanding how these processes are regulated will provide insights into the development of a more efficient BES. The process of biofilm formation by EAB on BES electrodes is also important for electric current generation because it facilitates physical and electrochemical interactions between EAB cells and electrodes. This article summarizes the current knowledge on EET-related metabolic and cellular functions of a model EAB, Shewanella oneidensis MR-1, focusing specifically on regulatory systems for carbon catabolism, EET pathways, and biofilm formation. Based on recent developments, the author also discusses potential uses of engineered S. oneidensis strains for various biotechnological applications.
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Affiliation(s)
- Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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Finkbeiner M, Grischin J, Seth A, Schultz JE. In search of a function for the membrane anchors of class IIIa adenylate cyclases. Int J Med Microbiol 2019; 309:245-251. [PMID: 30954381 DOI: 10.1016/j.ijmm.2019.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/08/2019] [Accepted: 03/21/2019] [Indexed: 10/27/2022] Open
Abstract
Nine pseudoheterodimeric mammalian adenylate cyclases possess two dissimilar hexahelical membrane domains (TM1 and TM2), two dissimilar cyclase-transducing-elements (CTEs) and two complementary catalytic domains forming a catalytic dimer (often termed cyclase-homology-domain, CHD). Canonically, these cyclases are regulated by G-proteins which are released upon ligand activation of G-protein-coupled receptors. So far, a biochemical function of the membrane domains beyond anchoring has not been established. For almost 30 years, work in our laboratory was based on the hypothesis that these voluminous membrane domains possess an additional physiological, possibly regulatory function. Over the years, we have generated numerous artificial fusion proteins between the catalytic domains of various bacterial adenylate cyclases which are active as homodimers and the membrane receptor domains of known bacterial signaling proteins such as chemotaxis receptors and quorum-sensors which have known ligands. Here we summarize the current status of our experimental efforts. Taken together, the data allow the conclusion that the hexahelical mammalian membrane anchors as well as similar membrane anchors from bacterial adenylate cyclase congeners are orphan receptors. A search for as yet unknown ligands of membrane-delimited adenylate cyclases is now warranted.
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Affiliation(s)
| | - Julia Grischin
- Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
| | - Anubha Seth
- Pharmazeutisches Institut der Universität Tübingen, Tübingen, Germany
| | - Joachim E Schultz
- Pharmazeutisches Institut der Universität Tübingen, Tübingen, Germany.
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