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Parejo S, Cabrera JJ, Jiménez-Leiva A, Tomás-Gallardo L, Bedmar EJ, Gates AJ, Mesa S. Fine-Tuning Modulation of Oxidation-Mediated Posttranslational Control of Bradyrhizobium diazoefficiens FixK 2 Transcription Factor. Int J Mol Sci 2022; 23:5117. [PMID: 35563511 PMCID: PMC9104804 DOI: 10.3390/ijms23095117] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/22/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
FixK2 is a CRP/FNR-type transcription factor that plays a central role in a sophisticated regulatory network for the anoxic, microoxic and symbiotic lifestyles of the soybean endosymbiont Bradyrhizobium diazoefficiens. Aside from the balanced expression of the fixK2 gene under microoxic conditions (induced by the two-component regulatory system FixLJ and negatively auto-repressed), FixK2 activity is posttranslationally controlled by proteolysis, and by the oxidation of a singular cysteine residue (C183) near its DNA-binding domain. To simulate the permanent oxidation of FixK2, we replaced C183 for aspartic acid. Purified C183D FixK2 protein showed both low DNA binding and in vitro transcriptional activation from the promoter of the fixNOQP operon, required for respiration under symbiosis. However, in a B. diazoefficiens strain coding for C183D FixK2, expression of a fixNOQP'-'lacZ fusion was similar to that in the wild type, when both strains were grown microoxically. The C183D FixK2 encoding strain also showed a wild-type phenotype in symbiosis with soybeans, and increased fixK2 gene expression levels and FixK2 protein abundance in cells. These two latter observations, together with the global transcriptional profile of the microoxically cultured C183D FixK2 encoding strain, suggest the existence of a finely tuned regulatory strategy to counterbalance the oxidation-mediated inactivation of FixK2 in vivo.
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Affiliation(s)
- Sergio Parejo
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Juan J. Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Andrea Jiménez-Leiva
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Laura Tomás-Gallardo
- Proteomics and Biochemistry Unit, Andalusian Centre for Developmental Biology, CSIC-Pablo de Olavide University, 41013 Seville, Spain;
| | - Eulogio J. Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Andrew J. Gates
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK;
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
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Cabrera JJ, Jiménez-Leiva A, Tomás-Gallardo L, Parejo S, Casado S, Torres MJ, Bedmar EJ, Delgado MJ, Mesa S. Dissection of FixK 2 protein-DNA interaction unveils new insights into Bradyrhizobium diazoefficiens lifestyles control. Environ Microbiol 2021; 23:6194-6209. [PMID: 34227211 DOI: 10.1111/1462-2920.15661] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 11/28/2022]
Abstract
The FixK2 protein plays a pivotal role in a complex regulatory network, which controls genes for microoxic, denitrifying, and symbiotic nitrogen-fixing lifestyles in Bradyrhizobium diazoefficiens. Among the microoxic-responsive FixK2 -activated genes are the fixNOQP operon, indispensable for respiration in symbiosis, and the nnrR regulatory gene needed for the nitric-oxide dependent induction of the norCBQD genes encoding the denitrifying nitric oxide reductase. FixK2 is a CRP/FNR-type transcription factor, which recognizes a 14 bp-palindrome (FixK2 box) at the regulated promoters through three residues (L195, E196, and R200) within a C-terminal helix-turn-helix motif. Here, we mapped the determinants for discriminatory FixK2 -mediated regulation. While R200 was essential for DNA binding and activity of FixK2 , L195 was involved in protein-DNA complex stability. Mutation at positions 1, 3, or 11 in the genuine FixK2 box at the fixNOQP promoter impaired transcription activation by FixK2 , which was residual when a second mutation affecting the box palindromy was introduced. The substitution of nucleotide 11 within the NnrR box at the norCBQD promoter allowed FixK2 -mediated activation in response to microoxia. Thus, position 11 within the FixK2 /NnrR boxes constitutes a key element that changes FixK2 targets specificity, and consequently, it might modulate B. diazoefficiens lifestyle as nitrogen fixer or as denitrifier.
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Affiliation(s)
- Juan J Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - Andrea Jiménez-Leiva
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - Laura Tomás-Gallardo
- Proteomics and Biochemistry Unit, Andalusian Centre for Developmental Biology, CSIC-Junta de Andalucía-Pablo de Olavide University, Seville, 41013, Spain
| | - Sergio Parejo
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - Sara Casado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - María J Torres
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - Eulogio J Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - María J Delgado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Granada, 18008, Spain
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Salas A, Cabrera JJ, Jiménez-Leiva A, Mesa S, Bedmar EJ, Richardson DJ, Gates AJ, Delgado MJ. Bacterial nitric oxide metabolism: Recent insights in rhizobia. Adv Microb Physiol 2021; 78:259-315. [PMID: 34147187 DOI: 10.1016/bs.ampbs.2021.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nitric oxide (NO) is a reactive gaseous molecule that has several functions in biological systems depending on its concentration. At low concentrations, NO acts as a signaling molecule, while at high concentrations, it becomes very toxic due to its ability to react with multiple cellular targets. Soil bacteria, commonly known as rhizobia, have the capacity to establish a N2-fixing symbiosis with legumes inducing the formation of nodules in their roots. Several reports have shown NO production in the nodules where this gas acts either as a signaling molecule which regulates gene expression, or as a potent inhibitor of nitrogenase and other plant and bacteria enzymes. A better understanding of the sinks and sources of NO in rhizobia is essential to protect symbiotic nitrogen fixation from nitrosative stress. In nodules, both the plant and the microsymbiont contribute to the production of NO. From the bacterial perspective, the main source of NO reported in rhizobia is the denitrification pathway that varies significantly depending on the species. In addition to denitrification, nitrate assimilation is emerging as a new source of NO in rhizobia. To control NO accumulation in the nodules, in addition to plant haemoglobins, bacteroids also contribute to NO detoxification through the expression of a NorBC-type nitric oxide reductase as well as rhizobial haemoglobins. In the present review, updated knowledge about the NO metabolism in legume-associated endosymbiotic bacteria is summarized.
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Affiliation(s)
- Ana Salas
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juan J Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain; School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Andrea Jiménez-Leiva
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Eulogio J Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - David J Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Andrew J Gates
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - María J Delgado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.
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Abstract
Rhizobia are a phylogenetically diverse group of soil bacteria that engage in mutualistic interactions with legume plants. Although specifics of the symbioses differ between strains and plants, all symbioses ultimately result in the formation of specialized root nodule organs which host the nitrogen-fixing microsymbionts called bacteroids. Inside nodules, bacteroids encounter unique conditions that necessitate global reprogramming of physiological processes and rerouting of their metabolism. Decades of research have addressed these questions using genetics, omics approaches, and more recently computational modelling. Here we discuss the common adaptations of rhizobia to the nodule environment that define the core principles of bacteroid functioning. All bacteroids are growth-arrested and perform energy-intensive nitrogen fixation fueled by plant-provided C4-dicarboxylates at nanomolar oxygen levels. At the same time, bacteroids are subject to host control and sanctioning that ultimately determine their fitness and have fundamental importance for the evolution of a stable mutualistic relationship.
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Feeley BE, Bhardwaj V, McLaughlin PT, Diggs S, Blaha GM, Higgs PI. An amino-terminal threonine/serine motif is necessary for activity of the Crp/Fnr homolog, MrpC and for Myxococcus xanthus developmental robustness. Mol Microbiol 2019; 112:1531-1551. [PMID: 31449700 DOI: 10.1111/mmi.14378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2019] [Indexed: 11/30/2022]
Abstract
The Crp/Fnr family of transcriptional regulators play central roles in transcriptional control of diverse physiological responses, and are activated by a surprising diversity of mechanisms. MrpC is a Crp/Fnr homolog that controls the Myxococcus xanthus developmental program. A long-standing model proposed that MrpC activity is controlled by the Pkn8/Pkn14 serine/threonine kinase cascade, which phosphorylates MrpC on threonine residue(s) located in its extreme amino-terminus. In this study, we demonstrate that a stretch of consecutive threonine and serine residues, T21 T22 S23 S24, is necessary for MrpC activity by promoting efficient DNA binding. Mass spectrometry analysis indicated the TTSS motif is not directly phosphorylated by Pkn14 in vitro but is necessary for efficient Pkn14-dependent phosphorylation on several residues in the remainder of the protein. In an important correction to a long-standing model, we show Pkn8 and Pkn14 kinase activities do not play obvious roles in controlling MrpC activity in wild-type M. xanthus under laboratory conditions. Instead, we propose Pkn14 modulates MrpC DNA binding in response to unknown environmental conditions. Interestingly, substitutions in the TTSS motif caused developmental defects that varied between biological replicates, revealing that MrpC plays a role in promoting a robust developmental phenotype.
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Affiliation(s)
- Brooke E Feeley
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Vidhi Bhardwaj
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Hesse, Germany
| | | | - Stephen Diggs
- Department of Biochemistry, University of California, Riverside, Riverside, CA, USA
| | - Gregor M Blaha
- Department of Biochemistry, University of California, Riverside, Riverside, CA, USA
| | - Penelope I Higgs
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
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Fernández N, Cabrera JJ, Varadarajan AR, Lutz S, Ledermann R, Roschitzki B, Eberl L, Bedmar EJ, Fischer HM, Pessi G, Ahrens CH, Mesa S. An Integrated Systems Approach Unveils New Aspects of Microoxia-Mediated Regulation in Bradyrhizobium diazoefficiens. Front Microbiol 2019; 10:924. [PMID: 31134003 PMCID: PMC6515984 DOI: 10.3389/fmicb.2019.00924] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/11/2019] [Indexed: 01/31/2023] Open
Abstract
The adaptation of rhizobia from the free-living state in soil to the endosymbiotic state comprises several physiological changes in order to cope with the extremely low oxygen availability (microoxia) within nodules. To uncover cellular functions required for bacterial adaptation to microoxia directly at the protein level, we applied a systems biology approach on the key rhizobial model and soybean endosymbiont Bradyrhizobium diazoefficiens USDA 110 (formerly B. japonicum USDA 110). As a first step, the complete genome of B. diazoefficiens 110spc4, the model strain used in most prior functional genomics studies, was sequenced revealing a deletion of a ~202 kb fragment harboring 223 genes and several additional differences, compared to strain USDA 110. Importantly, the deletion strain showed no significantly different phenotype during symbiosis with several host plants, reinforcing the value of previous OMICS studies. We next performed shotgun proteomics and detected 2,900 and 2,826 proteins in oxically and microoxically grown cells, respectively, largely expanding our knowledge about the inventory of rhizobial proteins expressed in microoxia. A set of 62 proteins was significantly induced under microoxic conditions, including the two nitrogenase subunits NifDK, the nitrogenase reductase NifH, and several subunits of the high-affinity terminal cbb3 oxidase (FixNOQP) required for bacterial respiration inside nodules. Integration with the previously defined microoxia-induced transcriptome uncovered a set of 639 genes or proteins uniquely expressed in microoxia. Finally, besides providing proteogenomic evidence for novelties, we also identified proteins with a regulation similar to that of FixK2: transcript levels of these protein-coding genes were significantly induced, while the corresponding protein abundance remained unchanged or was down-regulated. This suggested that, apart from fixK2, additional B. diazoefficiens genes might be under microoxia-specific post-transcriptional control. This hypothesis was indeed confirmed for several targets (HemA, HemB, and ClpA) by immunoblot analysis.
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Affiliation(s)
- Noemí Fernández
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juan J Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Adithi R Varadarajan
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics and Swiss Institute of Bioinformatics, Wädenswil, Switzerland.,Department of Health Sciences and Technology, Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Stefanie Lutz
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics and Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | | | - Bernd Roschitzki
- Functional Genomics Center Zurich, ETH & UZH Zurich, Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Eulogio J Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | | | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Christian H Ahrens
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics and Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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Yeom J, Wayne KJ, Groisman EA. Sequestration from Protease Adaptor Confers Differential Stability to Protease Substrate. Mol Cell 2017; 66:234-246.e5. [PMID: 28431231 DOI: 10.1016/j.molcel.2017.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/23/2017] [Accepted: 03/14/2017] [Indexed: 12/24/2022]
Abstract
According to the N-end rule, the N-terminal residue of a protein determines its stability. In bacteria, the adaptor ClpS mediates proteolysis by delivering substrates bearing specific N-terminal residues to the protease ClpAP. We now report that the Salmonella adaptor ClpS binds to the N terminus of the regulatory protein PhoP, resulting in PhoP degradation by ClpAP. We establish that the PhoP-activated protein MgtC protects PhoP from degradation by outcompeting ClpS for binding to PhoP. MgtC appears to act exclusively on PhoP, as it did not alter the stability of a different ClpS-dependent ClpAP substrate. Removal of five N-terminal residues rendered PhoP stability independent of both the clpS and mgtC genes. By preserving PhoP protein levels, MgtC enables normal temporal transcription of PhoP-activated genes. The identified mechanism provides a simple means to spare specific substrates from an adaptor-dependent protease.
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Affiliation(s)
- Jinki Yeom
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
| | - Kyle J Wayne
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
| | - Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA; Yale Microbial Sciences Institute, P.O. Box 27389, West Haven, CT 06516, USA.
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Hong EJ, Park JS, Kim Y, Lee HS. Role of Corynebacterium glutamicum sprA encoding a serine protease in glxR-mediated global gene regulation. PLoS One 2014; 9:e93587. [PMID: 24691519 PMCID: PMC3972247 DOI: 10.1371/journal.pone.0093587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 03/05/2014] [Indexed: 11/19/2022] Open
Abstract
The global regulator glxR of Corynebacterium glutamicum is involved in many cellular activities. Considering its role, the GlxR protein likely interacts with other proteins to obtain, maintain, and control its activity. To isolate proteins interacting with GlxR, we used a two-hybrid system with GlxR as the bait. Subsequently, the partner, a subtilisin-like serine protease, was isolated from a C. glutamicum genomic library. Unlike glxR, which showed constitutive expression, the expression of sprA, encoding a serine protease, was maximal in the log phase. Purified His6-SprA protein underwent self-proteolysis and proteolyzed purified GlxR. The proteolytic action of SprA on GlxR was not observed in the presence of cyclic adenosine monophosphate, which modulates GlxR activity. The C. glutamicum sprA deletion mutant (ΔsprA) and sprA-overexpressing (P180-sprA) strains showed reduced growth. The activity of isocitrate dehydrogenase (a tricarboxylic acid cycle enzyme) in these strains decreased to 30–50% of that in the wild-type strain. In the P180-sprA strain, proteins involved in diverse cellular functions such as energy and carbon metabolism (NCgl2809), nitrogen metabolism (NCgl0049), methylation reactions (NCgl0719), and peptidoglycan biosynthesis (NCgl1267), as well as stress, starvation, and survival (NCgl0938) were affected and showed decreased transcription. Taken together, these data suggest that SprA, as a serine protease, performs a novel regulatory role not only in glxR-mediated gene expression but also in other areas of cell physiology. In addition, the tight control of SprA and GlxR availability may indicate their importance in global gene regulation.
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Affiliation(s)
- Eun-Ji Hong
- Department of Biotechnology and Bioinformatics, Korea University, Sejong-ro, Sejong-si, Korea
| | - Joon-Song Park
- Department of Biotechnology and Bioinformatics, Korea University, Sejong-ro, Sejong-si, Korea
| | - Younhee Kim
- Department of Oriental Medicine, Semyung University, Checheon, Chungbuk, Korea
| | - Heung-Shick Lee
- Department of Biotechnology and Bioinformatics, Korea University, Sejong-ro, Sejong-si, Korea
- * E-mail:
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Bonnet M, Kurz M, Mesa S, Briand C, Hennecke H, Grütter MG. The structure of Bradyrhizobium japonicum transcription factor FixK2 unveils sites of DNA binding and oxidation. J Biol Chem 2013; 288:14238-14246. [PMID: 23546876 DOI: 10.1074/jbc.m113.465484] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
FixK2 is a regulatory protein that activates a large number of genes for the anoxic and microoxic, endosymbiotic, and nitrogen-fixing life styles of the α-proteobacterium Bradyrhizobium japonicum. FixK2 belongs to the cAMP receptor protein (CRP) superfamily. Although most CRP family members are coregulated by effector molecules, the activity of FixK2 is negatively controlled by oxidation of its single cysteine (Cys-183) located next to the DNA-binding domain and possibly also by proteolysis. Here, we report the three-dimensional x-ray structure of FixK2, a representative of the FixK subgroup of the CRP superfamily. Crystallization succeeded only when (i) an oxidation- and protease-insensitive protein variant (FixK2(C183S)-His6) was used in which Cys-183 was replaced with serine and the C terminus was fused with a hexahistidine tag and (ii) this protein was allowed to form a complex with a 30-mer double-stranded target DNA. The structure of the FixK2-DNA complex was solved at a resolution of 1.77 Å, at which the protein formed a homodimer. The precise protein-DNA contacts were identified, which led to an affirmation of the canonical target sequence, the so-called FixK2 box. The C terminus is surface-exposed, which might explain its sensitivity to specific cleavage and degradation. The oxidation-sensitive Cys-183 is also surface-exposed and in close proximity to DNA. Therefore, we propose a mechanism whereby the oxo acids generated after oxidation of the cysteine thiol cause an electrostatic repulsion, thus preventing specific DNA binding.
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Affiliation(s)
- Mariette Bonnet
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Mareike Kurz
- Department of Biochemistry, University of Zürich, CH-8057 Zürich, Switzerland
| | - Socorro Mesa
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Christophe Briand
- Department of Biochemistry, University of Zürich, CH-8057 Zürich, Switzerland
| | - Hauke Hennecke
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Markus G Grütter
- Department of Biochemistry, University of Zürich, CH-8057 Zürich, Switzerland.
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