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Pham C, Nasr MA, Skarina T, Di Leo R, Kwan DH, Martin VJJ, Stogios PJ, Mahadevan R, Savchenko A. Functional and structural characterization of an IclR family transcription factor for the development of dicarboxylic acid biosensors. FEBS J 2024. [PMID: 38696354 DOI: 10.1111/febs.17149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/15/2024] [Accepted: 04/17/2024] [Indexed: 05/04/2024]
Abstract
Prokaryotic transcription factors (TFs) regulate gene expression in response to small molecules, thus representing promising candidates as versatile small molecule-detecting biosensors valuable for synthetic biology applications. The engineering of such biosensors requires thorough in vitro and in vivo characterization of TF ligand response as well as detailed molecular structure information. In this work, we functionally and structurally characterize the Pca regulon regulatory protein (PcaR) transcription factor belonging to the IclR transcription factor family. Here, we present in vitro functional analysis of the ligand profile of PcaR and the construction of genetic circuits for the characterization of PcaR as an in vivo biosensor in the model eukaryote Saccharomyces cerevisiae. We report the crystal structures of PcaR in the apo state and in complex with one of its ligands, succinate, which suggests the mechanism of dicarboxylic acid recognition by this transcription factor. This work contributes key structural and functional insights enabling the engineering of PcaR for dicarboxylic acid biosensors, in addition to providing more insights into the IclR family of regulators.
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Affiliation(s)
- Chester Pham
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Mohamed A Nasr
- Centre for Applied Synthetic Biology, Concordia University, Montreal, Canada
- Department of Biology, Concordia University, Montreal, Canada
- PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Rosa Di Leo
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - David H Kwan
- Centre for Applied Synthetic Biology, Concordia University, Montreal, Canada
- Department of Biology, Concordia University, Montreal, Canada
- PROTEO, Quebec Network for Research on Protein Function, Structure, and Engineering, Canada
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Canada
| | - Vincent J J Martin
- Centre for Applied Synthetic Biology, Concordia University, Montreal, Canada
- Department of Biology, Concordia University, Montreal, Canada
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
- The Institute of Biomedical Engineering, University of Toronto, Canada
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Canada
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Akiyama T, Sasaki Y, Ito S, Yajima S. Structural basis of the conformational changes in Microbacterium hydrocarbonoxydans IclR transcription factor homolog due to ligand binding. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140644. [PMID: 33716191 DOI: 10.1016/j.bbapap.2021.140644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 11/26/2022]
Abstract
Microbacterium hydrocarbonoxydans has been isolated using an unnatural acylhydrazide compound as the sole carbon source. The compound is hydrolyzed by bacterial hydrazidase, and the gene expression of the enzyme is considered to be controlled by a transcription factor of the Isocitrate lyase Regulator (IclR) family, belonging to the one-component signaling systems. Recently, we reported the crystal structure of an unliganded IclR homolog from M. hydrocarbonoxydans, named putative 4-hydroxybenzoate response regulator (pHbrR), which has a unique homotetramer conformation. In this study, we report the crystal structure of pHbrR complexed with 4-hydroxybenzoic acid, the catalytic product of hydrazidase, at 2.0 Å resolution. pHbrR forms a homodimer with multimeric rearrangement in the unliganded state. Gel filtration column chromatography results suggested dimer-tetramer rearrangement. We observed conformational change in the loop region covering the ligand-binding site, and domain rearrangements in the monomer. This study reports the first liganded IclR family protein structure that demonstrates large structural rearrangements between liganded and unliganded proteins, which may represent a general model for IclRs.
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Affiliation(s)
- Tomonori Akiyama
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Yasuyuki Sasaki
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Shinsaku Ito
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Shunsuke Yajima
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan.
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Pardo I, Jha RK, Bermel RE, Bratti F, Gaddis M, McIntyre E, Michener W, Neidle EL, Dale T, Beckham GT, Johnson CW. Gene amplification, laboratory evolution, and biosensor screening reveal MucK as a terephthalic acid transporter in Acinetobacter baylyi ADP1. Metab Eng 2020; 62:260-274. [DOI: 10.1016/j.ymben.2020.09.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/11/2020] [Accepted: 09/19/2020] [Indexed: 12/19/2022]
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Oh KW, Kim K, Islam MM, Jung HW, Lim D, Lee JC, Shin M. Transcriptional Regulation of the Outer Membrane Protein A in Acinetobacter baumannii. Microorganisms 2020; 8:microorganisms8050706. [PMID: 32403355 PMCID: PMC7284552 DOI: 10.3390/microorganisms8050706] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/05/2020] [Accepted: 05/08/2020] [Indexed: 01/19/2023] Open
Abstract
Acinetobacter baumannii is known for its virulence in severely ill, hospitalized patients and for exhibiting multidrug resistance. A. baumannii infection treatment poses a serious problem in clinical environments. The outer membrane protein A (OmpA) of the Acinetobacter genus is involved in bacterial virulence. Regulatory factors of OmpA in the post-transcriptional stage have been previously identified. However, the regulatory factors that act before the transcriptional stage remain unclear. We investigated the A1S_0316 gene that encodes a putative transcription factor for OmpA expression in A. baumannii. A1S_0316 was purified and examined using size-exclusion chromatography, which revealed that it forms an oligomer. The binding affinity of A1S_0316 to the OmpA promoter region was also examined. We compared the binding affinity to the OmpA promotor region between A1S_0316 and the AbH-NS protein. A1S_0316 showed higher binding affinity to the OmpA promotor region than did H-NS. We examined the regulatory effect of these proteins on OmpA expression in A. baumannii using real-time qPCR and various in vitro tools. Our results indicated that A1S_0316 acts as an anti-repressor on the promotor region of the OmpA gene by inhibiting the binding of the AbH-NS protein. This study was the first demonstration of the transcriptional regulation of OmpA expression.
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Affiliation(s)
- Kyu-Wan Oh
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Korea; (K.-W.O.); (K.K.); (M.M.I.); (H.-W.J.); (J.C.L.)
| | - Kyeongmin Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Korea; (K.-W.O.); (K.K.); (M.M.I.); (H.-W.J.); (J.C.L.)
| | - Md. Maidul Islam
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Korea; (K.-W.O.); (K.K.); (M.M.I.); (H.-W.J.); (J.C.L.)
| | - Hye-Won Jung
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Korea; (K.-W.O.); (K.K.); (M.M.I.); (H.-W.J.); (J.C.L.)
| | - Daejin Lim
- Department of Microbiology, School of Medicine, Chonnam National University, Gwangju 61468, Korea;
| | - Je Chul Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Korea; (K.-W.O.); (K.K.); (M.M.I.); (H.-W.J.); (J.C.L.)
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 41944, Korea; (K.-W.O.); (K.K.); (M.M.I.); (H.-W.J.); (J.C.L.)
- Correspondence: ; Tel.: +82-53-420-4841
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