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Filipek J, Chalaskiewicz K, Kosmider A, Nielipinski M, Michalak A, Bednarkiewicz M, Goslawski-Zeligowski M, Prucnal F, Sekula B, Pietrzyk-Brzezinska AJ. Comprehensive structural overview of the C-terminal ligand-binding domains of the TetR family regulators. J Struct Biol 2024; 216:108071. [PMID: 38401830 DOI: 10.1016/j.jsb.2024.108071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 02/26/2024]
Abstract
TetR family regulators (TFRs) represent a large group of one-component bacterial signal transduction systems which recognize environmental signals, like the presence of antibiotics or other bactericidal compounds, and trigger the cell response by regulating the expression of genes that secure bacterial survival in harsh environmental conditions. TFRs act as homodimers, each protomer is composed of a conserved DNA-binding N-terminal domain (NTD) and a variable ligand-binding C-terminal domain (CTD). Currently, there are about 500 structures of TFRs available in the Protein Data Bank and one-fourth of them represent the structures of TFR-ligand complexes. In this review, we summarized information on the ligands interacting with TFRs and based on structural data, we compared the CTDs of the TFR family members, as well as their ligand-binding cavities. Additionally, we divided the whole TFR family, including more than half of a million sequences, into subfamilies according to calculated multiple sequence alignment and phylogenetic tree. We also highlighted structural elements characteristic of some of the subfamilies. The presented comprehensive overview of the TFR CTDs provides good bases and future directions for further studies on TFRs that are not only important targets for battling multidrug resistance but also good candidates for many biotechnological approaches, like TFR-based biosensors.
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Affiliation(s)
- Jakub Filipek
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland
| | - Katarzyna Chalaskiewicz
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland; Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Stefanowskiego 2/22, Lodz 90-537, Poland
| | - Aleksandra Kosmider
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland
| | - Maciej Nielipinski
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland; Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Stefanowskiego 2/22, Lodz 90-537, Poland
| | - Agnieszka Michalak
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland
| | - Maria Bednarkiewicz
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland
| | - Mieszko Goslawski-Zeligowski
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland
| | - Filip Prucnal
- Biotechnology Students Association Ferment, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Wolczanska 171/173, 90-530 Lodz, Poland
| | - Bartosz Sekula
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Stefanowskiego 2/22, Lodz 90-537, Poland
| | - Agnieszka J Pietrzyk-Brzezinska
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Stefanowskiego 2/22, Lodz 90-537, Poland.
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2
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Chen X, Varghese S, Zhang Z, Du J, Ruan B, Baell JB, Liu X. Drug discovery and optimization based on the co-crystal structure of natural product with target. Eur J Med Chem 2024; 266:116126. [PMID: 38232464 DOI: 10.1016/j.ejmech.2024.116126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 01/19/2024]
Abstract
Due to their structural diversities and prevalent biological activities, natural products (NPs) are momentous resources for drug discovery. Although NPs have a wide range of biological activities, many exhibit structural complexity that leads to synthetic difficulties, which combines with inefficient biological activity, toxicity, and unfavorable pharmacokinetic characteristics and ultimately imparts poor safety and efficacy outcomes. Progress in crystallization and computational techniques allow crystallography to have a seasonable influences on drug discovery. By co-crystallizing with proteins, therapeutic targets of NPs in specific diseases can be identified. By analyzing the co-crystal information, the structure-activity relationships (SARs) of NPs targeting specific proteins can be grasped. Under the guidance of co-crystal information, directional structural modification and simplification are powerful strategies for overcoming limitations of NPs, improving the success rate of NP-based drug discovery, and obtaining NP-based drugs with high selectivity, low toxicity and favorable pharmacokinetic characteristics. Here, we review the co-crystal information of a selection of NPs, focusing on the SARs of NPs reflected by co-crystal information and the modification and simplification strategies of NPs, and discuss how to apply co-crystal information in the optimization of NP-based lead compound.
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Affiliation(s)
- Xing Chen
- School of Pharmacy, Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, 230032, PR China; School of Public Health, Key Laboratory of Population Health Across Life Cycle, Anhui Medical University, Hefei, 230032, PR China.
| | - Swapna Varghese
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria, 3052, Australia.
| | - Zhaoyan Zhang
- School of Pharmacy, Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, 230032, PR China.
| | - Juncheng Du
- School of Pharmacy, Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, 230032, PR China.
| | - Banfeng Ruan
- Key Lab of Biofabrication of Anhui Higher Education, Hefei University, Hefei, 230601, PR China.
| | - Jonathan B Baell
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria, 3052, Australia.
| | - Xinhua Liu
- School of Pharmacy, Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, 230032, PR China.
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3
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Odžak R, Crnčević D, Sabljić A, Krce L, Paladin A, Primožič I, Šprung M. Further Study of the Polar Group's Influence on the Antibacterial Activity of the 3-Substituted Quinuclidine Salts with Long Alkyl Chains. Antibiotics (Basel) 2023; 12:1231. [PMID: 37627651 PMCID: PMC10451673 DOI: 10.3390/antibiotics12081231] [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: 06/15/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
Quaternary ammonium compounds (QACs) are among the most potent antimicrobial agents increasingly used by humans as disinfectants, antiseptics, surfactants, and biological dyes. As reports of bacterial co- and cross-resistance to QACs and their toxicity have emerged in recent years, new attempts are being made to develop soft QACs by introducing hydrolyzable groups that allow their controlled degradation. However, the development of such compounds has been hindered by the structural features that affect the bioactivity of QACs, one of them being polarity of the substituent near the quaternary center. To further investigate the influence of the polar group on the bioactivity of QACs, we synthesized 3-aminoquinuclidine salts for comparison with their structural analogues, 3-acetamidoquinuclidines. We found that the less polar amino-substituted compounds exhibited improved antibacterial activity over their more polar amide analogues. In addition to their better minimum inhibitory concentrations, the candidates were excellent at suppressing Staphylococcus aureus biofilm formation and killing bacteria almost immediately, as shown by the flow cytometry measurements. In addition, two candidates, namely QNH2-C14 and QNH2-C16, effectively suppressed bacterial growth even at concentrations below the MIC. QNH2-C14 was particularly effective at subinhibitory concentrations, inhibiting bacterial growth for up to 6 h. In addition, we found that the compounds targeted the bacterial membrane, leading to its perforation and subsequent cell death. Their low toxicity to human cells and low potential to develop bacterial resistance suggest that these compounds could serve as a basis for the development of new QACs.
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Affiliation(s)
- Renata Odžak
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
| | - Doris Crnčević
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
- Doctoral Study of Biophysics, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia
| | - Antonio Sabljić
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
- Doctoral Study of Biophysics, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia
| | - Lucija Krce
- Department of Physics, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia;
| | - Antonela Paladin
- Department of Biology, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia;
| | - Ines Primožič
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia;
| | - Matilda Šprung
- Department of Chemistry, Faculty of Science, University of Split, R. Bošković 33, 21000 Split, Croatia; (R.O.); (D.C.); (A.S.)
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4
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Werner N, Werten S, Hoppen J, Palm GJ, Göttfert M, Hinrichs W. The induction mechanism of the flavonoid-responsive regulator FrrA. FEBS J 2022; 289:507-518. [PMID: 34314575 DOI: 10.1111/febs.16141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 07/13/2021] [Accepted: 07/26/2021] [Indexed: 11/29/2022]
Abstract
Bradyrhizobium diazoefficiens, a bacterial symbiont of soybean and other leguminous plants, enters a nodulation-promoting genetic programme in the presence of host-produced flavonoids and related signalling compounds. Here, we describe the crystal structure of an isoflavonoid-responsive regulator (FrrA) from Bradyrhizobium, as well as cocrystal structures with inducing and noninducing ligands (genistein and naringenin, respectively). The structures reveal a TetR-like fold whose DNA-binding domain is capable of adopting a range of orientations. A single molecule of either genistein or naringenin is asymmetrically bound in a central cavity of the FrrA homodimer, mainly via C-H contacts to the π-system of the ligands. Strikingly, however, the interaction does not provoke any conformational changes in the repressor. Both the flexible positioning of the DNA-binding domain and the absence of structural change upon ligand binding are corroborated by small-angle X-ray scattering (SAXS) experiments in solution. Together with a model of the promoter-bound state of FrrA our results suggest that inducers act as a wedge, preventing the DNA-binding domains from moving close enough together to interact with successive positions of the major groove of the palindromic operator.
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Affiliation(s)
- Nadine Werner
- Institute for Biochemistry, Department Molecular Structural Biology, University of Greifswald, Germany
| | - Sebastiaan Werten
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Austria
| | - Jens Hoppen
- Institute for Biochemistry, Department Molecular Structural Biology, University of Greifswald, Germany
| | - Gottfried J Palm
- Institute for Biochemistry, Department Molecular Structural Biology, University of Greifswald, Germany
| | - Michael Göttfert
- Institute of Genetics, Dresden University of Technology, Germany
| | - Winfried Hinrichs
- Institute for Biochemistry, Department Molecular Structural Biology, University of Greifswald, Germany
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5
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Pietrzyk-Brzezinska AJ, Cociurovscaia A. Structures of the TetR-like transcription regulator RcdA alone and in complexes with ligands. Proteins 2021; 90:33-44. [PMID: 34288132 DOI: 10.1002/prot.26183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/20/2021] [Accepted: 07/11/2021] [Indexed: 01/25/2023]
Abstract
RcdA is a helix-turn-helix (HTH) transcriptional regulator belonging to the TetR family. The protein regulates the transcription of curlin subunit gene D, the master regulator of biofilm formation. Moreover, it was predicted that it might be involved in the regulation of up to 27 different genes. However, an effector of RcdA and the environmental conditions which trigger RcdA action remain unknown. Herein, we report the first crystal structures of RcdA in complexes with ligands, trimethylamine N-oxide (TMAO) and tris(hydroxymethyl)aminomethane (Tris), which might serve as RcdA effectors. Based on these structures, the ligand-binding pocket of RcdA was characterized in detail. The conservation of the amino acid residues forming the ligand-binding cavity was analyzed and the comprehensive search for RcdA structural homologs was performed. This analysis indicated that RcdA is structurally similar to multidrug-binding TetR family members, however, its ligand-binding cavity differs significantly from the pockets of its structural homologs. The interaction of RcdA with TMAO and Tris indicates that the protein might be involved in alkaline stress response.
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Affiliation(s)
- Agnieszka J Pietrzyk-Brzezinska
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Lodz, Poland
| | - Anna Cociurovscaia
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Lodz, Poland
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6
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Henderson PJF, Maher C, Elbourne LDH, Eijkelkamp BA, Paulsen IT, Hassan KA. Physiological Functions of Bacterial "Multidrug" Efflux Pumps. Chem Rev 2021; 121:5417-5478. [PMID: 33761243 DOI: 10.1021/acs.chemrev.0c01226] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial multidrug efflux pumps have come to prominence in human and veterinary pathogenesis because they help bacteria protect themselves against the antimicrobials used to overcome their infections. However, it is increasingly realized that many, probably most, such pumps have physiological roles that are distinct from protection of bacteria against antimicrobials administered by humans. Here we undertake a broad survey of the proteins involved, allied to detailed examples of their evolution, energetics, structures, chemical recognition, and molecular mechanisms, together with the experimental strategies that enable rapid and economical progress in understanding their true physiological roles. Once these roles are established, the knowledge can be harnessed to design more effective drugs, improve existing microbial production of drugs for clinical practice and of feedstocks for commercial exploitation, and even develop more sustainable biological processes that avoid, for example, utilization of petroleum.
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Affiliation(s)
- Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Claire Maher
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia
| | - Liam D H Elbourne
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia, Australia
| | - Ian T Paulsen
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Karl A Hassan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
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7
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Bailly C. Medicinal applications and molecular targets of dequalinium chloride. Biochem Pharmacol 2021; 186:114467. [PMID: 33577890 DOI: 10.1016/j.bcp.2021.114467] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 12/23/2022]
Abstract
For more than 60 years dequalinium chloride (DQ) has been used as anti-infective drug, mainly to treat local infections. It is a standard drug to treat bacterial vaginosis and an active ingredient of sore-throat lozenges. As a lipophilic bis-quaternary ammonium molecule, the drug displays membrane effects and selectively targets mitochondria to deplete DNA and to block energy production in cells. But beyond its mitochondriotropic property, DQ can interfere with the correct functioning of diverse proteins. A dozen of DQ protein targets have been identified and their implication in the antibacterial, antiviral, antifungal, antiparasitic and anticancer properties of the drug is discussed here. The anticancer effects of DQ combine a mitochondrial action, a selective inhibition of kinases (PKC-α/β, Cdc7/Dbf4), and a modulation of Ca2+-activated K+ channels. At the bacterial level, DQ interacts with different multidrug transporters (QacR, AcrB, EmrE) and with the transcriptional regulator RamR. Other proteins implicated in the antiviral (MPER domain of gp41 HIV-1) and antiparasitic (chitinase A from Vibrio harveyi) activities have been identified. DQ also targets α -synuclein oligomers to restrict protofibrils formation implicated in some neurodegenerative disorders. In addition, DQ is a typical bolaamphiphile molecule, well suited to form liposomes and nanoparticules useful for drug entrapment and delivery (DQAsomes and others). Altogether, the review highlights the many pharmacological properties and therapeutic benefits of this old 'multi-talented' drug, which may be exploited further. Its multiple sites of actions in cells should be kept in mind when using DQ in experimental research.
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8
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Optimization of a Noncanonical Anti-infective: Interrogation of the Target Binding Pocket for a Small-Molecule Inhibitor of Escherichia coli Polysaccharide Capsule Expression. Antimicrob Agents Chemother 2020; 65:AAC.01208-20. [PMID: 33077659 DOI: 10.1128/aac.01208-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/13/2020] [Indexed: 11/20/2022] Open
Abstract
We previously identified a small-molecule inhibitor of capsule biogenesis (designated DU011) and identified its target as MprA, a MarR family transcriptional repressor of multidrug efflux pumps. Unlike other proposed MprA ligands, such as salicylate and 2,4-dinitrophenol (DNP), DU011 does not alter Escherichia coli antibiotic resistance and has significantly enhanced inhibition of capsule expression. We hypothesized that the potency and the unique action of DU011 are due to novel interactions with the MprA binding pocket and the conformation assumed by MprA upon binding DU011 relative to other ligands. To understand the dynamics of MprA-DU011 interaction, we performed hydrogen-deuterium exchange mass spectrometry (HDX-MS); this suggested that four peptide regions undergo conformational changes upon binding DU011. We conducted isothermal calorimetric titration (ITC) to quantitatively characterize MprA binding to DU011 and canonical ligands and observed a distinct two-site binding isotherm associated with the binding reaction of MprA to DU011; however, salicylate and DNP showed a one-site binding isotherm with lower affinity. To elucidate the binding pocket(s) of MprA, we selected single point mutants of MprA that included mutated residues predicted to be within the putative binding pocket (Q51A, F58A, and E65D) as well as on or near the DNA-binding domain (L81A, S83T, and T86A). Our ITC studies suggest that two of the tested MprA mutants had lower affinity for DU011: Q51A and F58A. In addition to elucidating the MprA binding pocket for DU011, we studied the binding of these mutants to salicylate and DNP to reveal the binding pockets of these canonical ligands.
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9
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Gutiérrez de Souza C, Bersellini M, Roelfes G. Artificial Metalloenzymes based on TetR Proteins and Cu(II) for Enantioselective Friedel-Crafts Alkylation Reactions. ChemCatChem 2020; 12:3190-3194. [PMID: 32612714 PMCID: PMC7319431 DOI: 10.1002/cctc.202000245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/31/2020] [Indexed: 12/16/2022]
Abstract
The supramolecular approach is among the most convenient methodologies for creating artificial metalloenzymes (ArMs). Usually this approach involves the binding of a transition metal ion complex to a biomolecular scaffold via its ligand, which also modulates the catalytic properties of the metal ion. Herein, we report ArMs based on the proteins CgmR, RamR and QacR from the TetR family of multidrug resistance regulators (MDRs) and Cu2+ ions, assembled without the need of a ligand. These ArMs catalyze the enantioselective vinylogous Friedel-Crafts alkylation reaction with up to 75 % ee. Competition experiments with ethidium and rhodamine 6G confirm that the reactions occur in the chiral environment of the hydrophobic pocket. It is proposed that the Cu2+-substrate complex is bound via a combination of electrostatic and π-stacking interactions provided by the second coordination sphere. This approach constitutes a fast and straightforward way to assemble metalloenzymes and may facilitate future optimization of the protein scaffolds via mutagenesis or directed evolution approaches.
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Affiliation(s)
- Cora Gutiérrez de Souza
- Stratingh Institute for ChemistryUniversity of Groningen Nijenborgh49747AG GroningenThe Netherlands
| | - Manuela Bersellini
- Stratingh Institute for ChemistryUniversity of Groningen Nijenborgh49747AG GroningenThe Netherlands
| | - Gerard Roelfes
- Stratingh Institute for ChemistryUniversity of Groningen Nijenborgh49747AG GroningenThe Netherlands
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10
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Dimas RP, Jordan BR, Jiang XL, Martini C, Glavy JS, Patterson DP, Morcos F, Chan CTY. Engineering DNA recognition and allosteric response properties of TetR family proteins by using a module-swapping strategy. Nucleic Acids Res 2019; 47:8913-8925. [PMID: 31392336 PMCID: PMC6895282 DOI: 10.1093/nar/gkz666] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 12/11/2022] Open
Abstract
The development of synthetic biological systems requires modular biomolecular components to flexibly alter response pathways. In previous studies, we have established a module-swapping design principle to engineer allosteric response and DNA recognition properties among regulators in the LacI family, in which the engineered regulators served as effective components for implementing new cellular behavior. Here we introduced this protein engineering strategy to two regulators in the TetR family: TetR (UniProt Accession ID: P04483) and MphR (Q9EVJ6). The TetR DNA-binding module and the MphR ligand-binding module were used to create the TetR-MphR. This resulting hybrid regulator possesses DNA-binding properties of TetR and ligand response properties of MphR, which is able to control gene expression in response to a molecular signal in cells. Furthermore, we studied molecular interactions between the TetR DNA-binding module and MphR ligand-binding module by using mutant analysis. Together, we demonstrated that TetR family regulators contain discrete and functional modules that can be used to build biological components with novel properties. This work highlights the utility of rational design as a means of creating modular parts for cell engineering and introduces new possibilities in rewiring cellular response pathways.
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Affiliation(s)
- Rey P Dimas
- Department of Biology, The University of Texas at Tyler, Tyler, TX 75799, USA
| | - Benjamin R Jordan
- Department of Biology, The University of Texas at Tyler, Tyler, TX 75799, USA.,Department of Pharmaceutical Sciences, Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, TX 75799, USA
| | - Xian-Li Jiang
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Catherine Martini
- Department of Biology, The University of Texas at Tyler, Tyler, TX 75799, USA
| | - Joseph S Glavy
- Department of Pharmaceutical Sciences, Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, TX 75799, USA
| | - Dustin P Patterson
- Department of Chemistry and Biochemistry, The University of Texas at Tyler, Tyler, TX 75799, USA
| | - Faruck Morcos
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Bioengineering, The University of Texas at Dallas, Richardson, TX 75080, USA.,Center for Systems Biology, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Clement T Y Chan
- Department of Biology, The University of Texas at Tyler, Tyler, TX 75799, USA.,Department of Chemistry and Biochemistry, The University of Texas at Tyler, Tyler, TX 75799, USA
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11
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van Veen HW, Singh H, Agboh K, Fagg LA, Guo D, Swain B, de Kruijf RF, Guffick C. Energy coupling in ABC exporters. Res Microbiol 2019; 170:392-398. [PMID: 31442612 DOI: 10.1016/j.resmic.2019.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/27/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022]
Abstract
Multidrug transporters are important and interesting molecular machines that extrude a wide variety of cytotoxic drugs from target cells. This review summarizes novel insights in the energetics and mechanisms of bacterial ATP-binding cassette multidrug transporters as well as recent advances connecting multidrug transport to ion and lipid translocation processes in other membrane proteins.
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Affiliation(s)
- Hendrik W van Veen
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.
| | - Himansha Singh
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Kelvin Agboh
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Lisa A Fagg
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Dawei Guo
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Brendan Swain
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Robbin F de Kruijf
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Charlotte Guffick
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
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12
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Duan Y, Liu T, Zhou Y, Dou T, Yang Q. Glycoside hydrolase family 18 and 20 enzymes are novel targets of the traditional medicine berberine. J Biol Chem 2018; 293:15429-15438. [PMID: 30135205 DOI: 10.1074/jbc.ra118.004351] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/03/2018] [Indexed: 02/01/2023] Open
Abstract
Berberine is a traditional medicine that has multiple medicinal and agricultural applications. However, little is known about whether berberine can be a bioactive molecule toward carbohydrate-active enzymes, which play numerous vital roles in the life process. In this study, berberine and its analogs were discovered to be competitive inhibitors of glycoside hydrolase family 20 β-N-acetyl-d-hexosaminidase (GH20 Hex) and GH18 chitinase from both humans and the insect pest Ostrinia furnacalis Berberine and its analog SYSU-1 inhibit insect GH20 Hex from O. furnacalis (OfHex1), with Ki values of 12 and 8.5 μm, respectively. Co-crystallization of berberine and its analog SYSU-1 in complex with OfHex1 revealed that the positively charged conjugate plane of berberine forms π-π stacking interactions with Trp490, which are vital to its inhibitory activity. Moreover, the 1,3-dioxole group of berberine binds an unexplored pocket formed by Trp322, Trp483, and Val484, which also contributes to its inhibitory activity. Berberine was also found to be an inhibitor of human GH20 Hex (HsHexB), human GH18 chitinase (HsCht and acidic mammalian chitinase), and insect GH18 chitinase (OfChtI). Besides GH18 and GH20 enzymes, berberine was shown to weakly inhibit human GH84 O-GlcNAcase (HsOGA) and Saccharomyces cerevisiae GH63 α-glucosidase I (ScGluI). By analyzing the published crystal structures, berberine was revealed to bind with its targets in an identical mechanism, namely via π-π stacking and electrostatic interactions with the aromatic and acidic residues in the binding pockets. This paper reports new molecular targets of berberine and may provide a berberine-based scaffold for developing multitarget drugs.
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Affiliation(s)
- Yanwei Duan
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024
| | - Tian Liu
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024,
| | - Yong Zhou
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024
| | - Tongyi Dou
- the School of Life Science and Medicine, Dalian University of Technology, Panjin 124221, and
| | - Qing Yang
- From the State Key Laboratory of Fine Chemical Engineering, School of Life Science and Biotechnology and School of Software, Dalian University of Technology, Dalian 116024, .,the Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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13
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Shrestha JP, Baker C, Kawasaki Y, Subedi YP, Vincent de Paul NN, Takemoto JY, Chang CWT. Synthesis and bioactivity investigation of quinone-based dimeric cationic triazolium amphiphiles selective against resistant fungal and bacterial pathogens. Eur J Med Chem 2016; 126:696-704. [PMID: 27951483 DOI: 10.1016/j.ejmech.2016.12.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/19/2016] [Accepted: 12/02/2016] [Indexed: 10/20/2022]
Abstract
A series of synthetic dimeric cationic anthraquinone analogs (CAAs) with potent antimicrobial activities against a broad range of fungi and bacteria were developed. These compounds were prepared in 2-3 steps with high overall yield and possess alkyl chain, azole, quinone, and quaternary ammonium complexes (QACs). In vitro biological evaluations reveal prominent inhibitory activities of lead compounds against several drug-susceptible and drug-resistant fungal and bacterial strains, including MRSA, VRE, Candida albicans and Aspergillus flavus. Mode of action investigation reveals that the synthesized dimeric CAA's can disrupt the membrane integrity of fungi. Computational studies reveal possible designs that can revive the activity of QACs against drug-resistant bacteria. Cytotoxicity assays in SKOV-3, a cancer cell line, show that the lead compounds are selectively toxic to fungi and bacteria over human cells.
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Affiliation(s)
- Jaya P Shrestha
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322-0300, USA
| | - Coleman Baker
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322-0300, USA
| | - Yukie Kawasaki
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA
| | - Yagya P Subedi
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322-0300, USA
| | | | - Jon Y Takemoto
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA
| | - Cheng-Wei Tom Chang
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322-0300, USA.
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14
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Relocation of active site carboxylates in major facilitator superfamily multidrug transporter LmrP reveals plasticity in proton interactions. Sci Rep 2016; 6:38052. [PMID: 27917857 PMCID: PMC5137110 DOI: 10.1038/srep38052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/03/2016] [Indexed: 12/30/2022] Open
Abstract
The expression of polyspecific membrane transporters is one important mechanism by which cells can obtain resistance to structurally different antibiotics and cytotoxic agents. These transporters reduce intracellular drug concentrations to subtoxic levels by mediating drug efflux across the cell envelope. The major facilitator superfamily multidrug transporter LmrP from Lactococcus lactis catalyses drug efflux in a membrane potential and chemical proton gradient-dependent fashion. To enable the interaction with protons and cationic substrates, LmrP contains catalytic carboxyl residues on the surface of a large interior chamber that is formed by transmembrane helices. These residues co-localise together with polar and aromatic residues, and are predicted to be present in two clusters. To investigate the functional role of the catalytic carboxylates, we generated mutant proteins catalysing membrane potential-independent dye efflux by removing one of the carboxyl residues in Cluster 1. We then relocated this carboxyl residue to six positions on the surface of the interior chamber, and tested for restoration of wildtype energetics. The reinsertion at positions towards Cluster 2 reinstated the membrane potential dependence of dye efflux. Our data uncover a remarkable plasticity in proton interactions in LmrP, which is a consequence of the flexibility in the location of key residues that are responsible for proton/multidrug antiport.
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15
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Insight into determinants of substrate binding and transport in a multidrug efflux protein. Sci Rep 2016; 6:22833. [PMID: 26961153 PMCID: PMC4785361 DOI: 10.1038/srep22833] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/24/2016] [Indexed: 11/09/2022] Open
Abstract
Multidrug resistance arising from the activity of integral membrane transporter proteins presents a global public health threat. In bacteria such as Escherichia coli, transporter proteins belonging to the major facilitator superfamily make a considerable contribution to multidrug resistance by catalysing efflux of myriad structurally and chemically different antimicrobial compounds. Despite their clinical relevance, questions pertaining to mechanistic details of how these promiscuous proteins function remain outstanding, and the role(s) played by individual amino acid residues in recognition, binding and subsequent transport of different antimicrobial substrates by multidrug efflux members of the major facilitator superfamily requires illumination. Using in silico homology modelling, molecular docking and mutagenesis studies in combination with substrate binding and transport assays, we identified several amino acid residues that play important roles in antimicrobial substrate recognition, binding and transport by Escherichia coli MdtM, a representative multidrug efflux protein of the major facilitator superfamily. Furthermore, our studies suggested that ‘aromatic clamps’ formed by tyrosine and phenylalanine residues located within the substrate binding pocket of MdtM may be important for antimicrobial substrate recognition and transport by the protein. Such ‘clamps’ may be a structurally and functionally important feature of all major facilitator multidrug efflux proteins.
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16
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Juárez JF, Liu H, Zamarro MT, McMahon S, Liu H, Naismith JH, Eberlein C, Boll M, Carmona M, Díaz E. Unraveling the specific regulation of the central pathway for anaerobic degradation of 3-methylbenzoate. J Biol Chem 2015; 290:12165-83. [PMID: 25795774 PMCID: PMC4424350 DOI: 10.1074/jbc.m115.637074] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Indexed: 01/06/2023] Open
Abstract
The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the β-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB1, and P3R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds.
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Affiliation(s)
- Javier F Juárez
- From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Huixiang Liu
- the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and
| | - María T Zamarro
- From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Stephen McMahon
- the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and
| | - Huanting Liu
- the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and
| | - James H Naismith
- the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and
| | - Christian Eberlein
- the Institute for Biology II, University of Freiburg, 79104 Freiburg, Germany
| | - Matthias Boll
- the Institute for Biology II, University of Freiburg, 79104 Freiburg, Germany
| | - Manuel Carmona
- From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Eduardo Díaz
- From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain,
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17
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Hayashi T, Tanaka Y, Sakai N, Okada U, Yao M, Watanabe N, Tamura T, Tanaka I. Structural and genomic DNA analysis of the putative TetR transcriptional repressor SCO7518 from Streptomyces coelicolor A3(2). FEBS Lett 2014; 588:4311-8. [PMID: 25305383 DOI: 10.1016/j.febslet.2014.09.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/18/2014] [Accepted: 09/24/2014] [Indexed: 10/24/2022]
Abstract
SCO7518 is a protein of unknown function from Streptomyces coelicolor A3(2) that has been classified into the TetR transcriptional regulator family. In this study, a crystal structure of SCO7518 was determined at 2.29Å resolution. The structure is a homodimer of protomers that comprise an N-terminal DNA-binding domain and a C-terminal dimerization and regulatory domain, and possess a putative ligand-binding cavity. Genomic systematic evolution of ligands by exponential enrichment and electrophoretic mobility shift assays revealed that SCO7518 specifically binds to an operator sequence located upstream of the sco7519 gene, which encodes a maltose O-acetyltransferase. These results suggest that SCO7518 is a transcriptional repressor of sco7519 expression.
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Affiliation(s)
- Takeshi Hayashi
- Department of Food and Fermentation Science, Faculty of Food and Nutrition, Beppu University, Beppu, Oita 874-8501, Japan; Food Science and Nutrition, Graduate School of Food Science and Nutrition, Beppu University, Beppu, Oita 874-8501, Japan
| | - Yoshikazu Tanaka
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Naoki Sakai
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Ui Okada
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Min Yao
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan; Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Nobuhisa Watanabe
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan; Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tomohiro Tamura
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan
| | - Isao Tanaka
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan; Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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18
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Fujihashi M, Nakatani T, Hirooka K, Matsuoka H, Fujita Y, Miki K. Structural characterization of a ligand-bound form of Bacillus subtilis FadR involved in the regulation of fatty acid degradation. Proteins 2014; 82:1301-10. [PMID: 24356978 DOI: 10.1002/prot.24496] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/28/2013] [Accepted: 12/09/2013] [Indexed: 11/05/2022]
Abstract
Bacillus subtilis FadR (FadR(Bs)), a member of the TetR family of bacterial transcriptional regulators, represses five fad operons including 15 genes, most of which are involved in β-oxidation of fatty acids. FadR(Bs) binds to the five FadR(Bs) boxes in the promoter regions and the binding is specifically inhibited by long-chain (C14-C20 ) acyl-CoAs, causing derepression of the fad operons. To elucidate the structural mechanism of this regulator, we have determined the crystal structures of FadR(Bs) proteins prepared with and without stearoyl(C18)-CoA. The crystal structure without adding any ligand molecules unexpectedly includes one small molecule, probably dodecyl(C12)-CoA derived from the Escherichia coli host, in its homodimeric structure. Also, we successfully obtained the structure of the ligand-bound form of the FadR(Bs) dimer by co-crystallization, in which two stearoyl-CoA molecules are accommodated, with the binding mode being essentially equivalent to that of dodecyl-CoA. Although the acyl-chain-binding cavity of FadR(Bs) is mainly hydrophobic, a hydrophilic patch encompasses the C1-C10 carbons of the acyl chain. This accounts for the previous report that the DNA binding of FadR(Bs) is specifically inhibited by the long-chain acyl-CoAs but not by the shorter ones. Structural comparison of the ligand-bound and unliganded subunits of FadR(Bs) revealed three regions around residues 21-31, 61-76, and 106-119 that were substantially changed in response to the ligand binding, and particularly with respect to the movements of Leu108 and Arg109. Site-directed mutagenesis of these residues revealed that Arg109, but not Leu108, is a key residue for maintenance of the DNA-binding affinity of FadR(Bs).
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Affiliation(s)
- Masahiro Fujihashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
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19
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Sawai H, Yamanaka M, Sugimoto H, Shiro Y, Aono S. Structural basis for the transcriptional regulation of heme homeostasis in Lactococcus lactis. J Biol Chem 2012; 287:30755-68. [PMID: 22798069 DOI: 10.1074/jbc.m112.370916] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although heme is a crucial element for many biological processes including respiration, heme homeostasis should be regulated strictly due to the cytotoxicity of free heme molecules. Numerous lactic acid bacteria, including Lactococcus lactis, acquire heme molecules exogenously to establish an aerobic respiratory chain. A heme efflux system plays an important role for heme homeostasis to avoid cytotoxicity of acquired free heme, but its regulatory mechanism is not clear. Here, we report that the transcriptional regulator heme-regulated transporter regulator (HrtR) senses and binds a heme molecule as its physiological effector to regulate the expression of the heme-efflux system responsible for heme homeostasis in L. lactis. To elucidate the molecular mechanisms of how HrtR senses a heme molecule and regulates gene expression for the heme efflux system, we determined the crystal structures of the apo-HrtR·DNA complex, apo-HrtR, and holo-HrtR at a resolution of 2.0, 3.1, and 1.9 Å, respectively. These structures revealed that HrtR is a member of the TetR family of transcriptional regulators. The residue pair Arg-46 and Tyr-50 plays a crucial role for specific DNA binding through hydrogen bonding and a CH-π interaction with the DNA bases. HrtR adopts a unique mechanism for its functional regulation upon heme sensing. Heme binding to HrtR causes a coil-to-helix transition of the α4 helix in the heme-sensing domain, which triggers a structural change of HrtR, causing it to dissociate from the target DNA for derepression of the genes encoding the heme efflux system. HrtR uses a unique heme-sensing motif with bis-His (His-72 and His-149) ligation to the heme, which is essential for the coil-to-helix transition of the α4 helix upon heme sensing.
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Affiliation(s)
- Hitomi Sawai
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
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20
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Schaedler TA, Tong Z, van Veen HW. The multidrug transporter LmrP protein mediates selective calcium efflux. J Biol Chem 2012; 287:27682-90. [PMID: 22730320 DOI: 10.1074/jbc.m112.372334] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
LmrP is a major facilitator superfamily multidrug transporter from Lactococcus lactis that mediates the efflux of cationic amphiphilic substrates from the cell in a proton-motive force-dependent fashion. Interestingly, motif searches and docking studies suggested the presence of a putative Ca(2+)-binding site close to the interface between the two halves of inward facing LmrP. Binding experiments with radioactive (45)Ca(2+) demonstrated the presence of a high affinity Ca(2+)-binding site in purified LmrP, with an apparent K(d) of 7.2 μm, which is selective for Ca(2+) and Ba(2+) but not for Mn(2+), Mg(2+), or Co(2+). Consistent with our structure model and analogous to crystal structures of EF hand Ca(2+)-binding proteins, two carboxylates (Asp-235 and Glu-327) were found to be critical for (45)Ca(2+) binding. Using (45)Ca(2+) and a fluorescent Ca(2+)-selective probe, calcium transport measurements in intact cells, inside-out membrane vesicles, and proteoliposomes containing functionally reconstituted purified protein provided strong evidence for active efflux of Ca(2+) by LmrP with an apparent K(t) of 8.6 μm via electrogenic exchange with three or more protons. These observations demonstrate for the first time that LmrP mediates selective calcium/proton antiport and raise interesting questions about the functional and physiological links between this reaction and that of multidrug transport.
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21
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Peters KM, Brooks BE, Schumacher MA, Skurray RA, Brennan RG, Brown MH. A single acidic residue can guide binding site selection but does not govern QacR cationic-drug affinity. PLoS One 2011; 6:e15974. [PMID: 21264225 PMCID: PMC3022030 DOI: 10.1371/journal.pone.0015974] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 12/07/2010] [Indexed: 11/19/2022] Open
Abstract
Structures of the multidrug-binding repressor protein QacR with monovalent and bivalent cationic drugs revealed that the carboxylate side-chains of E90 and E120 were proximal to the positively charged nitrogens of the ligands ethidium, malachite green and rhodamine 6G, and therefore may contribute to drug neutralization and binding affinity. Here, we report structural, biochemical and in vivo effects of substituting these glutamate residues. Unexpectedly, substitutions had little impact on ligand affinity or in vivo induction capabilities. Structures of QacR(E90Q) and QacR(E120Q) with ethidium or malachite green took similar global conformations that differed significantly from all previously described QacR-drug complexes but still prohibited binding to cognate DNA. Strikingly, the QacR(E90Q)-rhodamine 6G complex revealed two mutually exclusive rhodamine 6G binding sites. Despite multiple structural changes, all drug binding was essentially isoenergetic. Thus, these data strongly suggest that rather than contributing significantly to ligand binding affinity, the role of acidic residues lining the QacR multidrug-binding pocket is primarily to attract and guide cationic drugs to the "best available" positions within the pocket that elicit QacR induction.
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Affiliation(s)
- Kate M. Peters
- School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia,
| | - Benjamin E. Brooks
- Department of Biochemistry and Molecular Biology, MD Anderson Cancer Centre Houston, Texas, United States of America
| | - Maria A. Schumacher
- Department of Biochemistry and Molecular Biology, MD Anderson Cancer Centre Houston, Texas, United States of America
| | - Ronald A. Skurray
- School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia,
| | - Richard G. Brennan
- Department of Biochemistry and Molecular Biology, MD Anderson Cancer Centre Houston, Texas, United States of America
- * E-mail: (MHB); (RGB)
| | - Melissa H. Brown
- School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia,
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
- * E-mail: (MHB); (RGB)
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22
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Schaedler TA, van Veen HW. A flexible cation binding site in the multidrug major facilitator superfamily transporter LmrP is associated with variable proton coupling. FASEB J 2010; 24:3653-61. [PMID: 20472749 DOI: 10.1096/fj.10-156927] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The multidrug major facilitator superfamily transporter LmrP from Lactococcus lactis mediates protonmotive-force dependent efflux of amphiphilic ligands from the cell. We compared the role of membrane-embedded carboxylates in transport and binding of divalent cationic propidium and monovalent cationic ethidium. D235N, E327Q, and D142N replacements each resulted in loss of electrogenicity in the propidium efflux reaction, pointing to electrogenic 3H(+)/propidium(2+) antiport. During ethidium efflux, single D142N and D235N replacements resulted in apparent loss of electrogenicity, whereas the E327Q substitution did not affect the energetics, consistent with electrogenic 2H(+)/ethidium(+) antiport. Different roles of carboxylates were also observed in fluorescence anisotropy-based ligand-binding assays. Whereas D235 and E327 were both involved in propidium binding, the loss of one of these carboxylates could be compensated for by the other in ethidium binding. The D142N replacement did not affect the binding of either ligand. These data point to the presence of a dedicated proton binding site containing D142, and a flexible proton/ligand binding site containing D235 and E327, the contributions to proton and ligand binding of which depend on the chemical structure of the bound ligand. Our findings provide the first evidence that multidrug transport by secondary-active transporters can be associated with variable ion coupling.
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Affiliation(s)
- Theresia A Schaedler
- Department of Pharmacology, University of Cambridge, Tennis Court Rd., Cambridge CB2 1PD, UK
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23
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Wade H. MD recognition by MDR gene regulators. Curr Opin Struct Biol 2010; 20:489-96. [DOI: 10.1016/j.sbi.2010.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 06/02/2010] [Indexed: 11/28/2022]
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24
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Peters KM, Sharbeen G, Theis T, Skurray RA, Brown MH. Biochemical characterization of the multidrug regulator QacR distinguishes residues that are crucial to multidrug binding and induction of qacA transcription. Biochemistry 2009; 48:9794-800. [PMID: 19761200 DOI: 10.1021/bi901102h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Staphylococcus aureus transcription factor QacR regulates expression of the qacA multidrug efflux determinant. In response to binding cationic lipophilic compounds, including ethidium and rhodamine 6G, QacR dissociates from the qacA operator alleviating repression. Such ligand binding uniformly induces a coil-to-helix transition of residues Thr(89)-Tyr(93) revealing an asymmetric binding pocket in QacR containing two distinct subpockets. Here, the functional significance of hydrophobic, aromatic, and polar residues characteristic of the rhodamine 6G pocket and the proximal Tyr(92), proposed to facilitate the transcriptionally active conformation, was examined. Notably, the presence of Tyr(92) was not essential for QacR structural changes between DNA-bound and induced conformations. Furthermore, although mutation of the majority of residues contacting rhodamine 6G exerted moderate effects on QacR-rhodamine 6G binding, mutation of Leu(54) and Gln(96), and cumulative mutations involving these with Tyr(93) and Tyr(123), imparted a dramatic decrease in QacR-rhodamine 6G binding affinity. This equated with impaired dissociation of QacR from its operator DNA in the presence of this ligand in S. aureus, delineating the important role of these residues in the QacR-rhodamine 6G interaction. Additionally, despite maintaining a high affinity for ethidium, QacR mutants involving Leu(54), Tyr(93), Gln(96), and Tyr(123), which denote the interface between the rhodamine 6G and ethidium subpockets, were unable to be induced from operator DNA in the presence of ethidium in S. aureus. This highlights the significant contribution of these residues to QacR-mediated derepression of qacA transcription following ligand binding in the distal subpocket and may be important for the general mechanism irrespective of the ligand bound.
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Affiliation(s)
- Kate M Peters
- School of Biological Sciences, A12, University of Sydney, Sydney, NSW, Australia
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25
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Gutmann DAP, Ward A, Urbatsch IL, Chang G, van Veen HW. Understanding polyspecificity of multidrug ABC transporters: closing in on the gaps in ABCB1. Trends Biochem Sci 2009; 35:36-42. [PMID: 19819701 DOI: 10.1016/j.tibs.2009.07.009] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 07/27/2009] [Accepted: 07/31/2009] [Indexed: 11/26/2022]
Abstract
Multidrug ABC transporters can transport a wide range of drugs from the cell. Ongoing studies of the prototype mammalian multidrug resistance ATP-binding cassette transporter P-glycoprotein (ABCB1) have revealed many intriguing functional and biochemical features. However, a gap remains in our knowledge regarding the molecular basis of its broad specificity for structurally unrelated ligands. Recently, the first crystal structures of ligand-free and ligand-bound ABCB1 showed ligand binding in a cavity between its two membrane domains, and earlier observations on polyspecificity can now be interpreted in a structural context. Comparison of the new ABCB1 crystal structures with structures of bacterial homologs suggests a critical role for an axial rotation of transmembrane helices for high-affinity binding and low-affinity release of ligands during transmembrane transport.
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Structural plasticity and distinct drug-binding modes of LfrR, a mycobacterial efflux pump regulator. J Bacteriol 2009; 191:7531-7. [PMID: 19820093 DOI: 10.1128/jb.00631-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The TetR-like transcriptional repressor LfrR controls the expression of the gene encoding the Mycobacterium smegmatis efflux pump LfrA, which actively extrudes fluoroquinolones, cationic dyes, and anthracyclines from the cell and promotes intrinsic antibiotic resistance. The crystal structure of the apoprotein form of the repressor reveals a structurally asymmetric homodimer exhibiting local unfolding and a blocked drug-binding site, emphasizing the significant conformational plasticity of the protein necessary for DNA and multidrug recognition. Crystallographic and calorimetric studies of LfrR-drug complexes further confirm the intrinsic flexibility of the homodimer, which provides a dynamic mechanism to broaden multidrug binding specificity and may be a general property of transcriptional repressors regulating microbial efflux pump expression.
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Alternating access of the putative substrate-binding chamber in the ABC transporter MsbA. J Mol Biol 2009; 393:574-85. [PMID: 19715704 DOI: 10.1016/j.jmb.2009.08.051] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 08/16/2009] [Accepted: 08/20/2009] [Indexed: 11/23/2022]
Abstract
MsbA is an ATP-binding cassette transporter from Escherichia coli that is involved in trafficking lipid A across the inner membrane. ATP-binding cassette transporters harness the free energy of ATP binding and hydrolysis to drive the uphill translocation of substrates against their concentration gradients. A model of protein motion coupling energy input to work was inspired by crystallographic snapshots of MsbA. Central to this model is a switch in the accessibility of a transmembrane chamber, implicated in substrate binding, from an inward- to an outward-facing configuration. Here, we used spin labeling and electron paramagnetic resonance spectroscopy to systematically explore rearrangements in MsbA structure during the ATP hydrolysis cycle. Spin-label accessibility and local dynamics were determined in liposomes for the nucleotide-free intermediate and the transition state of ATP hydrolysis. The changes in the electron paramagnetic resonance parameters between these two intermediates fit a global pattern consistent with alternating access of the chamber. In the transition state of ATP hydrolysis, spin labels on the cytoplasmic side report increased dynamic restrictions and reduced water accessibility, while those on the extracellular side report increased water penetration. Furthermore, spin-label mobility and accessibility as well as their changes are consistent with those expected based on the crystal structures. The reversal in chamber hydration is likely to reduce the free energy of amphipathic substrate binding and promote translocation across the membrane.
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Gannon MK, Holt JJ, Bennett SM, Wetzel BR, Loo TW, Bartlett MC, Clarke DM, Sawada GA, Higgins JW, Tombline G, Raub TJ, Detty MR. Rhodamine inhibitors of P-glycoprotein: an amide/thioamide "switch" for ATPase activity. J Med Chem 2009; 52:3328-41. [PMID: 19402665 DOI: 10.1021/jm900253g] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have examined 46 tetramethylrosamine/rhodamine derivatives with structural diversity in the heteroatom of the xanthylium core, the amino substituents of the 3- and 6-positions, and the alkyl, aryl, or heteroaryl group at the 9-substituent. These compounds were examined for affinity and ATPase stimulation in isolated MDR3 CL P-gp and human P-gp-His(10), for their ability to promote uptake of calcein AM and vinblastine in multidrug-resistant MDCKII-MDR1 cells, and for transport in monolayers of MDCKII-MDR1 cells. Thioamide 31-S gave K(M) of 0.087 microM in human P-gp. Small changes in structure among this set of compounds affected affinity as well as transport rate (or flux) even though all derivatives examined were substrates for P-gp. With isolated protein, tertiary amide groups dictate high affinity and high stimulation while tertiary thioamide groups give high affinity and inhibition of ATPase activity. In MDCKII-MDR1 cells, the tertiary thioamide-containing derivatives promote uptake of calcein AM and have very slow passive, absorptive, and secretory rates of transport relative to transport rates for tertiary amide-containing derivatives. Thioamide 31-S promoted uptake of calcein AM and inhibited efflux of vinblastine with IC(50)'s of approximately 2 microM in MDCKII-MDR1 cells.
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Affiliation(s)
- Michael K Gannon
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
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Hernández A, Maté MJ, Sánchez-Díaz PC, Romero A, Rojo F, Martínez JL. Structural and functional analysis of SmeT, the repressor of the Stenotrophomonas maltophilia multidrug efflux pump SmeDEF. J Biol Chem 2009; 284:14428-38. [PMID: 19324881 DOI: 10.1074/jbc.m809221200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Stenotrophomonas maltophilia is an opportunistic pathogen characterized for its intrinsic low susceptibility to several antibiotics. Part of this low susceptibility relies on the expression of chromosomally encoded multidrug efflux pumps, with SmeDEF being the most relevant antibiotic resistance efflux pump so far studied in this bacterial species. Expression of smeDEF is down-regulated by the SmeT repressor, encoded upstream smeDEF, in its complementary DNA strand. In the present article we present the crystal structure of SmeT and analyze its interactions with its cognate operator. Like other members of the TetR family of transcriptional repressors, SmeT behaves as a dimer and presents some common structural features with other TetR proteins like TtgR, QacR, and TetR. Differing from other TetR proteins for which the structure is available, SmeT turned out to have two extensions at the N and C termini that might be relevant for its function. Besides, SmeT presents the smallest binding pocket so far described in the TetR family of transcriptional repressors, which may correlate with a specific type and range of effectors. In vitro studies revealed that SmeT binds to a 28-bp pseudopalindromic region, forming two complexes. This operator region was found to overlap the promoters of smeT and smeDEF. This finding is consistent with a role for SmeT simultaneously down-regulating smeT and smeDEF transcription, likely by steric hindrance on RNA polymerase binding to DNA.
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Affiliation(s)
- Alvaro Hernández
- Centro Nacional del Biotecnología, Cantoblanco, 28049 Madrid, Spain
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