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R R, Thakur P, Kumar N, Saini N, Banerjee S, Singh RP, Patel M, Kumaran S. Multi-oligomeric and catalytically compromised serine acetyltransferase and cysteine regulatory complex of Mycobacterium tuberculosis. Biochimie 2024; 221:110-124. [PMID: 38311199 DOI: 10.1016/j.biochi.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 02/10/2024]
Abstract
l-cysteine, a primary building block of mycothiol, plays an essential role in the defense mechanism of Mycobacterium tuberculosis (Mtb). However, it is unclear how Mtb regulates cysteine biosynthesis as no study has reported the cysteine regulatory complex (CRC) in Mtb. Serine acetyltransferase (SAT) and cysteine synthase (CS) interact to form CRC. Although MtCS has been characterized well, minimal information is available on MtSAT, which synthesizes, O-acetylserine (OAS), the precursor of cysteine. This study fills the gap and provides experimental evidence for the presence of MtCRC and a non-canonical multi-oligomeric MtSAT. We employed multiple analytical methods to characterize the oligomeric and kinetic properties of MtSAT and MtCRC. Results show that MtSAT, lacking >75 N-terminal amino acids exists in three different assembly states; trimer, hexamer, and dodecamer, compared to the single hexameric state of SAT of other bacteria. While hexamers display the highest catalytic turnover, the trimer is the least active. The predominance of trimers at low physiologically relevant concentrations suggests that MtSAT displays the lowest catalytic potential known. Further, the catalytic potential of MtSAT is also significantly reduced in CRC state, in contrast to enhanced activity of SAT in CRC of other organisms. Our study provides insights into multi-oligomeric MtSAT with reduced catalytic potential and demonstrates that both MtSAT and MtCS of Mycobacterium interact to form CRC, although with altered catalytic properties. We discuss our results in light of the altered biochemistry of the last step of canonical sulfate-dependent cysteine biosynthesis of Mycobacterium.
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Affiliation(s)
- Rahisuddin R
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - Payal Thakur
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - Narender Kumar
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - Neha Saini
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - Shrijta Banerjee
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - Ravi Pratap Singh
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - Madhuri Patel
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India
| | - S Kumaran
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh, 160036, India.
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Tao Y, Zheng D, Zou W, Guo T, Liao G, Zhou W. Targeting the cysteine biosynthesis pathway in microorganisms: Mechanism, structure, and drug discovery. Eur J Med Chem 2024; 271:116461. [PMID: 38691891 DOI: 10.1016/j.ejmech.2024.116461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/16/2024] [Accepted: 04/27/2024] [Indexed: 05/03/2024]
Abstract
Owing to the global health crisis of resistant pathogenic infections, researchers are emphasizing the importance of novel prevention and control strategies. Existing antimicrobial drugs predominantly target a few pathways, and their widespread use has pervasively increased drug resistance. Therefore, it is imperative to develop new antimicrobial drugs with novel targets and chemical structures. The de novo cysteine biosynthesis pathway, one of the microbial metabolic pathways, plays a crucial role in pathogenicity and drug resistance. This pathway notably differs from that in humans, thereby representing an unexplored target for developing antimicrobial drugs. Herein, we have presented an overview of cysteine biosynthesis pathways and their roles in the pathogenicity of various microorganisms. Additionally, we have investigated the structure and function of enzymes involved in these pathways as well as have discussed drug design strategies and structure-activity relationships of the enzyme inhibitors. This review provides valuable insights for developing novel antimicrobials and offers new avenues to combat drug resistance.
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Affiliation(s)
- Ying Tao
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Dandan Zheng
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Wei Zou
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Ting Guo
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Guojian Liao
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China.
| | - Wei Zhou
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China.
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3
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Yu M, Tang Y, Lu L, Kong W, Ye J. CysB Is a Key Regulator of the Antifungal Activity of Burkholderia pyrrocinia JK-SH007. Int J Mol Sci 2023; 24:ijms24098067. [PMID: 37175772 PMCID: PMC10179380 DOI: 10.3390/ijms24098067] [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: 03/23/2023] [Revised: 04/19/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Burkholderia pyrrocinia JK-SH007 can effectively control poplar canker caused by pathogenic fungi. Its antifungal mechanism remains to be explored. Here, we characterized the functional role of CysB in B. pyrrocinia JK-SH007. This protein was shown to be responsible for the synthesis of cysteine and the siderophore ornibactin, as well as the antifungal activity of B. pyrrocinia JK-SH007. We found that deletion of the cysB gene reduced the antifungal activity and production of the siderophore ornibactin in B. pyrrocinia JK-SH007. However, supplementation with cysteine largely restored these two abilities in the mutant. Further global transcriptome analysis demonstrated that the amino acid metabolic pathway was significantly affected and that some sRNAs were significantly upregulated and targeted the iron-sulfur metabolic pathway by TargetRNA2 prediction. Therefore, we suggest that, in B. pyrrocinia JK-SH007, CysB can regulate the expression of genes related to Fe-S clusters in the iron-sulfur metabolic pathway to affect the antifungal activity of B. pyrrocinia JK-SH007. These findings provide new insights into the various biological functions regulated by CysB in B. pyrrocinia JK-SH007 and the relationship between iron-sulfur metabolic pathways and fungal inhibitory substances. Additionally, they lay the foundation for further investigation of the main antagonistic substances of B. pyrrocinia JK-SH007.
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Affiliation(s)
- Meng Yu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Yuwei Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Lanxiang Lu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Weiliang Kong
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Jianren Ye
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
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The Nervous System Contributes to the Tumorigenesis and Progression of Human Digestive Tract Cancer. J Immunol Res 2022; 2022:9595704. [PMID: 35295188 PMCID: PMC8920690 DOI: 10.1155/2022/9595704] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/09/2022] [Accepted: 02/14/2022] [Indexed: 11/17/2022] Open
Abstract
Tumors of the gastrointestinal tract are one of the highest incidences of morbidity and mortality in humans. Recently, a growing number of researchers have indicated that nerve fibers and nerve signals participate in tumorigenesis. The current overarching view based on the responses to therapy revealed that tumors are partly promoted by the tumor microenvironment (TME), endogenous oncogenic factors, and complex systemic processes. Homeostasis of the neuroendocrine-immune axis (NEI axis) maintains a healthy in vivo environment in humans, and dysfunction of the axis contributes to various cancers, including the digestive tract. Interestingly, nerves might promote tumor development via multiple mechanisms, including perineural invasion (PNI), central level regulation, NEI axis effect, and neurotransmitter induction. This review focuses on the association between digestive tumors and nerve regulation, including PNI, the NEI axis, stress, and neurotransmitters, as well as on the potential clinical application of neurotherapy, aiming to provide a new perspective on the management of digestive cancers.
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Shan X, Fu J, Li X, Peng X, Chen L. Comparative proteomics and secretomics revealed virulence, and coresistance-related factors in non O1/O139 Vibrio cholerae recovered from 16 species of consumable aquatic animals. J Proteomics 2022; 251:104408. [PMID: 34737110 DOI: 10.1016/j.jprot.2021.104408] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/12/2021] [Accepted: 10/13/2021] [Indexed: 02/06/2023]
Abstract
Vibrio cholerae can cause pandemic cholera in humans. The bacterium resides in aquatic environments worldwide. Identification of risk factors of V. cholerae in aquatic products is imperative for assuming food safety. In this study, we determined virulence-associated genes, cross-resistance between antibiotics and heavy metals, and genome fingerprinting profiles of non O1/O139 V. cholerae isolates (n = 20) recovered from 16 species of consumable aquatic animals. Secretomes and proteomes of V. cholerae with distinct genotypes and phenotypes were obtained by using two-dimensional gel electrophoresis (2D-GE) and/or liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. Comparative secretomic analysis revealed 4 common and 45 differential extracellular proteins among 20 V. cholerae strains, including 13 virulence- and 8 resistance-associated proteins. A total of 21,972 intracellular proteins were identified, and comparative proteomic analysis revealed 215 common and 913 differential intracellular proteins, including 22 virulence- and 8 resistance-associated proteins. Additionally, different secretomes and proteomes were observed between V. cholerae isolates of fish and shellfish origins. A number of novel proteins with unknown function and strain-specific proteins were also discovered in the V. cholerae isolates. SIGNIFICANCE: V. cholerae can cause pandemic cholera in humans. The bacterium is distributed in aquatic environments worldwide. Identification of risk factors of V. cholerae in aquatic products is imperative for assuming food safety. Non-O1/O139 V. cholerae has been reported to cause sporadic cholera-like diarrhea and bacteremia diseases, which indicates virulence factors rather than the major cholera toxin (CT) exist. This study for the first time investigated proteomes and secretomes of non-O1/O139 V. cholerae originating from aquatic animals. This resulted in the identification of a number of virulence and coresistance-related factors, as well as novel proteins and strain-specific proteins in V. cholerae isolates recovered from 16 species of consumable aquatic animals. These results fill gaps for better understanding of pathogenesis and resistance of V. cholerae, and also support the increasing need for novel diagnosis and vaccine targets against the leading waterborne pathogen worldwide.
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Affiliation(s)
- Xinying Shan
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Junfeng Fu
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Xiaohui Li
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Xu Peng
- Archaea Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lanming Chen
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), China Ministry of Agriculture, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
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6
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Pavone M, Raboni S, Marchetti M, Annunziato G, Bettati S, Papotti B, Marchi C, Carosati E, Pieroni M, Campanini B, Costantino G. Exploring the chemical space around N-(5-nitrothiazol-2-yl)-1,2,3-thiadiazole-4-carboxamide, a hit compound with serine acetyltransferase (SAT) inhibitory properties. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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7
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Serine acetyltransferase from Neisseria gonorrhoeae; structural and biochemical basis of inhibition. Biochem J 2021; 479:57-74. [PMID: 34890451 PMCID: PMC8786284 DOI: 10.1042/bcj20210564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/18/2021] [Accepted: 12/10/2021] [Indexed: 11/17/2022]
Abstract
Serine acetyltransferase (SAT) catalyzes the first step in the two-step pathway to synthesize L-cysteine in bacteria and plants. SAT synthesizes O-acetylserine from substrates L‑serine and acetyl coenzyme A and is a key enzyme for regulating cellular cysteine levels by feedback inhibition of L-cysteine, and its involvement in the cysteine synthase complex. We have performed extensive structural and kinetic characterization of the SAT enzyme from the antibiotic-resistant pathogen Neisseria gonorrhoeae. Using X-ray crystallography, we have solved the structures of NgSAT with the non-natural ligand, L-malate (present in the crystallization screen) to 2.01 Å and with the natural substrate L-serine (2.80 Å) bound. Both structures are hexamers, with each monomer displaying the characteristic left-handed parallel β-helix domain of the acyltransferase superfamily of enzymes. Each structure displays both extended and closed conformations of the C-terminal tail.  L‑malate bound in the active site results in an interesting mix of open and closed active site conformations, exhibiting a structural change mimicking the conformation of cysteine (inhibitor) bound structures from other organisms. Kinetic characterization shows competitive inhibition of L-cysteine with substrates L-serine and acetyl coenzyme A. The SAT reaction represents a key point for the regulation of cysteine biosynthesis and controlling cellular sulfur due to feedback inhibition by L-cysteine and formation of the cysteine synthase complex. Data presented here provide the structural and mechanistic basis for inhibitor design and given this enzyme is not present in humans could be explored to combat the rise of extensively antimicrobial-resistant N. gonorrhoeae.
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8
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Phung C, Wilson TB, Quinteros JA, Scott PC, Moore RJ, Van TTH. Enhancement of Campylobacter hepaticus culturing to facilitate downstream applications. Sci Rep 2021; 11:20802. [PMID: 34675257 PMCID: PMC8531295 DOI: 10.1038/s41598-021-00277-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/30/2021] [Indexed: 11/13/2022] Open
Abstract
Campylobacter hepaticus causes Spotty Liver Disease (SLD) in chickens. C. hepaticus is fastidious and slow-growing, presenting difficulties when growing this bacterium for the preparation of bacterin vaccines and experimental disease challenge trials. This study applied genomic analysis and in vitro experiments to develop an enhanced C. hepaticus liquid culture method. In silico analysis of the anabolic pathways encoded by C. hepaticus revealed that the bacterium is unable to biosynthesise L-cysteine, L-lysine and L-arginine. It was found that L-cysteine added to Brucella broth, significantly enhanced the growth of C. hepaticus, but L-lysine or L-arginine addition did not enhance growth. Brucella broth supplemented with L-cysteine (0.4 mM), L-glutamine (4 mM), and sodium pyruvate (10 mM) gave high-density growth of C. hepaticus and resulted in an almost tenfold increase in culture density compared to the growth in Brucella broth alone (log10 = 9.3 vs 8.4 CFU/mL). The type of culture flask used also significantly affected C. hepaticus culture density. An SLD challenge trial demonstrated that C. hepaticus grown in the enhanced culture conditions retained full virulence. The enhanced liquid culture method developed in this study enables the efficient production of bacterial biomass and therefore facilitates further studies of SLD biology and vaccine development.
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Affiliation(s)
- Canh Phung
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia
| | | | | | | | - Robert J Moore
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia.
| | - Thi Thu Hao Van
- School of Science, RMIT University, Bundoora West Campus, Bundoora, VIC, Australia
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9
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A Competitive O-Acetylserine Sulfhydrylase Inhibitor Modulates the Formation of Cysteine Synthase Complex. Catalysts 2021. [DOI: 10.3390/catal11060700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cysteine is the main precursor of sulfur-containing biological molecules in bacteria and contributes to the control of the cell redox state. Hence, this amino acid plays an essential role in microbial survival and pathogenicity and the reductive sulfate assimilation pathway is considered a promising target for the development of new antibacterials. Serine acetyltransferase (SAT) and O-acetylserine sulfhydrylase (OASS-A), the enzymes catalyzing the last two steps of cysteine biosynthesis, engage in the formation of the cysteine synthase (CS) complex. The interaction between SAT and OASS-A finely tunes cysteine homeostasis, and the development of inhibitors targeting either protein–protein interaction or the single enzymes represents an attractive strategy to undermine bacterial viability. Given the peculiar mode of interaction between SAT and OASS-A, which exploits the insertion of SAT C-terminal sequence into OASS-A active site, we tested whether a recently developed competitive inhibitor of OASS-A exhibited any effect on the CS stability. Through surface plasmon resonance spectroscopy, we (i) determined the equilibrium constant for the Salmonella Typhimurium CS complex formation and (ii) demonstrated that the inhibitor targeting OASS-A active site affects CS complex formation. For comparison, the Escherichia coli CS complex was also investigated, with the aim of testing the potential broad-spectrum activity of the candidate antimicrobial compound.
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Rosa B, Dickinson ER, Marchetti M, Campanini B, Pioselli B, Bettati S, Rand KD. Revealing the Dynamic Allosteric Changes Required for Formation of the Cysteine Synthase Complex by Hydrogen-Deuterium Exchange MS. Mol Cell Proteomics 2021; 20:100098. [PMID: 34022432 PMCID: PMC8253905 DOI: 10.1016/j.mcpro.2021.100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 05/14/2021] [Indexed: 11/30/2022] Open
Abstract
CysE and CysK, the last two enzymes of the cysteine biosynthetic pathway, engage in a bienzyme complex, cysteine synthase, with yet incompletely characterized three-dimensional structure and regulatory function. Being absent in mammals, the two enzymes and their complex are attractive targets for antibacterial drugs. We have used hydrogen/deuterium exchange MS to unveil how complex formation affects the conformational dynamics of CysK and CysE. Our results support a model where CysE is present in solution as a dimer of trimers, and each trimer can bind one CysK homodimer. When CysK binds to one CysE monomer, intratrimer allosteric communication ensures conformational and dynamic symmetry within the trimer. Furthermore, a long-range allosteric signal propagates through CysE to induce stabilization of the interface between the two CysE trimers, preparing the second trimer for binding the second CysK with a nonrandom orientation. These results provide new molecular insights into the allosteric formation of the cysteine synthase complex and could help guide antibacterial drug design. HDX-MS reveals complex formation impact on conformational dynamics of CysK and CysE. CysK binding ensures conformational symmetry within the CysE trimer. Long-range allostery propagates through CysE stabilizing the inter-trimer interface. Insights into the allostery of CS complex could help guide antibacterial drug design.
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Affiliation(s)
- Brenda Rosa
- Biopharmanet-TEC Interdepartmental Center, University di Parma, Parma, Italy
| | - Eleanor R Dickinson
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Copenhagen O, Denmark
| | | | | | | | - Stefano Bettati
- Biopharmanet-TEC Interdepartmental Center, University di Parma, Parma, Italy; Department of Medicine and Surgery, University of Parma, Parma, Italy; Institute of Biophysics, CNR, Pisa, Italy.
| | - Kasper Dyrberg Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Copenhagen O, Denmark.
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Annunziato G, Spadini C, Franko N, Storici P, Demitri N, Pieroni M, Flisi S, Rosati L, Iannarelli M, Marchetti M, Magalhaes J, Bettati S, Mozzarelli A, Cabassi CS, Campanini B, Costantino G. Investigational Studies on a Hit Compound Cyclopropane-Carboxylic Acid Derivative Targeting O-Acetylserine Sulfhydrylase as a Colistin Adjuvant. ACS Infect Dis 2021; 7:281-292. [PMID: 33513010 DOI: 10.1021/acsinfecdis.0c00378] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Antibacterial adjuvants are of great significance, since they allow the therapeutic dose of conventional antibiotics to be lowered and reduce the insurgence of antibiotic resistance. Herein, we report that an O-acetylserine sulfhydrylase (OASS) inhibitor can be used as a colistin adjuvant to treat infections caused by Gram-positive and Gram-negative pathogens. A compound that binds OASS with a nM dissociation constant was tested as an adjuvant of colistin against six critical pathogens responsible for infections spreading worldwide, Escherichia coli, Salmonella enterica serovar Typhimurium, Klebisiella pneumoniae, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Staphylococcus pseudintermedius. The compound showed promising synergistic or additive activities against all of them. Knockout experiments confirmed the intracellular target engagement supporting the proposed mechanism of action. Moreover, compound toxicity was evaluated by means of its hemolytic activity against sheep defibrinated blood cells, showing a good safety profile. The 3D structure of the compound in complex with OASS was determined at 1.2 Å resolution by macromolecular crystallography, providing for the first time structural insights about the nature of the interaction between the enzyme and this class of competitive inhibitors. Our results provide a robust proof of principle supporting OASS as a potential nonessential antibacterial target to develop a new class of adjuvants and the structural basis for further structure-activity relationship studies.
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Affiliation(s)
- Giannamaria Annunziato
- P4T Group, Department of Food and Drugs, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Costanza Spadini
- Operative Unit of Animals Infectious Diseases, Department of Veterinary Science, University of Parma, via del Taglio, 8, 43126 Parma, Italy
| | - Nina Franko
- Laboratory of Biochemistry and Molecular Biology, Department of Food and Drugs, University of Parma, via Parco Area delle Scienze 23/A, 43124 Parma, Italy
| | - Paola Storici
- Elettra - Sincrotrone Trieste S.C.p.A., SS 14
- km 163,5 in AREA Science Park, 34149 Trieste, Italy
| | - Nicola Demitri
- Elettra - Sincrotrone Trieste S.C.p.A., SS 14
- km 163,5 in AREA Science Park, 34149 Trieste, Italy
| | - Marco Pieroni
- P4T Group, Department of Food and Drugs, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Sara Flisi
- Operative Unit of Animals Infectious Diseases, Department of Veterinary Science, University of Parma, via del Taglio, 8, 43126 Parma, Italy
| | - Lucrezia Rosati
- Operative Unit of Animals Infectious Diseases, Department of Veterinary Science, University of Parma, via del Taglio, 8, 43126 Parma, Italy
| | - Mattia Iannarelli
- Operative Unit of Animals Infectious Diseases, Department of Veterinary Science, University of Parma, via del Taglio, 8, 43126 Parma, Italy
| | - Marialaura Marchetti
- Biopharmanet-TEC Interdepartmental Center, University of Parma, 43124 Parma, Italy
| | - Joana Magalhaes
- P4T Group, Department of Food and Drugs, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Stefano Bettati
- Department of Medicine and Surgery, University of Parma, via Volturno, 39, 43125 Parma, Italy
- Biopharmanet-TEC Interdepartmental Center, University of Parma, 43124 Parma, Italy
- Institute of Biophysics, CNR, 56124 Pisa, Italy
| | - Andrea Mozzarelli
- Laboratory of Biochemistry and Molecular Biology, Department of Food and Drugs, University of Parma, via Parco Area delle Scienze 23/A, 43124 Parma, Italy
- Biopharmanet-TEC Interdepartmental Center, University of Parma, 43124 Parma, Italy
- Institute of Biophysics, CNR, 56124 Pisa, Italy
| | - Clotilde Silvia Cabassi
- Operative Unit of Animals Infectious Diseases, Department of Veterinary Science, University of Parma, via del Taglio, 8, 43126 Parma, Italy
| | - Barbara Campanini
- Laboratory of Biochemistry and Molecular Biology, Department of Food and Drugs, University of Parma, via Parco Area delle Scienze 23/A, 43124 Parma, Italy
- Biopharmanet-TEC Interdepartmental Center, University of Parma, 43124 Parma, Italy
| | - Gabriele Costantino
- P4T Group, Department of Food and Drugs, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
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12
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Combination of SAXS and Protein Painting Discloses the Three-Dimensional Organization of the Bacterial Cysteine Synthase Complex, a Potential Target for Enhancers of Antibiotic Action. Int J Mol Sci 2019; 20:ijms20205219. [PMID: 31640223 PMCID: PMC6829319 DOI: 10.3390/ijms20205219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/10/2019] [Accepted: 09/17/2019] [Indexed: 01/03/2023] Open
Abstract
The formation of multienzymatic complexes allows for the fine tuning of many aspects of enzymatic functions, such as efficiency, localization, stability, and moonlighting. Here, we investigated, in solution, the structure of bacterial cysteine synthase (CS) complex. CS is formed by serine acetyltransferase (CysE) and O-acetylserine sulfhydrylase isozyme A (CysK), the enzymes that catalyze the last two steps of cysteine biosynthesis in bacteria. CysK and CysE have been proposed as potential targets for antibiotics, since cysteine and related metabolites are intimately linked to protection of bacterial cells against redox damage and to antibiotic resistance. We applied a combined approach of small-angle X-ray scattering (SAXS) spectroscopy and protein painting to obtain a model for the solution structure of CS. Protein painting allowed the identification of protein–protein interaction hotspots that were then used as constrains to model the CS quaternary assembly inside the SAXS envelope. We demonstrate that the active site entrance of CysK is involved in complex formation, as suggested by site-directed mutagenesis and functional studies. Furthermore, complex formation involves a conformational change in one CysK subunit that is likely transmitted through the dimer interface to the other subunit, with a regulatory effect. Finally, SAXS data indicate that only one active site of CysK is involved in direct interaction with CysE and unambiguously unveil the quaternary arrangement of CS.
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13
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Magalhães J, Franko N, Annunziato G, Pieroni M, Benoni R, Nikitjuka A, Mozzarelli A, Bettati S, Karawajczyk A, Jirgensons A, Campanini B, Costantino G. Refining the structure-activity relationships of 2-phenylcyclopropane carboxylic acids as inhibitors of O-acetylserine sulfhydrylase isoforms. J Enzyme Inhib Med Chem 2018; 34:31-43. [PMID: 30362368 PMCID: PMC6217552 DOI: 10.1080/14756366.2018.1518959] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The lack of efficacy of current antibacterials to treat multidrug resistant bacteria poses a life-threatening alarm. In order to develop enhancers of the antibacterial activity, we carried out a medicinal chemistry campaign aiming to develop inhibitors of enzymes that synthesise cysteine and belong to the reductive sulphur assimilation pathway, absent in mammals. Previous studies have provided a novel series of inhibitors for O-acetylsulfhydrylase – a key enzyme involved in cysteine biosynthesis. Despite displaying nanomolar affinity, the most active representative of the series was not able to interfere with bacterial growth, likely due to poor permeability. Therefore, we rationally modified the structure of the hit compound with the aim of promoting their passage through the outer cell membrane porins. The new series was evaluated on the recombinant enzyme from Salmonella enterica serovar Typhimurium, with several compounds able to keep nanomolar binding affinity despite the extent of chemical manipulation.
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Affiliation(s)
- Joana Magalhães
- a P4T group, Department of Food and Drug, University of Parma, Parma, Italy
| | - Nina Franko
- b Laboratory of Biochemistry and Molecular Biology, Department of Food and Drug , University of Parma , Parma , Italy
| | | | - Marco Pieroni
- a P4T group, Department of Food and Drug, University of Parma, Parma, Italy
| | - Roberto Benoni
- b Laboratory of Biochemistry and Molecular Biology, Department of Food and Drug , University of Parma , Parma , Italy
| | - Anna Nikitjuka
- c Latvian Institute of Organic Synthesis , Riga , Latvia
| | - Andrea Mozzarelli
- b Laboratory of Biochemistry and Molecular Biology, Department of Food and Drug , University of Parma , Parma , Italy.,d National Institute of Biostructures and Biosystems , Rome , Italy.,e Institute of Biophysics , Pisa , Italy
| | - Stefano Bettati
- b Laboratory of Biochemistry and Molecular Biology, Department of Food and Drug , University of Parma , Parma , Italy.,f Department of Neurosciences , University of Parma , Parma , Italy
| | | | | | - Barbara Campanini
- b Laboratory of Biochemistry and Molecular Biology, Department of Food and Drug , University of Parma , Parma , Italy
| | - Gabriele Costantino
- a P4T group, Department of Food and Drug, University of Parma, Parma, Italy.,h Centro Interdipartimentale Misure (CIM)'G. Casnati', University of Parma , Parma , Italy
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14
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Benoni R, Beck CM, Garza-Sánchez F, Bettati S, Mozzarelli A, Hayes CS, Campanini B. Activation of an anti-bacterial toxin by the biosynthetic enzyme CysK: mechanism of binding, interaction specificity and competition with cysteine synthase. Sci Rep 2017; 7:8817. [PMID: 28821763 PMCID: PMC5562914 DOI: 10.1038/s41598-017-09022-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/20/2017] [Indexed: 12/20/2022] Open
Abstract
Contact-dependent growth inhibition (CDI) is a wide-spread mechanism of inter-bacterial competition. CDI+ bacteria deliver CdiA-CT toxins into neighboring bacteria and produce specific immunity proteins that protect against self-intoxication. The CdiA-CT toxin from uropathogenic Escherichia coli 536 is a latent tRNase that is only active when bound to the cysteine biosynthetic enzyme CysK. Remarkably, the CysK:CdiA-CT binding interaction mimics the ‘cysteine synthase’ complex of CysK:CysE. The C-terminal tails of CysE and CdiA-CT each insert into the CysK active-site cleft to anchor the respective complexes. The dissociation constant for CysK:CdiA-CT (Kd ~ 11 nM) is comparable to that of the E. coli cysteine synthase complex (Kd ~ 6 nM), and both complexes bind through a two-step mechanism with a slow isomerization phase after the initial encounter. However, the second-order rate constant for CysK:CdiA-CT binding is two orders of magnitude slower than that of the cysteine synthase complex, suggesting that CysE should outcompete the toxin for CysK occupancy. However, we find that CdiA-CT can effectively displace CysE from pre-formed cysteine synthase complexes, enabling toxin activation even in the presence of excess competing CysE. This adventitious binding, coupled with the very slow rate of CysK:CdiA-CT dissociation, ensures robust nuclease activity in target bacteria.
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Affiliation(s)
- Roberto Benoni
- Dipartimento di Medicina e Chirurgia, Università di Parma, Parma, Italy.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha, Czech Republic
| | - Christina M Beck
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, USA.,Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fernando Garza-Sánchez
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Stefano Bettati
- Dipartimento di Medicina e Chirurgia, Università di Parma, Parma, Italy.,Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
| | - Andrea Mozzarelli
- Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy.,Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Christopher S Hayes
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, USA. .,Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Barbara Campanini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy.
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