1
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Singh M, Dhanwal A, Verma A, Augustin L, Kumari N, Chakraborti S, Agarwal N, Sriram D, Dey RJ. Discovery of potent antimycobacterial agents targeting lumazine synthase (RibH) of Mycobacterium tuberculosis. Sci Rep 2024; 14:12170. [PMID: 38806590 PMCID: PMC11133327 DOI: 10.1038/s41598-024-63051-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 05/24/2024] [Indexed: 05/30/2024] Open
Abstract
Tuberculosis (TB) continues to be a global health crisis, necessitating urgent interventions to address drug resistance and improve treatment efficacy. In this study, we validate lumazine synthase (RibH), a vital enzyme in the riboflavin biosynthetic pathway, as a potential drug target against Mycobacterium tuberculosis (M. tb) using a CRISPRi-based conditional gene knockdown strategy. We employ a high-throughput molecular docking approach to screen ~ 600,000 compounds targeting RibH. Through in vitro screening of 55 shortlisted compounds, we discover 3 compounds that exhibit potent antimycobacterial activity. These compounds also reduce intracellular burden of M. tb during macrophage infection and prevent the resuscitation of the nutrient-starved persister bacteria. Moreover, these three compounds enhance the bactericidal effect of first-line anti-TB drugs, isoniazid and rifampicin. Corroborating with the in silico predicted high docking scores along with favourable ADME and toxicity profiles, all three compounds demonstrate binding affinity towards purified lumazine synthase enzyme in vitro, in addition these compounds exhibit riboflavin displacement in an in vitro assay with purified lumazine synthase indicative of specificity of these compounds to the active site. Further, treatment of M. tb with these compounds indicate reduced production of flavin adenine dinucleotide (FAD), the ultimate end product of the riboflavin biosynthetic pathway suggesting the action of these drugs on riboflavin biosynthesis. These compounds also show acceptable safety profile in mammalian cells, with a high selective index. Hence, our study validates RibH as an important drug target against M. tb and identifies potent antimycobacterial agents.
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Affiliation(s)
- Monica Singh
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Anannya Dhanwal
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Arpita Verma
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Linus Augustin
- Translational Health Science and Technology Institute, Faridabad, Haryana, 121001, India
| | - Niti Kumari
- National Institute of Animal Biotechnology (NIAB), Hyderabad, Telangana, 500032, India
| | - Soumyananda Chakraborti
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
- National Institute of Malaria Research, Indian Council of Medical Research (ICMR), New Delhi, 110077, India
| | - Nisheeth Agarwal
- Translational Health Science and Technology Institute, Faridabad, Haryana, 121001, India
| | - Dharmarajan Sriram
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India
| | - Ruchi Jain Dey
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India.
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2
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Schwarz MGA, Correa PR, Almeida PSL, Mendonça-Lima L. Mycobacterium bovis BCG dodecin gene codes a functional protein despite of a start codon mutation. Tuberculosis (Edinb) 2023; 143:102400. [PMID: 37672955 DOI: 10.1016/j.tube.2023.102400] [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: 03/20/2023] [Revised: 08/14/2023] [Accepted: 08/30/2023] [Indexed: 09/08/2023]
Abstract
Dodecin is a dodecamer involved in flavin homeostasis, with interesting temperature and osmolarity endurance features in Mycobacterium tuberculosis. A single nucleotide polymorphism in the gene's start codon in BCG, converting ATG to ACG, is predicted to generate a N-terminal shorter isoform, lacking the first 7 amino acids. We previously reported that the shortened recombinant protein has reduced extremophilic features. Here we investigate if within the mycobacterial context dodecin can be produced from both alleles, carrying ATG and ACG start codons. Reporter gene assays using mcherry cloned downstream and in phase to both M.tb and BCG "upstream" regions confirms production of functional proteins. Complementation with both dod alleles similarly enhances M. smegmatis growth after entry into logarithmic phase and exposure to hydrogen peroxide, possibly implicating this protein in oxidative stress response mechanisms. Altogether these data indicate that BCG dodecin is indeed produced, notwithstanding in lower levels compared to M.tb, conferring similar phenotypes, even with the SNP altering the M.tb ATG start codon to the BCG ACG. This protein might be an interesting drug target for the development of new therapeutics against tuberculosis.
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Affiliation(s)
| | - Paloma Rezende Correa
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil.
| | - Paula Silva Lacerda Almeida
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil.
| | - Leila Mendonça-Lima
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil.
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3
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Jaroensuk J, Chuaboon L, Kesornpun C, Chaiyen P. Enzymes in riboflavin biosynthesis: Potential antibiotic drug targets. Arch Biochem Biophys 2023; 748:109762. [PMID: 37739114 DOI: 10.1016/j.abb.2023.109762] [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: 07/16/2023] [Revised: 09/13/2023] [Accepted: 09/19/2023] [Indexed: 09/24/2023]
Abstract
The rapid resistance of pathogens to antibiotics has emerged as a major threat to global health. Identification of new antibiotic targets is thus needed for developing alternative drugs. Genes encoding enzymes involved in the biosynthesis of riboflavin and flavin cofactors (FMN/FAD) are attractive targets because these enzymatic reactions are necessary for most bacteria to synthesize flavin cofactors for use in their central metabolic reactions. Moreover, humans lack most of these enzymes because we uptake riboflavin from our diet. This review discusses the current knowledge of enzymes involved in bacterial biosynthesis of riboflavin and other flavin cofactors, as well as the functions of the FMN riboswitch. Here, we highlight recent progress in the structural and mechanistic characterization, and inhibition of GTP cyclohydrolase II (GCH II), lumazine synthase (LS), riboflavin synthase (RFS), FAD synthetase (FADS), and FMN riboswitch, which have been identified as plausible antibiotic targets. As the structures and functions of these enzymes and regulatory systems are not completely understood, they are attractive as subjects for future in-depth biochemical and biophysical analysis.
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Affiliation(s)
- Juthamas Jaroensuk
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Wangchan, Rayong, 21210, Thailand
| | - Litavadee Chuaboon
- School of Pharmacy and Biomass and Oil Palm Center of Excellence, Walailak University, Nakhon Si Thammarat, 80160, Thailand
| | - Chatchai Kesornpun
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Wangchan, Rayong, 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Wangchan, Rayong, 21210, Thailand.
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4
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Islam Z, Kumar P. Inhibitors of riboflavin biosynthetic pathway enzymes as potential antibacterial drugs. Front Mol Biosci 2023; 10:1228763. [PMID: 37496776 PMCID: PMC10366380 DOI: 10.3389/fmolb.2023.1228763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/03/2023] [Indexed: 07/28/2023] Open
Abstract
Multiple drug resistance is the main obstacle in the treatment of bacterial diseases. Resistance against antibiotics demands the exploration of new antimicrobial drug targets. A variety of in silico and genetic approaches show that the enzymes of the riboflavin biosynthetic pathway are crucial for the survival of bacteria. This pathway is absent in humans thus enzymes of the riboflavin biosynthetic pathway are emerging drug targets for resistant pathogenic bacterial strains. Exploring the structural details, their mechanism of action, intermediate elucidation, and interaction analysis would help in designing suitable inhibitors of these enzymes. The riboflavin biosynthetic pathway consists of seven distinct enzymes, namely, 3,4-dihydroxy-2-butanone 4-phosphate synthase, GTP cyclohydrolase II, pyrimidine deaminase/reductase, phosphatase, lumazine synthase, and riboflavin synthase. The present review summarizes the research work that has been carried out on these enzymes in terms of their structures, active site architectures, and molecular mechanism of catalysis. This review also walks through small molecule inhibitors that have been developed against several of these enzymes.
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Affiliation(s)
- Zeyaul Islam
- Qatar Biomedical Research Institute (QBRI), Qatar Foundation, Hamad Bin Khalifa University, Doha, Qatar
| | - Pankaj Kumar
- Department of Biochemistry, Jamia Hamdard, New Delhi, India
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5
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Witt KD. Role of MHC class I pathways in Mycobacterium tuberculosis antigen presentation. Front Cell Infect Microbiol 2023; 13:1107884. [PMID: 37009503 PMCID: PMC10050577 DOI: 10.3389/fcimb.2023.1107884] [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: 11/25/2022] [Accepted: 02/23/2023] [Indexed: 03/17/2023] Open
Abstract
MHC class I antigen processing is an underappreciated area of nonviral host–pathogen interactions, bridging both immunology and cell biology, where the pathogen’s natural life cycle involves little presence in the cytoplasm. The effective response to MHC-I foreign antigen presentation is not only cell death but also phenotypic changes in other cells and stimulation of the memory cells ready for the next antigen reoccurrence. This review looks at the MHC-I antigen processing pathway and potential alternative sources of the antigens, focusing on Mycobacterium tuberculosis (Mtb) as an intracellular pathogen that co-evolved with humans and developed an array of decoy strategies to survive in a hostile environment by manipulating host immunity to its own advantage. As that happens via the selective antigen presentation process, reinforcement of the effective antigen recognition on MHC-I molecules may stimulate subsets of effector cells that act earlier and more locally. Vaccines against tuberculosis (TB) could potentially eliminate this disease, yet their development has been slow, and success is limited in the context of this global disease’s spread. This review’s conclusions set out potential directions for MHC-I-focused approaches for the next generation of vaccines.
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Affiliation(s)
- Karolina D. Witt
- Pandemic Sciences Institute, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- *Correspondence: Karolina D. Witt,
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6
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Fu B, Ying J, Chen Q, Zhang Q, Lu J, Zhu Z, Yu P. Enhancing the biosynthesis of riboflavin in the recombinant Escherichia coli BL21 strain by metabolic engineering. Front Microbiol 2023; 13:1111790. [PMID: 36726568 PMCID: PMC9885008 DOI: 10.3389/fmicb.2022.1111790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/29/2022] [Indexed: 01/18/2023] Open
Abstract
In this study, to construct the riboflavin-producing strain R1, five key genes, ribA, ribB, ribC, ribD, and ribE, were cloned and ligated to generate the plasmid pET-AE, which was overexpressed in Escherichia coli BL21. The R1 strain accumulated 182.65 ± 9.04 mg/l riboflavin. Subsequently, the R2 strain was constructed by the overexpression of zwf harboring the constructed plasmid pAC-Z in the R1 strain. Thus, the level of riboflavin in the R2 strain increased to 319.01 ± 20.65 mg/l (74.66% increase). To further enhance ribB transcript levels and riboflavin production, the FMN riboswitch was deleted from E. coli BL21 with CRISPR/Cas9 to generate the R3 strain. The R4 strain was constructed by cotransforming pET-AE and pAC-Z into the R3 strain. Compared to those of E. coli BL21, the ribB transcript levels of R2 and R4 improved 2.78 and 3.05-fold, respectively. The R4 strain accumulated 437.58 ± 14.36 mg/l riboflavin, increasing by 37.17% compared to the R2 strain. These results suggest that the deletion of the FMN riboswitch can improve the transcript level of ribB and facilitate riboflavin production. A riboflavin titer of 611.22 ± 11.25 mg/l was achieved under the optimal fermentation conditions. Ultimately, 1574.60 ± 109.32 mg/l riboflavin was produced through fed-batch fermentation with 40 g/l glucose. This study contributes to the industrial production of riboflavin by the recombinant E. coli BL21.
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Affiliation(s)
- Bing Fu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang, China,College of Forestry Science and Technology, Lishui Vocational and Technical College, Lishui, Zhejiang, China
| | - Junhui Ying
- College of Forestry Science and Technology, Lishui Vocational and Technical College, Lishui, Zhejiang, China
| | - Qingwei Chen
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang, China
| | - Qili Zhang
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang, China
| | - Jiajie Lu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang, China
| | - Zhiwen Zhu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang, China
| | - Ping Yu
- College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang, China,*Correspondence: Ping Yu,
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7
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Lu G, Ou K, Zhang Y, Zhang H, Feng S, Yang Z, Sun G, Liu J, Wei S, Pan S, Chen Z. Structural Analysis, Multi-Conformation Virtual Screening and Molecular Simulation to Identify Potential Inhibitors Targeting pS273R Proteases of African Swine Fever Virus. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020570. [PMID: 36677630 PMCID: PMC9866604 DOI: 10.3390/molecules28020570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/26/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023]
Abstract
The African Swine Fever virus (ASFV) causes an infectious viral disease in pigs of all ages. The development of antiviral drugs primarily aimed at inhibition of proteases required for the proteolysis of viral polyproteins. In this study, the conformation of the pS273R protease in physiological states were investigated, virtually screened the multi-protein conformation of pS273R target proteins, combined various molecular docking scoring functions, and identified five potential drugs from the Food and Drug Administration drug library that may inhibit pS273R. Subsequent validation of the dynamic interactions of pS273R with the five putative inhibitors was achieved using molecular dynamics simulations and binding free energy calculations using the molecular mechanics/Poison-Boltzmann (Generalized Born) (MM/PB(GB)SA) surface area. These findings demonstrate that the arm domain and Thr159-Lys167 loop region of pS273R are significantly more flexible compared to the core structural domain, and the Thr159-Lys167 loop region can serve as a "gatekeeper" in the substrate channel. Leucovorin, Carboprost, Protirelin, Flavin Mononucleotide, and Lovastatin Acid all have Gibbs binding free energies with pS273R that were less than -20 Kcal/mol according to the MM/PBSA analyses. In contrast to pS273R in the free energy landscape, the inhibitor and drug complexes of pS273R showed distinct structural group distributions. These five drugs may be used as potential inhibitors of pS273R and may serve as future drug candidates for treating ASFV.
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Affiliation(s)
- Gen Lu
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
| | - Kang Ou
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
| | - Yihan Zhang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
| | - Huan Zhang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
| | - Shouhua Feng
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
| | - Zuofeng Yang
- The Preventive and Control Center of Animal Disease of Liaoning Province, Liaoning Agricultural Development Service Center, No. 95, Renhe Road, Shenbei District, Shenyang 110164, China
| | - Guo Sun
- Qianyuanhao Biological Co., Ltd., Building 20, District 11, No. 188 South Fourth Ring West Road, Fengtai District, Beijing 100070, China
| | - Jinling Liu
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
- Correspondence: (J.L.); (S.W.); (S.P.); (Z.C.); Tel.: +86-13022453165 (J.L.); Fax: +86-24-88487156 (J.L.)
| | - Shu Wei
- The Preventive and Control Center of Animal Disease of Liaoning Province, Liaoning Agricultural Development Service Center, No. 95, Renhe Road, Shenbei District, Shenyang 110164, China
- Correspondence: (J.L.); (S.W.); (S.P.); (Z.C.); Tel.: +86-13022453165 (J.L.); Fax: +86-24-88487156 (J.L.)
| | - Shude Pan
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
- Correspondence: (J.L.); (S.W.); (S.P.); (Z.C.); Tel.: +86-13022453165 (J.L.); Fax: +86-24-88487156 (J.L.)
| | - Zeliang Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, No. 120, Dongling Road, Shenhe District, Shenyang 110866, China
- Correspondence: (J.L.); (S.W.); (S.P.); (Z.C.); Tel.: +86-13022453165 (J.L.); Fax: +86-24-88487156 (J.L.)
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8
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Therapeutic Target Identification and Inhibitor Screening against Riboflavin Synthase of Colorectal Cancer Associated Fusobacterium nucleatum. Cancers (Basel) 2022; 14:cancers14246260. [PMID: 36551744 PMCID: PMC9777469 DOI: 10.3390/cancers14246260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/11/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Colorectal cancer (CRC) ranks third among all cancers in terms of prevalence. There is growing evidence that gut microbiota has a role in the development of colorectal cancer. Fusobacterium nucleatum is overrepresented in the gastrointestinal tract and tumor microenvironment of patients with CRC. This suggests the role of F. nucleatum as a potential risk factor in the development of CRC. Hence, we aimed to explore whole genomes of F. nucleatum strains related to CRC to predict potential therapeutic markers through a pan-genome integrated subtractive genomics approach. In the current study, we identified 538 proteins as essential for F. nucleatum survival, 209 non-homologous to a human host, and 12 as drug targets. Eventually, riboflavin synthase (RiS) was selected as a therapeutic target for further processing. Three different inhibitor libraries of lead-like natural products, i.e., cyanobactins (n = 237), streptomycins (n = 607), and marine bacterial secondary metabolites (n = 1226) were screened against it. After the structure-based study, three compounds, i.e., CMNPD3609 (−7.63) > Malyngamide V (−7.03) > ZINC06804365 (−7.01) were prioritized as potential inhibitors of F. nucleatum. Additionally, the stability and flexibility of these compounds bound to RiS were determined via a molecular dynamics simulation of 50 ns. Results revealed the stability of these compounds within the binding pocket, after 5 ns. ADMET profiling showed compounds as drug-like, non-permeable to the blood brain barrier, non-toxic, and HIA permeable. Pan-genomics mediated drug target identification and the virtual screening of inhibitors is the preliminary step towards inhibition of this pathogenic oncobacterium and we suggest mouse model experiments to validate our findings.
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Giarimoglou N, Kouvela A, Maniatis A, Papakyriakou A, Zhang J, Stamatopoulou V, Stathopoulos C. A Riboswitch-Driven Era of New Antibacterials. Antibiotics (Basel) 2022; 11:antibiotics11091243. [PMID: 36140022 PMCID: PMC9495366 DOI: 10.3390/antibiotics11091243] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/01/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022] Open
Abstract
Riboswitches are structured non-coding RNAs found in the 5′ UTR of important genes for bacterial metabolism, virulence and survival. Upon the binding of specific ligands that can vary from simple ions to complex molecules such as nucleotides and tRNAs, riboswitches change their local and global mRNA conformations to affect downstream transcription or translation. Due to their dynamic nature and central regulatory role in bacterial metabolism, riboswitches have been exploited as novel RNA-based targets for the development of new generation antibacterials that can overcome drug-resistance problems. During recent years, several important riboswitch structures from many bacterial representatives, including several prominent human pathogens, have shown that riboswitches are ideal RNA targets for new compounds that can interfere with their structure and function, exhibiting much reduced resistance over time. Most interestingly, mainstream antibiotics that target the ribosome have been shown to effectively modulate the regulatory behavior and capacity of several riboswitches, both in vivo and in vitro, emphasizing the need for more in-depth studies and biological evaluation of new antibiotics. Herein, we summarize the currently known compounds that target several main riboswitches and discuss the role of mainstream antibiotics as modulators of T-box riboswitches, in the dawn of an era of novel inhibitors that target important bacterial regulatory RNAs.
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Affiliation(s)
- Nikoleta Giarimoglou
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Adamantia Kouvela
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Alexandros Maniatis
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Athanasios Papakyriakou
- Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Ag. Paraskevi, 15341 Athens, Greece
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | | | - Constantinos Stathopoulos
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
- Correspondence: ; Tel.: +30-2610-997932
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Kenjić N, Meneely KM, Wherritt DJ, Denler MC, Jackson TA, Moran GR, Lamb AL. Evidence for the Chemical Mechanism of RibB (3,4-Dihydroxy-2-butanone 4-phosphate Synthase) of Riboflavin Biosynthesis. J Am Chem Soc 2022; 144:12769-12780. [PMID: 35802469 PMCID: PMC9305975 DOI: 10.1021/jacs.2c03376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
RibB (3,4-dihydroxy-2-butanone 4-phosphate synthase)
is a magnesium-dependent
enzyme that excises the C4 of d-ribulose-5-phosphate (d-Ru5P) as formate. RibB generates the four-carbon substrate
for lumazine synthase that is incorporated into the xylene moiety
of lumazine and ultimately the riboflavin isoalloxazine. The reaction
was first identified by Bacher and co-workers in the 1990s, and their
chemical mechanism hypothesis became canonical despite minimal direct
evidence. X-ray crystal structures of RibB typically show two metal
ions when solved in the presence of non-native metals and/or liganding
non-substrate analogues, and the consensus hypothetical mechanism
has incorporated this cofactor set. We have used a variety of biochemical
approaches to further characterize the chemistry catalyzed by RibB
from Vibrio cholera (VcRibB). We show
that full activity is achieved at metal ion concentrations equal to
the enzyme concentration. This was confirmed by electron paramagnetic
resonance of the enzyme reconstituted with manganese and crystal structures
liganded with Mn2+ and a variety of sugar phosphates. Two
transient species prior to the formation of products were identified
using acid quench of single turnover reactions in combination with
NMR for singly and fully 13C-labeled d-Ru5P. These
data indicate that dehydration of C1 forms the first transient species,
which undergoes rearrangement by a 1,2 migration, fusing C5 to C3
and generating a hydrated C4 that is poised for elimination as formate.
Structures determined from time-dependent Mn2+ soaks of
VcRibB-d-Ru5P crystals show accumulation in crystallo of
the same intermediates. Collectively, these data reveal for the first
time crucial transient chemical states in the mechanism of RibB.
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Affiliation(s)
- Nikola Kenjić
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, United States
| | - Kathleen M Meneely
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, United States.,Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Daniel J Wherritt
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Melissa C Denler
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Timothy A Jackson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Graham R Moran
- Department of Chemistry and Biochemistry, University of Loyola, Chicago, Illinois 60660, United States
| | - Audrey L Lamb
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, United States.,Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
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11
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Bangalore PK, Pedapati RK, Pranathi AN, Batchu UR, Misra S, Estharala M, Sriram D, Kantevari S. Aryl-n-hexanamide linked enaminones of usnic acid as promising antimicrobial agents. Mol Divers 2022; 27:811-836. [PMID: 35608808 DOI: 10.1007/s11030-022-10456-y] [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: 03/05/2022] [Accepted: 04/28/2022] [Indexed: 11/30/2022]
Abstract
Lichen secondary metabolites are well explored medicinal agents with diverse pharmacological properties. One of the important antibiotic lichen secondary metabolites is usnic acid. Its diverse medicinal profiles prompted us to explore it as a potential antitubercular molecule. Towards this direction, continuing our efforts on the discovery and development of new analogs with potent antitubercular properties we designed, synthesized, and evaluated a set of 37 usnic acid enaminone-coupled aryl-n-hexanamides (3-39). The study yielded a 3,4-dimethoxyphenyl compound (13, 5.3 µM) as the most active anti-TB molecule. The docking studies were performed on 7 different enzymes to better understand the binding modes, where it was observed that compound 13 bound strongly with glucose dehydrogenase (Gscore: - 9.03). Further antibacterial investigations revealed compound 2 with potent inhibition on Salmonella typhi and Bacillus subtilis (MIC 3 µM) and MIC values of 7 and 14 µM on Streptococcus mutans and Escherichia coli respectively. Compound 19 (3-F-5-CF3-phenyl) displayed encouraging antibacterial profiles against E. coli, S. typhi and S. mutans with MIC values of 10 µM respectively. Interestingly, compound 20 (2,6-difluorophenyl) also displayed good antibacterial activity against E. coli with an MIC value of 6 µM. These encouraging pharmacological results will help for better designing and developing usnic acid-based semi-synthetic derivatives as potential antimicrobial agents. A set of 37 new usnic acid enaminone-coupled aryl-n-hexanamides were synthesized and evaluated as potential antimicrobial agents. Compound 13 was identified as the most active antitubercular molecule. 13 was further docked against 7 different enzymes of tuberculosis. The molecule displayed maximum binding energy with the enzyme Glucose dehydrogenase (Gscore: - 9.03), indicating that these hexanamides possibly act by inhibiting the glucose metabolic pathway of the bacterium. Surprisingly, the intermediate hexanoic acid 2 was identified as potent antibacterial agent, acting on both gram-positive and gram-negative bacterial strains (3-14 μM). The active compounds may be subjected to structural iterations to develop further leads.
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Affiliation(s)
- Pavan Kumar Bangalore
- Fluoro and Agrochemicals Division, CSIR- Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India. .,Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14850, USA.
| | - Ravi Kumar Pedapati
- Fluoro and Agrochemicals Division, CSIR- Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Abburi Naga Pranathi
- Fluoro and Agrochemicals Division, CSIR- Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Uma Rajeswari Batchu
- Applied Biology Division, CSIR- Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India
| | - Sunil Misra
- Applied Biology Division, CSIR- Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India
| | - Madhurekha Estharala
- Medicinal Chemistry and Antimycobacterial Research Laboratory, Pharmacy Group, Birla Institute of Technology and Science-Pilani, Hyderabad Campus, Jawahar Nagar, Hyderabad, Telangana, 500078, India
| | - Dharmarajan Sriram
- Medicinal Chemistry and Antimycobacterial Research Laboratory, Pharmacy Group, Birla Institute of Technology and Science-Pilani, Hyderabad Campus, Jawahar Nagar, Hyderabad, Telangana, 500078, India
| | - Srinivas Kantevari
- Fluoro and Agrochemicals Division, CSIR- Indian Institute of Chemical Technology, Hyderabad, Telangana, 500007, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India.
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12
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Shingare RD, MacMillan JB, Reddy DS. Antibiotic natural product hunanamycin A: Lead identification towards anti-Salmonella agents. Eur J Med Chem 2022; 236:114245. [DOI: 10.1016/j.ejmech.2022.114245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/10/2022] [Accepted: 02/26/2022] [Indexed: 11/30/2022]
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13
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Serral F, Pardo AM, Sosa E, Palomino MM, Nicolás MF, Turjanski AG, Ramos PIP, Fernández Do Porto D. Pathway Driven Target Selection in Klebsiella pneumoniae: Insights Into Carbapenem Exposure. Front Cell Infect Microbiol 2022; 12:773405. [PMID: 35174104 PMCID: PMC8841789 DOI: 10.3389/fcimb.2022.773405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/07/2022] [Indexed: 12/13/2022] Open
Abstract
Carbapenem-resistant Klebsiella pneumoniae (CR-KP) represents an emerging threat to public health. CR-KP infections result in elevated morbidity and mortality. This fact, coupled with their global dissemination and increasingly limited number of therapeutic options, highlights the urgency of novel antimicrobials. Innovative strategies linking genome-wide interrogation with multi-layered metabolic data integration can accelerate the early steps of drug development, particularly target selection. Using the BioCyc ontology, we generated and manually refined a metabolic network for a CR-KP, K. pneumoniae Kp13. Converted into a reaction graph, we conducted topological-based analyses in this network to prioritize pathways exhibiting druggable features and fragile metabolic points likely exploitable to develop novel antimicrobials. Our results point to the aptness of previously recognized pathways, such as lipopolysaccharide and peptidoglycan synthesis, and casts light on the possibility of targeting less explored cellular functions. These functions include the production of lipoate, trehalose, glycine betaine, and flavin, as well as the salvaging of methionine. Energy metabolism pathways emerged as attractive targets in the context of carbapenem exposure, targeted either alone or in conjunction with current therapeutic options. These results prompt further experimental investigation aimed at controlling this highly relevant pathogen.
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Affiliation(s)
- Federico Serral
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Agustin M. Pardo
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Ezequiel Sosa
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Mercedes Palomino
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Cdad. Universitaria, Buenos Aires, Argentina
| | - Marisa F. Nicolás
- Laboratório de Bioinformática (LABINFO), Laboratório Nacional de Computação Científica (LNCC), Petrópolis, Brazil
| | - Adrian G. Turjanski
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Cdad. Universitaria, Buenos Aires, Argentina
| | - Pablo Ivan P. Ramos
- Centro de Integração de Dados e Conhecimentos para a Saúde (CIDACS), Instituto Gonçalo Moniz, Fundação Oswaldo Cruz (Fiocruz - Bahia), Salvador, Brazil
- *Correspondence: Darío Fernández Do Porto, ; Pablo Ivan P. Ramos,
| | - Darío Fernández Do Porto
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Cdad. Universitaria, Buenos Aires, Argentina
- *Correspondence: Darío Fernández Do Porto, ; Pablo Ivan P. Ramos,
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14
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Farah N, Chin VK, Chong PP, Lim WF, Lim CW, Basir R, Chang SK, Lee TY. Riboflavin as a promising antimicrobial agent? A multi-perspective review. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100111. [PMID: 35199072 PMCID: PMC8848291 DOI: 10.1016/j.crmicr.2022.100111] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 12/29/2022] Open
Abstract
Riboflavin demonstrates antioxidant and photosensitizing properties. Riboflavin is able to induce ROS and modulate immune response. Riboflavin possesses potent antimicrobial activity when used alone or combined with other anti-infectives. The riboflavin biosynthesis pathway serves as an ideal drug target against microbes. UVA combination with riboflavin exhibits remarkable antimicrobial effects.
Riboflavin, or more commonly known as vitamin B2, forms part of the component of vitamin B complex. Riboflavin consisting of two important cofactors, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are involved in multiple oxidative-reduction processes and energy metabolism. Besides maintaining human health, different sources reported that riboflavin can inhibit or inactivate the growth of different pathogens including bacteria, viruses, fungi and parasites, highlighting the possible role of riboflavin as an antimicrobial agent. Moreover, riboflavin and flavins could produce reactive oxygen species (ROS) when exposed to light, inducing oxidative damage in cells and tissues, and thus are excellent natural photosensitizers. Several studies have illustrated the therapeutic efficacy of photoactivated riboflavin against nosocomial infections and multidrug resistant bacterial infections as well as microbial associated biofilm infections, revealing the potential role of riboflavin as a promising antimicrobial candidate, which could serve as one of the alternatives in fighting the global crisis of the emergence of antimicrobial resistance seen in different pathogenic microbes. Riboflavin could also be involved in modulating host immune responses, which might increase the pathogen clearance from host cells and increase host defense against microbial infections. Thus, the dual effects of riboflavin on both pathogens and host immunity, reflected by its potent bactericidal effect and alleviation of inflammation in host cells further imply that riboflavin could be a potential candidate for therapeutic intervention in resolving microbial infections. Hence, this review aimed to provide some insights on the promising role of riboflavin as an antimicrobial candidate and also a host immune-modulator from a multi-perspective view as well as to discuss the application and challenges on using riboflavin in photodynamic therapy against various pathogens and microbial biofilm-associated infections.
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Affiliation(s)
- Nuratiqah Farah
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, UPM, 43400, Serdang, Selangor, Malaysia
| | - Voon Kin Chin
- Department of Medical Microbiology, Faculty of Medicine and Health Sciences, UPM, 43400, Serdang, Selangor, Malaysia
| | - Pei Pei Chong
- School of Biosciences, Taylor's University, No 1, Jalan Taylor's, 47500 Subang Jaya, Selangor, Malaysia
| | - Wai Feng Lim
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA, Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor, Malaysia
| | - Chee Woei Lim
- Department of Medicine, Faculty of Medicine and Health Sciences, UPM, 43400, Serdang, Selangor, Malaysia
| | - Rusliza Basir
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, UPM, 43400, Serdang, Selangor, Malaysia
| | - Sui Kiat Chang
- Department of Horticulture, Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Key Laboratory of Post-Harvest Handling of Fruits, Ministry of Agriculture. South China Botanical Garden, Chinese Academy of Sciences. Guangzhou, 510650 China
| | - Tze Yan Lee
- Perdana University School of Liberal Arts, Science and Technology (PUScLST), Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Damansara Heights, 50490 Kuala Lumpur, Malaysia
- Corresponding author.
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15
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Abstract
To resolve the growing problem of drug resistance in the treatment of bacterial and fungal pathogens, specific cellular targets and pathways can be used as targets for new antimicrobial agents. Endogenous riboflavin biosynthesis is a conserved pathway that exists in most bacteria and fungi. In this review, the roles of endogenous and exogenous riboflavin in infectious disease as well as several antibacterial agents, which act as analogues of the riboflavin biosynthesis pathway, are summarized. In addition, the effects of exogenous riboflavin on immune cells, cytokines, and heat shock proteins are described. Moreover, the immune response of endogenous riboflavin metabolites in infectious diseases, recognized by MHC-related protein-1, and then presented to mucosal associated invariant T cells, is highlighted. This information will provide a strategy to identify novel drug targets as well as highlight the possible clinical use of riboflavin.
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Affiliation(s)
- Junwen Lei
- Molecular Biotechnology Platform, Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou People's Republic of China
| | - Caiyan Xin
- Molecular Biotechnology Platform, Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou People's Republic of China
| | - Wei Xiao
- Molecular Biotechnology Platform, Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou People's Republic of China
| | - Wenbi Chen
- Molecular Biotechnology Platform, Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou People's Republic of China
| | - Zhangyong Song
- Molecular Biotechnology Platform, Public Center of Experimental Technology, School of Basic Medical Sciences, Southwest Medical University, Luzhou People's Republic of China
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16
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Sieniawska E, Sawicki R, Marchev AS, Truszkiewicz W, Georgiev MI. Tanshinones from Salvia miltiorrhiza inhibit Mycobacterium tuberculosis via disruption of the cell envelope surface and oxidative stress. Food Chem Toxicol 2021; 156:112405. [PMID: 34273428 DOI: 10.1016/j.fct.2021.112405] [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: 05/27/2021] [Revised: 07/04/2021] [Accepted: 07/09/2021] [Indexed: 11/24/2022]
Abstract
The unique structure of Mycobacterium tuberculosis cell envelope provides impermeable barrier against environmental stimuli. In the situation that this barrier is disturbed Mycobacteria react at the transcriptional and translational level to redirect metabolic processes and to maintain integrity of the cell. In this work we aimed to explore the early metabolic response of M. tuberculosis to tanshinones, which are active antimycobacterial compounds of Salvia miltiorrhiza Bunge root. The investigation of the expression of sigma factors revealed the significant shifts in the general bacterial regulatory network, whereas LC-MS metabolomics evidenced the changes in the composition of bacterial cell envelope and indicated altered metabolic pathways. Tanshinones acted via the disruption of the cell envelope surface and generation of reactive oxygen species. Bacteria responded with overproduction of inner region of outer membrane, fluctuations in the production of glycerophosphoinositolglycans, as well as changes in the levels of mycobactins, accompanied by enrichment of metabolic pathways related to redox balance and repair of damages caused by tanshinones.
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Affiliation(s)
- Elwira Sieniawska
- Medical University of Lublin, Chair and Department of Pharmacognosy, Lublin, Poland.
| | - Rafal Sawicki
- Medical University of Lublin, Chair and Department of Biochemistry and Biotechnology, Lublin, Poland.
| | - Andrey S Marchev
- Bulgarian Academy of Sciences, The Stephan Angeloff Institute of Microbiology, Laboratory of Metabolomics, Plovdiv, Bulgaria; Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria.
| | - Wieslaw Truszkiewicz
- Medical University of Lublin, Chair and Department of Biochemistry and Biotechnology, Lublin, Poland.
| | - Milen I Georgiev
- Bulgarian Academy of Sciences, The Stephan Angeloff Institute of Microbiology, Laboratory of Metabolomics, Plovdiv, Bulgaria; Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria.
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17
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Harale B, Kidwai S, Ojha D, Singh M, Chouhan DK, Singh R, Khedkar V, Rode AB. Synthesis and evaluation of antimycobacterial activity of riboflavin derivatives. Bioorg Med Chem Lett 2021; 48:128236. [PMID: 34242760 DOI: 10.1016/j.bmcl.2021.128236] [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: 03/31/2021] [Revised: 06/21/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
The riboflavin biosynthetic pathway is a promising target for the development of novel antimycobacterial drugs given the lack of riboflavin transporter in M. tuberculosis. Herein, a series of riboflavin derivatives was designed, synthesized and screened for their antimycobacterial and antibacterial activity. The compounds 1a, 1b, 2a, 3a and 5a displayed noticeable antitubercular activity against M. tuberculosis with minimum inhibitory concentration (MIC99) in the range of 6.25 to 25 μM. The lead compound 5a had a selectivity index of 10.7 in the present study. The compounds 2a, 2b, 2c, 4c and 4d showed relatively low to moderate antibacterial activity (MIC = 100-200 μM) against gram-positive strains. Notably, the compounds do not show any inhibition against gram-negative strains even at 200 μM concentration. Further, molecular docking and binding experiments with representative flavin mononucleotide (FMN) riboswitch suggested that the riboflavin analogs exhibited antimycobacterial activity plausibly through FMN riboswitch-mediated repression of riboflavin biosynthesis. In addition to FMN riboswitch, flavoproteins involved in the flavin biosynthesis could also be target of riboflavin derivatives. In conclusion, the potency and low toxicity of riboflavin analogs particularly 5a (MIC99 = 6.25) make it a lead compound for the synthesis of new analogs for antimycobacterial therapy.
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Affiliation(s)
- Bhaiyyasaheb Harale
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad - Gurugram Expressway, Faridabad, Haryana 121001, India
| | - Saqib Kidwai
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad, Gurugram Expressway, Faridabad, Haryana 121001, India
| | - Divya Ojha
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad - Gurugram Expressway, Faridabad, Haryana 121001, India
| | - Manisha Singh
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad, Gurugram Expressway, Faridabad, Haryana 121001, India
| | - Dwarika Kumar Chouhan
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad - Gurugram Expressway, Faridabad, Haryana 121001, India
| | - Ramandeep Singh
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad, Gurugram Expressway, Faridabad, Haryana 121001, India
| | - Vijay Khedkar
- School of Pharmacy, Vishwakarma University, Pune 411048, Maharashtra, India
| | - Ambadas B Rode
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad - Gurugram Expressway, Faridabad, Haryana 121001, India.
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18
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Chen SC, Ye LC, Yen TM, Zhu RX, Li CY, Chang SC, Liaw SH, Hsu CH. Crystal structures of Aspergillus oryzae Rib2 deaminase: the functional mechanism involved in riboflavin biosynthesis. IUCRJ 2021; 8:549-558. [PMID: 34258004 PMCID: PMC8256712 DOI: 10.1107/s205225252100275x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/15/2021] [Indexed: 06/13/2023]
Abstract
Riboflavin serves as the direct precursor of the FAD/FMN coenzymes and is biosynthesized in most prokaryotes, fungi and plants. Fungal Rib2 possesses a deaminase domain for deamination of pyrimidine in the third step of riboflavin biosynthesis. Here, four high-resolution crystal structures of a Rib2 deaminase from Aspergillus oryzae (AoRib2) are reported which display three distinct occluded, open and complex forms that are involved in substrate binding and catalysis. In addition to the deaminase domain, AoRib2 contains a unique C-terminal segment which is rich in charged residues. Deletion of this unique segment has no effect on either enzyme activity or protein stability. Nevertheless, the C-terminal αF helix preceding the segment plays a role in maintaining protein stability and activity. Unexpectedly, AoRib2 is the first mononucleotide deaminase found to exist as a monomer, perhaps due to the assistance of its unique longer loops (Lβ1-β2, LαB-β3 and LαC-β4). These results form the basis for a molecular understanding of riboflavin biosynthesis in fungi and might assist in the development of antibiotics.
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Affiliation(s)
- Sheng-Chia Chen
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Li-Ci Ye
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
| | - Te-Ming Yen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 11217, Taiwan
| | - Ruei-Xin Zhu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
| | - Cheng-Yu Li
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - San-Chi Chang
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shwu-Huey Liaw
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan
- Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Chun-Hua Hsu
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
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19
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Yadav S, Shinde RN, Singh S, Karthikeyan S, Singh B. Structurally disordered C-terminal residues of GTP cyclohydrolase II are essential for its enzymatic activity. J Biomol Struct Dyn 2021; 40:9318-9331. [PMID: 34032179 DOI: 10.1080/07391102.2021.1926326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
GTP cyclohydrolase II (GCHII) is one of the rate limiting enzymes in riboflavin biosynthesis pathway and is shown to be a potential drug target for most of the pathogens. Previous biochemical and structural studies have identified the active site residues and elucidated the steps involved in the catalytic mechanism of GCHII. However, the last ∼20-25 C-terminal residues of GCHII remains unstructured in all the crystal structures determined to date and their role in the catalytic activity, if any, remains elusive. Therefore, to understand the role of these unstructured C-terminal residues, a series of C-terminal deletion mutants of GCHII from Helicobacter pylori (hGCHII) were generated and their catalytic activity was compared with its wild-type. Surprisingly, none of the C-terminal deletion mutants shows any enzymatic activity indicating that these are essential for GCHII function. To get additional insights for such loss of activity, homology models of full-length and deletion mutants of hGCHII in complex with GTP, Mg2+, and Zn2+ were generated and subjected to molecular dynamics simulation studies. The simulation studies show that a conserved histidine at 190th position from the unstructured C-terminal region of hGCHII interacts with α-phosphate of GTP. We propose that His-190 may play a role in the hydrolysis of pyrophosphate from GTP and in releasing the product, DARP. In summary, we demonstrate that the unstructured C-terminal residues of GCHII are important for its enzymatic activity and must be considered during rational drug designing. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Savita Yadav
- CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Ranajit Nivrutti Shinde
- CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Suruchi Singh
- CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Subramanian Karthikeyan
- CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Balvinder Singh
- CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
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20
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Jamalkandi SA, Kouhsar M, Salimian J, Ahmadi A. The identification of co-expressed gene modules in Streptococcus pneumonia from colonization to infection to predict novel potential virulence genes. BMC Microbiol 2020; 20:376. [PMID: 33334315 PMCID: PMC7745498 DOI: 10.1186/s12866-020-02059-0] [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: 06/25/2020] [Accepted: 12/02/2020] [Indexed: 11/14/2022] Open
Abstract
Background Streptococcus pneumonia (pneumococcus) is a human bacterial pathogen causing a range of mild to severe infections. The complicated transcriptome patterns of pneumococci during the colonization to infection process in the human body are usually determined by measuring the expression of essential virulence genes and the comparison of pathogenic with non-pathogenic bacteria through microarray analyses. As systems biology studies have demonstrated, critical co-expressing modules and genes may serve as key players in biological processes. Generally, Sample Progression Discovery (SPD) is a computational approach traditionally used to decipher biological progression trends and their corresponding gene modules (clusters) in different clinical samples underlying a microarray dataset. The present study aimed to investigate the bacterial gene expression pattern from colonization to severe infection periods (specimens isolated from the nasopharynx, lung, blood, and brain) to find new genes/gene modules associated with the infection progression. This strategy may lead to finding novel gene candidates for vaccines or drug design. Results The results included essential genes whose expression patterns varied in different bacterial conditions and have not been investigated in similar studies. Conclusions In conclusion, the SPD algorithm, along with differentially expressed genes detection, can offer new ways of discovering new therapeutic or vaccine targeted gene products. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-020-02059-0.
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Affiliation(s)
- Sadegh Azimzadeh Jamalkandi
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Morteza Kouhsar
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Jafar Salimian
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ali Ahmadi
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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21
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Molecular Elucidation of Riboflavin Production and Regulation in Candida albicans, toward a Novel Antifungal Drug Target. mSphere 2020; 5:5/4/e00714-20. [PMID: 32759338 PMCID: PMC7407072 DOI: 10.1128/msphere.00714-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Candida albicans is an important fungal pathogen causing common superficial infections as well as invasive diseases with an extremely high morbidity and mortality. Antifungal therapies are limited in efficiency and availability. In this research, we describe the regulation of riboflavin production in C. albicans. Since riboflavin biosynthesis is essential to this organism, we can appreciate that targeting it would be a promising new strategy to combat these fungal infections. We provide evidence that one particular enzyme in the production process, CaRib1, would be most promising as an antifungal drug target, as it plays a central role in regulation and proves to be essential in a mouse model of systemic infection. Candida albicans is a major cause of fungal infections, both superficial and invasive. The economic costs as well as consequences for patient welfare are substantial. Only a few treatment options are available due to the high resemblance between fungal targets and host molecules, as both are eukaryotes. Riboflavin is a yellow pigment, also termed vitamin B2. Unlike animals, fungi can synthesize this essential component themselves, thereby leading us to appreciate that targeting riboflavin production is a promising novel strategy against fungal infections. Here, we report that the GTP cyclohydrolase encoded by C. albicansRIB1 (CaRIB1) is essential and rate-limiting for production of riboflavin in the fungal pathogen. We confirm the high potential of CaRib1 as an antifungal drug target, as its deletion completely impairs in vivo infectibility by C. albicans in model systems. Furthermore, the stimulating effect of iron deprivation and PKA activation on riboflavin production seems to involve CaRib1 and the upstream transcription factor CaSef1. Gathering insights in the synthesis mechanism of riboflavin in pathogenic fungi, like C. albicans, will allow us to design a novel strategy and specifically target this process to combat fungal infections. IMPORTANCECandida albicans is an important fungal pathogen causing common superficial infections as well as invasive diseases with an extremely high morbidity and mortality. Antifungal therapies are limited in efficiency and availability. In this research, we describe the regulation of riboflavin production in C. albicans. Since riboflavin biosynthesis is essential to this organism, we can appreciate that targeting it would be a promising new strategy to combat these fungal infections. We provide evidence that one particular enzyme in the production process, CaRib1, would be most promising as an antifungal drug target, as it plays a central role in regulation and proves to be essential in a mouse model of systemic infection.
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22
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Serer MI, Carrica MDC, Trappe J, López Romero S, Bonomi HR, Klinke S, Cerutti ML, Goldbaum FA. A high-throughput screening for inhibitors of riboflavin synthase identifies novel antimicrobial compounds to treat brucellosis. FEBS J 2019; 286:2522-2535. [PMID: 30927485 DOI: 10.1111/febs.14829] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/26/2019] [Accepted: 03/29/2019] [Indexed: 10/27/2022]
Abstract
Brucella spp. are pathogenic intracellular Gram-negative bacteria adapted to life within cells of several mammals, including humans. These bacteria are the causative agent of brucellosis, one of the zoonotic infections with the highest incidence in the world and for which a human vaccine is still unavailable. Current therapeutic treatments against brucellosis are based on the combination of two or more antibiotics for prolonged periods, which may lead to antibiotic resistance in the population. Riboflavin (vitamin B2) is biosynthesized by microorganisms and plants but mammals, including humans, must obtain it from dietary sources. Owing to the absence of the riboflavin biosynthetic enzymes in animals, this pathway is nowadays regarded as a rich resource of targets for the development of new antimicrobial agents. In this work, we describe a high-throughput screening approach to identify inhibitors of the enzymatic activity of riboflavin synthase, the last enzyme in this pathway. We also provide evidence for their subsequent validation as potential drug candidates in an in vitro brucellosis infection model. From an initial set of 44 000 highly diverse low molecular weight compounds with drug-like properties, we were able to identify ten molecules with 50% inhibitory concentrations in the low micromolar range. Further Brucella culture and intramacrophagic replication experiments showed that the most effective bactericidal compounds share a 2-Phenylamidazo[2,1-b][1,3]benzothiazole chemical scaffold. Altogether, these findings set up the basis for the subsequent lead optimization process and represent a promising advancement in the pursuit of novel and effective antimicrobial compounds against brucellosis.
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Affiliation(s)
- María Inés Serer
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | | | - Jörg Trappe
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires, Argentina
| | - María Laura Cerutti
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires, Argentina
| | - Fernando Alberto Goldbaum
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires, Argentina
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23
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Meir Z, Osherov N. Vitamin Biosynthesis as an Antifungal Target. J Fungi (Basel) 2018; 4:E72. [PMID: 29914189 PMCID: PMC6023522 DOI: 10.3390/jof4020072] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 12/18/2022] Open
Abstract
The large increase in the population of immunosuppressed patients, coupled with the limited efficacy of existing antifungals and rising resistance toward them, have dramatically highlighted the need to develop novel drugs for the treatment of invasive fungal infections. An attractive possibility is the identification of possible drug targets within essential fungal metabolic pathways not shared with humans. Here, we review the vitamin biosynthetic pathways (vitamins A⁻E, K) as candidates for the development of antifungals. We present a set of ranking criteria that identify the vitamin B2 (riboflavin), B5 (pantothenic acid), and B9 (folate) biosynthesis pathways as being particularly rich in new antifungal targets. We propose that recent scientific advances in the fields of drug design and fungal genomics have developed sufficiently to merit a renewed look at these pathways as promising sources for the development of novel classes of antifungals.
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Affiliation(s)
- Zohar Meir
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
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24
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Chen SC, Yen TM, Chang TH, Liaw SH. Evolution of archaeal Rib7 and eubacterial RibG reductases in riboflavin biosynthesis: Substrate specificity and cofactor preference. Biochem Biophys Res Commun 2018; 503:195-201. [PMID: 29864427 DOI: 10.1016/j.bbrc.2018.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/01/2018] [Indexed: 10/14/2022]
Abstract
Archaeal/fungal Rib7 and eubacterial RibG possess a reductase domain for ribosyl reduction in the second and third steps, respectively, of riboflavin biosynthesis. These enzymes are specific for an amino and a carbonyl group of the pyrimidine ring, respectively. Here, several crystal structures of Methanosarcina mazei Rib7 are reported at 2.27-1.95 Å resolution, which are the first archaeal dimeric Rib7 structures. Mutational analysis displayed that no detectable activity was observed for the Bacillus subtilis RibG K151A, K151D, and K151E mutants, and the M. mazei Rib7 D33N, D33K, and E156Q variants, while 0.1-0.6% of the activity was detected for the M. mazei Rib7 N9A, S29A, D33A, and D57N variants. Our results suggest that Lys151 in B. subtilis RibG, while Asp33 together with Arg36 in M. mazei Rib7, ensure the specific substrate recognition. Unexpectedly, an endogenous NADPH cofactor is observed in M. mazei Rib7, in which the 2'-phosphate group interacts with Ser88, and Arg91. Replacement of Ser88 with glutamate eliminates the endogenous NADPH binding and switches preference to NADH. The lower melting temperature of ∼10 °C for the S88E and R91A mutants suggests that nature had evolved a tightly bound NADPH to greatly enhance the structural stability of archaeal Rib7.
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Affiliation(s)
- Sheng-Chia Chen
- Structural Biology Program, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei, 11221, Taiwan
| | - Te-Ming Yen
- Structural Biology Program, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei, 11221, Taiwan; Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei, 11221, Taiwan
| | - Ting-Hao Chang
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei, 11221, Taiwan
| | - Shwu-Huey Liaw
- Structural Biology Program, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei, 11221, Taiwan; Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei, 11221, Taiwan; Department of Medical Research and Education, Taipei Veterans General Hospital, No. 201, Sec. 2, Shipai Road, Beitou District, Taipei, 11217, Taiwan.
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25
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Dietl AM, Meir Z, Shadkchan Y, Osherov N, Haas H. Riboflavin and pantothenic acid biosynthesis are crucial for iron homeostasis and virulence in the pathogenic mold Aspergillus fumigatus. Virulence 2018; 9:1036-1049. [PMID: 30052132 PMCID: PMC6068542 DOI: 10.1080/21505594.2018.1482181] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Aspergillus fumigatus is the most prevalent airborne fungal pathogen, causing invasive fungal infections mainly in immunosuppressed individuals. Death rates from invasive aspergillosis remain high because of limited treatment options and increasing antifungal resistance. The aim of this study was to identify key fungal-specific genes participating in vitamin B biosynthesis in A. fumigatus. Because these genes are absent in humans they can serve as possible novel targets for antifungal drug development. METHODS By sequence homology we identified, deleted and analysed four key A. fumigatus genes (riboB, panA, pyroA, thiB) involved respectively in the biosynthesis of riboflavin (vitamin B2), pantothenic acid (vitamin B5), pyridoxine (vitamin B6) and thiamine (vitamin B1). RESULTS Deletion of riboB, panA, pyroA or thiB resulted in respective vitamin auxotrophy. Lack of riboflavin and pantothenic acid biosynthesis perturbed many cellular processes including iron homeostasis. Virulence in murine pulmonary and systemic models of infection was severely attenuated following deletion of riboB and panA, strongly reduced after pyroA deletion and weakly attenuated after thiB deletion. CONCLUSIONS This study reveals the biosynthetic pathways of the vitamins riboflavin and pantothenic acid as attractive targets for novel antifungal therapy. Moreover, the virulence studies with auxotrophic mutants serve to identify the availability of nutrients to pathogens in host niches. ABBREVIATIONS BPS: bathophenanthrolinedisulfonate; BSA: bovine serum albumin; CFU: colony forming unit; -Fe: iron starvation; +Fe: iron sufficiency; hFe: high iron; NRPSs: nonribosomal peptide synthetases; PKSs: polyketide synthaseses; wt: wild type.
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Affiliation(s)
- Anna-Maria Dietl
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Zohar Meir
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Yona Shadkchan
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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26
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Krajewski SS, Isoz I, Johansson J. Antibacterial and antivirulence effect of 6-N-hydroxylaminopurine in Listeria monocytogenes. Nucleic Acids Res 2017; 45:1914-1924. [PMID: 28062853 PMCID: PMC5389569 DOI: 10.1093/nar/gkw1308] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 12/20/2016] [Indexed: 01/07/2023] Open
Abstract
The emerging development of antibiotic resistant bacteria calls for novel types of antibacterial agents. In this work we examined the putative antibacterial effect of purine analogs in Listeria monocytogenes. We show that, among several tested purine analogs, only 6-N-hydroxylaminopurine (6-N-HAP) reduces the viability of the Gram-positive pathogen Listeria monocytogenes. As in Bacillus subtilis, 6-N-HAP terminates expression at guanine riboswitches in L. monocytogenes hence preventing expression of their downstream genes. However, we show that the bacteriocidal effect of the compound was unlinked to the terminated expression at the guanine riboswitches. When further examining the antimicrobial effect, we observed that 6-N-HAP acts as a potent mutagen in L. monocytogenes, by increasing the mutation rate and inducing the SOS-response. Also, addition of 6-N-HAP decreased virulence gene expression by reducing both the levels and activity of the virulence regulator PrfA.
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Affiliation(s)
- Stefanie Sandra Krajewski
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), Umeå University, 90187 Umeå, Sweden
| | - Isabelle Isoz
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), Umeå University, 90187 Umeå, Sweden
| | - Jörgen Johansson
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), Umeå University, 90187 Umeå, Sweden
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27
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Molecular dynamics studies unravel role of conserved residues responsible for movement of ions into active site of DHBPS. Sci Rep 2017; 7:40452. [PMID: 28079168 PMCID: PMC5228156 DOI: 10.1038/srep40452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 12/07/2016] [Indexed: 11/08/2022] Open
Abstract
3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) catalyzes the conversion of D-ribulose 5-phosphate (Ru5P) to L-3,4-dihydroxy-2-butanone-4-phosphate in the presence of Mg2+. Although crystal structures of DHBPS in complex with Ru5P and non-catalytic metal ions have been reported, structure with Ru5P along with Mg2+ is still elusive. Therefore, mechanistic role played by Mg2+ in the structure of DHBPS is poorly understood. In this study, molecular dynamics simulations of DHBPS-Ru5P complex along with Mg2+ have shown entry of Mg2+ from bulk solvent into active site. Presence of Mg2+ in active site has constrained conformations of Ru5P and has reduced flexibility of loop-2. Formation of hydrogen bonds among Thr-108 and residues - Gly-109, Val-110, Ser-111, and Asp-114 are found to be critical for entry of Mg2+ into active site. Subsequent in silico mutations of residues, Thr-108 and Asp-114 have substantiated the importance of these interactions. Loop-4 of one monomer is being proposed to act as a “lid” covering the active site of other monomer. Further, the conserved nature of residues taking part in the transfer of Mg2+ suggests the same mechanism being present in DHBPS of other microorganisms. Thus, this study provides insights into the functioning of DHBPS that can be used for the designing of inhibitors.
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28
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Colameco S, Elliot MA. Non-coding RNAs as antibiotic targets. Biochem Pharmacol 2016; 133:29-42. [PMID: 28012959 DOI: 10.1016/j.bcp.2016.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/12/2016] [Indexed: 02/07/2023]
Abstract
Antibiotics inhibit a wide range of essential processes in the bacterial cell, including replication, transcription, translation and cell wall synthesis. In many instances, these antibiotics exert their effects through association with non-coding RNAs. This review highlights many classical antibiotic targets (e.g. rRNAs and the ribosome), explores a number of emerging targets (e.g. tRNAs, RNase P, riboswitches and small RNAs), and discusses the future directions and challenges associated with non-coding RNAs as antibiotic targets.
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Affiliation(s)
- Savannah Colameco
- Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Marie A Elliot
- Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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29
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Mehla K, Ramana J. Tapping into Salmonella typhimurium LT2 genome in a quest to explore its therapeutic arsenal: A metabolic network modeling approach. Biomed Pharmacother 2016; 86:57-66. [PMID: 27939520 DOI: 10.1016/j.biopha.2016.11.129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 11/24/2016] [Accepted: 11/27/2016] [Indexed: 01/17/2023] Open
Abstract
S. typhimurium, the classical broad-host-range serovar is a widely distributed cause of food-borne illness. Escalating antibiotic resistance and potential of conjugal transmission to other pathogens attributable to its broad spectrum host specificities have aided S. typhimurium to emerge as a global health threat. To keep pace with ever evolving bacterial defenses, there is dire need to restock the antibiotic pipeline. Genome scale metabolic reconstructions present immense possibilities to decipher physiological properties of an organism using constraint-based methods The systems-level approaches of genome scale metabolic networks interrogation open up new avenues of drug target identification against deadly infectious diseases. We performed flux balance analysis and minimization of metabolic adjustment studies of genome scale reconstruction model of S. typhimurium targeted at identifying large number of metabolites with a potential to be utilized as therapeutic drug targets. These constraint based approaches initially predict a set of genes indispensable to bacterial survival by performing gene knockout studies which are then prioritized through a multistep process. Metabolites involved in l-rhamnose biosynthesis, peptidoglycan biosynthesis, fatty acid biosynthesis, and folate biosynthesis pathways were prioritized as candidate drug targets. This study provides a general therapeutic approach which can be effectively applied to other pathogens as well.
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Affiliation(s)
- Kusum Mehla
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, PIN 173234 Himachal Pradesh, India
| | - Jayashree Ramana
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, PIN 173234 Himachal Pradesh, India.
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30
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Islam Z, Kumar A, Singh S, Salmon L, Karthikeyan S. Structural basis for competitive inhibition of 3,4-dihydroxy-2-butanone-4-phosphate synthase from Vibrio cholerae. J Biol Chem 2015; 290:11293-308. [PMID: 25792735 DOI: 10.1074/jbc.m114.611830] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Indexed: 11/06/2022] Open
Abstract
The riboflavin biosynthesis pathway has been shown to be essential in many pathogens and is absent in humans. Therefore, enzymes involved in riboflavin synthesis are considered as potential antibacterial drug targets. The enzyme 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) catalyzes one of the two committed steps in the riboflavin pathway and converts d-ribulose 5-phosphate (Ru5P) to l-3,4-dihydroxy-2-butanone 4-phosphate and formate. Moreover, DHBPS is shown to be indispensable for Mycobacterium, Salmonella, and Helicobacter species. Despite the essentiality of this enzyme in bacteria, no inhibitor has been identified hitherto. Here, we describe kinetic and crystal structure characterization of DHBPS from Vibrio cholerae (vDHBPS) with a competitive inhibitor 4-phospho-d-erythronohydroxamic acid (4PEH) at 1.86-Å resolution. In addition, we also report the structural characterization of vDHBPS in its apo form and in complex with its substrate and substrate plus metal ions at 1.96-, 1.59-, and 2.04-Å resolution, respectively. Comparison of these crystal structures suggests that 4PEH inhibits the catalytic activity of DHBPS as it is unable to form a proposed intermediate that is crucial for DHBPS activity. Furthermore, vDHBPS structures complexed with substrate and metal ions reveal that, unlike Candida albicans, binding of substrate to vDHBPS induces a conformational change from an open to closed conformation. Interestingly, the position of second metal ion, which is different from that of Methanococcus jannaschii, strongly supports an active role in the catalytic mechanism. Thus, the kinetic and structural characterization of vDHBPS reveals the molecular mechanism of inhibition shown by 4PEH and that it can be explored further for designing novel antibiotics.
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Affiliation(s)
- Zeyaul Islam
- From the CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160 036, India and
| | - Adarsh Kumar
- From the CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160 036, India and
| | - Suruchi Singh
- From the CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160 036, India and
| | - Laurent Salmon
- Laboratoire de Chimie Bioorganique et Bioinorganique, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud, CNRS UMR8182, F-91405 Orsay, France
| | - Subramanian Karthikeyan
- From the CSIR-Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Sector 39-A, Chandigarh 160 036, India and
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31
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Kuppuraj G, Kruise D, Yura K. Conformational behavior of flavin adenine dinucleotide: conserved stereochemistry in bound and free states. J Phys Chem B 2014; 118:13486-97. [PMID: 25389798 DOI: 10.1021/jp507629n] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Metabolic enzymes utilize the cofactor flavin adenine dinucleotide (FAD) to catalyze essential biochemical reactions. Because these enzymes have been implicated in disease pathways, it will be necessary to target them via FAD-based structural analogues that can either activate/inhibit the enzymatic activity. To achieve this, it is important to explore the conformational space of FAD in the enzyme-bound and free states. Herein, we analyze X-ray crystallographic data of the enzyme-bound FAD conformations and sample conformations of the molecule in explicit water by molecular dynamics (MD) simulations. Enzyme-bound FAD conformations segregate into five distinct groups based on dihedral angle principal component analysis (PCA). A notable feature in the bound FADs is that the adenine base and isoalloxazine ring are oppositely oriented relative to the pyrophosphate axis characterized by near trans hypothetical dihedral angle "δV" values. Not surprisingly, MD simulations in water show final compact but not perfectly stacked ring structures in FAD. Simulation data did not reveal noticeable changes in overall conformational dynamics of the dinucleotide in reduced and oxidized forms and in the presence and/or absence of ions. During unfolding-folding dynamics, the riboflavin moiety is more flexible than the adenosine monophosphate group in the molecule. Conversely, the isoalloxazine ring is more stable than the variable adenine base. The pyrophosphate group depicts an unusually highly organized fluctuation illustrated by its dihedral angle distribution. Conformations sampled from enzymes and MD are quantified. The extent to which the protein shifts the distribution from the unbound state is discussed in terms of prevalent FAD shapes and dihedral angle population.
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Affiliation(s)
- Gopi Kuppuraj
- Center for Informational Biology, Ochanomizu University , 2-1-1 Otsuka, Bunkyo, Tokyo 112-8610, Japan
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32
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Paulus B, Illarionov B, Nohr D, Roellinger G, Kacprzak S, Fischer M, Weber S, Bacher A, Schleicher E. One Protein, Two Chromophores: Comparative Spectroscopic Characterization of 6,7-Dimethyl-8-ribityllumazine and Riboflavin Bound to Lumazine Protein. J Phys Chem B 2014; 118:13092-105. [DOI: 10.1021/jp507618f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Bernd Paulus
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Boris Illarionov
- Institute for Biochemistry & Food Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Daniel Nohr
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Guillaume Roellinger
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Sylwia Kacprzak
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Markus Fischer
- Institute for Biochemistry & Food Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
| | - Stefan Weber
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
| | - Adelbert Bacher
- Institute for Biochemistry & Food Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany
- Chemistry
Department, Technical University Munich, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Erik Schleicher
- Institute
of Physical Chemistry, Albert-Ludwigs-University Freiburg, Albertstrasse
21, 79104 Freiburg, Germany
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33
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Differential protein accumulations in isolates of the strawberry wilt pathogen Fusarium oxysporum f. sp. fragariae differing in virulence. J Proteomics 2014; 108:223-37. [PMID: 24907490 DOI: 10.1016/j.jprot.2014.05.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 05/25/2014] [Accepted: 05/27/2014] [Indexed: 12/13/2022]
Abstract
UNLABELLED This study was conducted to define differences in Fusarium oxysporum f. sp. fragariae (Fof) isolates with different virulence efficiency to strawberry at the proteome level, in combination with their differences in mycelial growth, conidial production and germination. Comparative proteome analyses revealed substantial differences in mycelial proteomes between Fof isolates, where the 54 differentially accumulated protein spots were consistently over-accumulated or exclusively in the highly virulent isolate. These protein spots were identified through MALDI-TOF/TOF mass spectrometry analyses, and the identified proteins were mainly related to primary and protein metabolism, antioxidation, electron transport, cell cycle and transcription based on their putative functions. Proteins of great potential as Fof virulence factors were those involved in ubiquitin/proteasome-mediated protein degradation and reactive oxygen species detoxification; the hydrolysis-related protein haloacid dehalogenase superfamily hydrolase; 3,4-dihydroxy-2-butanone 4-phosphate synthase associated with riboflavin biosynthesis; and those exclusive to the highly virulent isolate. In addition, post-translational modifications may also make an important contribution to Fof virulence. BIOLOGICAL SIGNIFICANCE F. oxysporum f. sp. fragariae (Fof), the causal agent of Fusarium wilt in strawberry, is a serious threat to commercial strawberry production worldwide. However, factors and mechanisms contributing to Fof virulence remained unknown. This study provides knowledge of the molecular basis for the differential expression of virulence in Fof, allowing new possibilities towards developing alternative and more effective strategies to manage Fusarium wilt.
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Fallon AM, Baldridge GD, Carroll EM, Kurtz CM. Depletion of host cell riboflavin reduces Wolbachia levels in cultured mosquito cells. In Vitro Cell Dev Biol Anim 2014; 50:707-13. [PMID: 24789726 DOI: 10.1007/s11626-014-9758-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/07/2014] [Indexed: 02/03/2023]
Abstract
Wolbachia is an obligate intracellular alphaproteobacterium that occurs in arthropod and nematode hosts. Wolbachia presumably provides a fitness benefit to its hosts, but the basis for its retention and spread in host populations remains unclear. Wolbachia genomes retain biosynthetic pathways for some vitamins, and the possibility that these vitamins benefit host cells provides a potential means of selecting for Wolbachia-infected cell lines. To explore whether riboflavin produced by Wolbachia is available to its host cell, we established that growth of uninfected C7-10 mosquito cells decreases in riboflavin-depleted culture medium. A well-studied inhibitor of riboflavin uptake, lumiflavin, further inhibits growth of uninfected C7-10 cells with an LC50 of approximately 12 μg/ml. Growth of C/wStr1 mosquito cells, infected with Wolbachia from the planthopper, Laodelphax striatellus, was enhanced in medium containing low levels of lumiflavin, but Wolbachia levels decreased. Lumiflavin-enhanced growth thus resembled the improved growth that accompanies treatment with antibiotics that deplete Wolbachia, rather than a metabolic advantage provided by the Wolbachia infection. We used the polymerase chain reaction to validate the decrease in Wolbachia abundance and evaluated our results in the context of a proteomic analysis in which we detected nearly 800 wStr proteins. Our data indicate that Wolbachia converts riboflavin to FMN and FAD for its own metabolic needs, and does not provide a source of riboflavin for its host cell.
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Affiliation(s)
- Ann M Fallon
- Department of Entomology, University of Minnesota, 1980 Folwell Ave., St. Paul, MN, 55108, USA,
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Serer MI, Bonomi HR, Guimarães BG, Rossi RC, Goldbaum FA, Klinke S. Crystallographic and kinetic study of riboflavin synthase from Brucella abortus, a chemotherapeutic target with an enhanced intrinsic flexibility. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:1419-34. [PMID: 24816110 PMCID: PMC4014124 DOI: 10.1107/s1399004714005161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/06/2014] [Indexed: 11/11/2022]
Abstract
Riboflavin synthase (RS) catalyzes the last step of riboflavin biosynthesis in microorganisms and plants, which corresponds to the dismutation of two molecules of 6,7-dimethyl-8-ribityllumazine to yield one molecule of riboflavin and one molecule of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione. Owing to the absence of this enzyme in animals and the fact that most pathogenic bacteria show a strict dependence on riboflavin biosynthesis, RS has been proposed as a potential target for antimicrobial drug development. Eubacterial, fungal and plant RSs assemble as homotrimers lacking C3 symmetry. Each monomer can bind two substrate molecules, yet there is only one active site for the whole enzyme, which is located at the interface between two neighbouring chains. This work reports the crystallographic structure of RS from the pathogenic bacterium Brucella abortus (the aetiological agent of the disease brucellosis) in its apo form, in complex with riboflavin and in complex with two different product analogues, being the first time that the structure of an intact RS trimer with bound ligands has been solved. These crystal models support the hypothesis of enhanced flexibility in the particle and also highlight the role of the ligands in assembling the unique active site. Kinetic and binding studies were also performed to complement these findings. The structural and biochemical information generated may be useful for the rational design of novel RS inhibitors with antimicrobial activity.
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Affiliation(s)
- María I. Serer
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Hernán R. Bonomi
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Beatriz G. Guimarães
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP 48, 91192 Gif-sur-Yvette CEDEX, France
| | - Rolando C. Rossi
- Instituto de Química y Fisicoquímica Biológicas y Departamento de Química Biológica, IQUIFIB–UBA–CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina
| | - Fernando A. Goldbaum
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
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Moll I, Fabbretti A, Brandi L, Gualerzi CO. Inhibitors Targeting Riboswitches and Ribozymes. Antibiotics (Basel) 2013. [DOI: 10.1002/9783527659685.ch13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Singh M, Kumar P, Yadav S, Gautam R, Sharma N, Karthikeyan S. The crystal structure reveals the molecular mechanism of bifunctional 3,4-dihydroxy-2-butanone 4-phosphate synthase/GTP cyclohydrolase II (Rv1415) fromMycobacterium tuberculosis. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1633-44. [DOI: 10.1107/s0907444913011402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/26/2013] [Indexed: 11/10/2022]
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Dawson A, Trumper P, Chrysostomou G, Hunter WN. Structure of diaminohydroxyphosphoribosylaminopyrimidine deaminase/5-amino-6-(5-phosphoribosylamino)uracil reductase from Acinetobacter baumannii. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:611-7. [PMID: 23722836 PMCID: PMC3668577 DOI: 10.1107/s174430911301292x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/11/2013] [Indexed: 11/11/2022]
Abstract
The bifunctional diaminohydroxyphosphoribosylaminopyrimidine deaminase/5-amino-6-(5-phosphoribosylamino)uracil reductase (RibD) represents a potential antibacterial drug target. The structure of recombinant Acinetobacter baumannii RibD is reported in orthorhombic and tetragonal crystal forms at 2.2 and 2.0 Å resolution, respectively. Comparisons with orthologous structures in the Protein Data Bank indicated close similarities. The tetragonal crystal form was obtained in the presence of guanosine monophosphate, which surprisingly was observed to occupy the adenine-binding site of the reductase domain.
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Affiliation(s)
- Alice Dawson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Paul Trumper
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Georgios Chrysostomou
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - William N. Hunter
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
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Ladenstein R, Fischer M, Bacher A. The lumazine synthase/riboflavin synthase complex: shapes and functions of a highly variable enzyme system. FEBS J 2013; 280:2537-63. [PMID: 23551830 DOI: 10.1111/febs.12255] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 11/30/2022]
Abstract
The xylene ring of riboflavin (vitamin B2 ) is assembled from two molecules of 3,4-dihydroxy-2-butanone 4-phosphate by a mechanistically complex process that is jointly catalyzed by lumazine synthase and riboflavin synthase. In Bacillaceae, these enzymes form a structurally unique complex comprising an icosahedral shell of 60 lumazine synthase subunits and a core of three riboflavin synthase subunits, whereas many other bacteria have empty lumazine synthase capsids, fungi, Archaea and some eubacteria have pentameric lumazine synthases, and the riboflavin synthases of Archaea are paralogs of lumazine synthase. The structures of the molecular ensembles have been studied in considerable detail by X-ray crystallography, X-ray small-angle scattering and electron microscopy. However, certain mechanistic aspects remain unknown. Surprisingly, the quaternary structure of the icosahedral β subunit capsids undergoes drastic changes, resulting in formation of large, quasi-spherical capsids; this process is modulated by sequence mutations. The occurrence of large shells consisting of 180 or more lumazine synthase subunits has recently generated interest for protein engineering topics, particularly the construction of encapsulation systems.
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Affiliation(s)
- Rudolf Ladenstein
- Department of Bioscience and Nutrition, Karolinska Institutet NOVUM, SE-14183 Huddinge, Sweden.
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Lv Z, Sun J, Liu Y. Structural and functional insights into Saccharomyces cerevisiae riboflavin biosynthesis reductase RIB7. PLoS One 2013; 8:e61249. [PMID: 23620735 PMCID: PMC3631187 DOI: 10.1371/journal.pone.0061249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 03/06/2013] [Indexed: 11/19/2022] Open
Abstract
Saccharomyces cerevisiae RIB7 (ScRIB7) is a potent target for anti-fungal agents because of its involvement in the riboflavin biosynthesis pathway as a NADPH-dependent reductase. However, the catalytic mechanism of riboflavin biosynthesis reductase (RBSRs) is controversial, and enzyme structure information is still lacking in eukaryotes. Here we report the crystal structure of Saccharomyces cerevisiae RIB7 at 2.10 Å resolution and its complex with NADPH at 2.35 Å resolution. ScRIB7 exists as a stable homodimer, and each subunit consists of nine central β-sheets flanked by five helices, resembling the structure of RIB7 homologues. A conserved G(76)-X-G(78)-Xn-G(181)-G(182) motif is present at the NADPH pyrophosphate group binding site. Activity assays confirmed the necessity of Thr79, Asp83, Glu180 and Gly182 for the activity of ScRIB7. Substrate preference of ScRIB7 was altered by mutating one residue (Thr35) to a Lysine, implying that ScRIB7 Thr35 and its corresponding residue, a lysine in bacteria, are important in substrate-specific recognition.
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Affiliation(s)
- Zongyang Lv
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Jian Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Yingfang Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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Chen SC, Shen CY, Yen TM, Yu HC, Chang TH, Lai WL, Liaw SH. Evolution of vitamin B2biosynthesis: eubacterial RibG and fungal Rib2 deaminases. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:227-36. [DOI: 10.1107/s0907444912044903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/30/2012] [Indexed: 12/27/2022]
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Chauviac FX, Bommer M, Yan J, Parkin G, Daviter T, Lowden P, Raven EL, Thalassinos K, Keep NH. Crystal structure of reduced MsAcg, a putative nitroreductase from Mycobacterium smegmatis and a close homologue of Mycobacterium tuberculosis Acg. J Biol Chem 2012; 287:44372-83. [PMID: 23148223 DOI: 10.1074/jbc.m112.406264] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This paper presents the structure of MsAcg (MSMEG_5246), a Mycobacterium smegmatis homologue of Mycobacterium tuberculosis Acg (Rv2032) in its reduced form at 1.6 Å resolution using x-ray crystallography. Rv2032 is one of the most induced genes under the hypoxic model of tuberculosis dormancy. The Acg family turns out to be unusual flavin mononucleotide (FMN)-binding proteins that have probably arisen by gene duplication and fusion from a classical homodimeric nitroreductase such that the monomeric protein resembles a classical nitroreductase dimer but with one active site deleted and the other active site covered by a unique lid. The FMN cofactor is not reduced by either NADH or NADPH, but the chemically reduced enzyme is capable of reduction of nitro substrates, albeit at no kinetic advantage over free FMN. The reduced enzyme is rapidly oxidized by oxygen but without any evidence for a radical state commonly seen in oxygen-sensitive nitroreductases. The presence of the unique lid domain, the lack of reduction by NAD(P)H, and the slow rate of reaction of the chemically reduced protein raises a possible alternative function of Acg proteins in FMN storage or sequestration from other biochemical pathways as part of the bacteria's adaptation to a dormancy state.
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Affiliation(s)
- François-Xavier Chauviac
- Crystallography, Institute for Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, WC1E 7HX, United Kingdom
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Singh S, Gupta S, Singh B, Sharma SK, Gupta VK, Sharma GL. Proteomic characterization of Aspergillus fumigatus treated with an antifungal coumarin for identification of novel target molecules of key pathways. J Proteome Res 2012; 11:3259-68. [PMID: 22533410 DOI: 10.1021/pr300006j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A synthetic coumarin, N,N,N-triethyl-11-(4-methyl-2-oxo-2H-chromen-7-yloxy)-11-oxoundecan-1-aminium bromide (SCD-1), having potent activity against pathogenic Aspergilli (MIC90 15.62 μg/mL), was investigated to identify its molecular targets in the pathogen. The proteome of Aspergillus fumigatus was developed after treatment with sublethal doses of compound and analyzed. The results demonstrated 143 differentially expressed proteins on treatment with SCD-1. The expression of four proteins, namely cell division control protein, ubiquitin-like activating enzyme, vacuolar ATP synthase catalytic subunit A, and UTP-glucose-1-phosphate uridylyltransferase of A. fumigatus, was completely inhibited, whereas there were 13 newly expressed and 96 overexpressed proteins, mainly belonging to stress pathway. The treatment of A. fumigatus with SCD-1 also led to attenuation of proteins involved in cell replication and other important biosynthetic processes, including riboflavin biosynthesis, which has been pathogen-specific. In addition to key enzymatic players and antioxidants, nine hypothetical proteins were also identified, seven of which have been novel, being described for the first time. As no cellular functions have yet been described for these hypothetical proteins, their alteration in response to SCD-1 provides significant information about their putative roles in pathogen defense.
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Affiliation(s)
- Seema Singh
- Division of Diagnostics and Biochemistry, CSIR-Institute of Genomics and Integrative Biology , University Campus, Mall Road, Delhi-110007, India
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Abbas CA, Sibirny AA. Genetic control of biosynthesis and transport of riboflavin and flavin nucleotides and construction of robust biotechnological producers. Microbiol Mol Biol Rev 2011; 75:321-60. [PMID: 21646432 PMCID: PMC3122625 DOI: 10.1128/mmbr.00030-10] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Riboflavin [7,8-dimethyl-10-(1'-d-ribityl)isoalloxazine, vitamin B₂] is an obligatory component of human and animal diets, as it serves as the precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which are involved in oxidative metabolism and other processes. Commercially produced riboflavin is used in agriculture, medicine, and the food industry. Riboflavin synthesis starts from GTP and ribulose-5-phosphate and proceeds through pyrimidine and pteridine intermediates. Flavin nucleotides are synthesized in two consecutive reactions from riboflavin. Some microorganisms and all animal cells are capable of riboflavin uptake, whereas many microorganisms have distinct systems for riboflavin excretion to the medium. Regulation of riboflavin synthesis in bacteria occurs by repression at the transcriptional level by flavin mononucleotide, which binds to nascent noncoding mRNA and blocks further transcription (named the riboswitch). In flavinogenic molds, riboflavin overproduction starts at the stationary phase and is accompanied by derepression of enzymes involved in riboflavin synthesis, sporulation, and mycelial lysis. In flavinogenic yeasts, transcriptional repression of riboflavin synthesis is exerted by iron ions and not by flavins. The putative transcription factor encoded by SEF1 is somehow involved in this regulation. Most commercial riboflavin is currently produced or was produced earlier by microbial synthesis using special selected strains of Bacillus subtilis, Ashbya gossypii, and Candida famata. Whereas earlier RF overproducers were isolated by classical selection, current producers of riboflavin and flavin nucleotides have been developed using modern approaches of metabolic engineering that involve overexpression of structural and regulatory genes of the RF biosynthetic pathway as well as genes involved in the overproduction of the purine precursor of riboflavin, GTP.
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Affiliation(s)
| | - Andriy A. Sibirny
- Institute of Cell Biology, NAS of Ukraine, Lviv 79005, Ukraine
- University of Rzeszow, Rzeszow 35-601, Poland
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