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Chengalroyen MD, Mehaffy C, Lucas M, Bauer N, Raphela ML, Oketade N, Warner DF, Lewinsohn DA, Lewinsohn DM, Dobos KM, Mizrahi V. Modulation of riboflavin biosynthesis and utilization in mycobacteria. Microbiol Spectr 2024; 12:e0320723. [PMID: 38916330 PMCID: PMC11302143 DOI: 10.1128/spectrum.03207-23] [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: 09/06/2023] [Accepted: 05/17/2024] [Indexed: 06/26/2024] Open
Abstract
Riboflavin (vitamin B2) is the precursor of the flavin coenzymes, FAD and FMN, which play a central role in cellular redox metabolism. While humans must obtain riboflavin from dietary sources, certain microbes, including Mycobacterium tuberculosis (Mtb), can biosynthesize riboflavin de novo. Riboflavin precursors have also been implicated in the activation of mucosal-associated invariant T (MAIT) cells which recognize metabolites derived from the riboflavin biosynthesis pathway complexed to the MHC-I-like molecule, MR1. To investigate the biosynthesis and function of riboflavin and its pathway intermediates in mycobacterial metabolism and physiology, we constructed conditional knockdowns (hypomorphs) in riboflavin biosynthesis and utilization genes in Mycobacterium smegmatis (Msm) and Mtb by inducible CRISPR interference. Using this comprehensive panel of hypomorphs, we analyzed the impact of gene silencing on viability, on the transcription of (other) riboflavin pathway genes, on the levels of the pathway proteins, and on riboflavin itself. Our results revealed that (i) despite lacking a canonical transporter, both Msm and Mtb assimilate exogenous riboflavin when supplied at high concentration; (ii) there is functional redundancy in lumazine synthase activity in Msm; (iii) silencing of ribA2 or ribF is profoundly bactericidal in Mtb; and (iv) in Msm, ribA2 silencing results in concomitant knockdown of other pathway genes coupled with RibA2 and riboflavin depletion and is also bactericidal. In addition to their use in genetic validation of potential drug targets for tuberculosis, this collection of hypomorphs provides a useful resource for future studies investigating the role of pathway intermediates in MAIT cell recognition of mycobacteria. IMPORTANCE The pathway for biosynthesis and utilization of riboflavin, precursor of the essential coenzymes, FMN and FAD, is of particular interest in the flavin-rich pathogen, Mycobacterium tuberculosis (Mtb), for two important reasons: (i) the pathway includes potential tuberculosis (TB) drug targets and (ii) intermediates from the riboflavin biosynthesis pathway provide ligands for mucosal-associated invariant T (MAIT) cells, which have been implicated in TB pathogenesis. However, the riboflavin pathway is poorly understood in mycobacteria, which lack canonical mechanisms to transport this vitamin and to regulate flavin coenzyme homeostasis. By conditionally disrupting each step of the pathway and assessing the impact on mycobacterial viability and on the levels of the pathway proteins as well as riboflavin, our work provides genetic validation of the riboflavin pathway as a target for TB drug discovery and offers a resource for further exploring the association between riboflavin biosynthesis, MAIT cell activation, and TB infection and disease.
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Affiliation(s)
- Melissa D. Chengalroyen
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Carolina Mehaffy
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Megan Lucas
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Niel Bauer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Mabule L. Raphela
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Nurudeen Oketade
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Digby F. Warner
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
| | | | - David M. Lewinsohn
- Oregon Health and Science University, Portland, Oregon, USA
- Portland VA Medical Center, Portland, Oregon, USA
| | - Karen M. Dobos
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Valerie Mizrahi
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
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2
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Mirsalami SM, Mirsalami M. Evolutionary adaptation in the laboratory and the process of retrograde engineering augment autotrophic proliferation in Saccharomyces cerevisiae. Biochem Eng J 2024; 205:109278. [DOI: 10.1016/j.bej.2024.109278] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2024]
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3
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Faustino M, Lourenço T, Strobbe S, Cao D, Fonseca A, Rocha I, Van Der Straeten D, Oliveira MM. Mathematical kinetic modelling followed by in vitro and in vivo assays reveal the bifunctional rice GTPCHII/DHBPS enzymes and demonstrate the key roles of OsRibA proteins in the vitamin B2 pathway. BMC PLANT BIOLOGY 2024; 24:220. [PMID: 38532321 DOI: 10.1186/s12870-024-04878-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/03/2024] [Indexed: 03/28/2024]
Abstract
BACKGROUND Riboflavin is the precursor of several cofactors essential for normal physical and cognitive development, but only plants and some microorganisms can produce it. Humans thus rely on their dietary intake, which at a global level is mainly constituted by cereals (> 50%). Understanding the riboflavin biosynthesis players is key for advancing our knowledge on this essential pathway and can hold promise for biofortification strategies in major crop species. In some bacteria and in Arabidopsis, it is known that RibA1 is a bifunctional protein with distinct GTP cyclohydrolase II (GTPCHII) and 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) domains. Arabidopsis harbors three RibA isoforms, but only one retained its bifunctionality. In rice, however, the identification and characterization of RibA has not yet been described. RESULTS Through mathematical kinetic modeling, we identified RibA as the rate-limiting step of riboflavin pathway and by bioinformatic analysis we confirmed that rice RibA proteins carry both domains, DHBPS and GTPCHII. Phylogenetic analysis revealed that OsRibA isoforms 1 and 2 are similar to Arabidopsis bifunctional RibA1. Heterologous expression of OsRibA1 completely restored the growth of the rib3∆ yeast mutant, lacking DHBPS expression, while causing a 60% growth improvement of the rib1∆ mutant, lacking GTPCHII activity. Regarding OsRibA2, its heterologous expression fully complemented GTPCHII activity, and improved rib3∆ growth by 30%. In vitro activity assays confirmed that both OsRibA1 and OsRibA2 proteins carry GTPCHII/DHBPS activities, but that OsRibA1 has higher DHBPS activity. The overexpression of OsRibA1 in rice callus resulted in a 28% increase in riboflavin content. CONCLUSIONS Our study elucidates the critical role of RibA in rice riboflavin biosynthesis pathway, establishing it as the rate-limiting step in the pathway. By identifying and characterizing OsRibA1 and OsRibA2, showcasing their GTPCHII and DHBPS activities, we have advanced the understanding of riboflavin biosynthesis in this staple crop. We further demonstrated that OsRibA1 overexpression in rice callus increases its riboflavin content, providing supporting information for bioengineering efforts.
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Affiliation(s)
- Maria Faustino
- Laboratory of Plant Functional Genomics, Instituto de Tecnologia Química E Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, 2780-157, Portugal
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, Gent, B-9000, Belgium
| | - Tiago Lourenço
- Laboratory of Plant Functional Genomics, Instituto de Tecnologia Química E Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, 2780-157, Portugal
| | - Simon Strobbe
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, Gent, B-9000, Belgium
- University of Geneva, Quai E. Ansermet 30, Geneva, 1211, Switzerland
| | - Da Cao
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, Gent, B-9000, Belgium
| | - André Fonseca
- Laboratory of Systems and Synthetic Biology, Instituto de Tecnologia Química E Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, 2780-157, Portugal
| | - Isabel Rocha
- Laboratory of Systems and Synthetic Biology, Instituto de Tecnologia Química E Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, 2780-157, Portugal
| | - Dominique Van Der Straeten
- Laboratory of Functional Plant Biology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, Gent, B-9000, Belgium.
| | - M Margarida Oliveira
- Laboratory of Plant Functional Genomics, Instituto de Tecnologia Química E Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, 2780-157, Portugal.
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Zhou J, Xu S, Li H, Xi H, Cheng W, Yang C. A Ribulose-5-phosphate Shunt from the Calvin-Benson Cycle to Methylerythritol Phosphate Pathway for Enhancing Photosynthetic Terpenoid Production. ACS Synth Biol 2024; 13:876-887. [PMID: 38362836 DOI: 10.1021/acssynbio.3c00675] [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] [Indexed: 02/17/2024]
Abstract
Cyanobacteria are attractive hosts for photosynthetic terpenoid production, using CO2 as the sole carbon source. Although the methylerythritol phosphate (MEP) pathway is superior to the mevalonate pathway for cyanobacterial terpenoid synthesis, the first reaction of the MEP pathway, which is catalyzed by 1-deoxy-d-xylulose-5-phosphate (DXP) synthase, involves complex regulation and carbon loss. Here, we constructed a direct route linking ribulose-5-phosphate (Ru5P) in the Calvin-Benson (CB) cycle with DXP in the MEP pathway in a cyanobacterium to increase the terpenoid yield from CO2 and bypass the DXS-targeted regulations. By employing the adaptive laboratory evolution, we identified new RibB variants including RibB 90-92del with a high activity of synthesizing DXP from Ru5P. These RibB variants were introduced into Synechococcus elongatus, resulting in the significantly increased photosynthetic production of isopentenol. The 13C tracer experiments demonstrated a direct carbon flow from Ru5P in the CB cycle to the MEP pathway; thus, this direct route was denoted as the Ru5P shunt. The strain harboring the Ru5P shunt produced 105.2 mg L-1 of isopentenol with an average rate of 17.5 mg L-1 d-1 under continuous light conditions, which is higher than those ever reported for five-carbon alcohol production by photoautotrophic microorganisms. Utilization of the Ru5P shunt in cyanobacterial cells also improved the pinene production, which demonstrates that this shunt can be used to enhance the photosynthetic production of diverse terpenoids.
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Affiliation(s)
- Jie Zhou
- CAS-Key Laboratory of Synthetic Biology, Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Suxian Xu
- CAS-Key Laboratory of Synthetic Biology, Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hu Li
- CAS-Key Laboratory of Synthetic Biology, Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huachao Xi
- CAS-Key Laboratory of Synthetic Biology, Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenbo Cheng
- CAS-Key Laboratory of Synthetic Biology, Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, Key Laboratory of Plant Carbon Capture, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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Gnanagobal H, Cao T, Hossain A, Vasquez I, Chakraborty S, Chukwu-Osazuwa J, Boyce D, Espinoza MJ, García-Angulo VA, Santander J. Role of riboflavin biosynthesis gene duplication and transporter in Aeromonas salmonicida virulence in marine teleost fish. Virulence 2023; 14:2187025. [PMID: 36895132 PMCID: PMC10012899 DOI: 10.1080/21505594.2023.2187025] [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: 03/11/2023] Open
Abstract
Active flavins derived from riboflavin (vitamin B2) are essential for life. Bacteria biosynthesize riboflavin or scavenge it through uptake systems, and both mechanisms may be present. Because of riboflavin's critical importance, the redundancy of riboflavin biosynthetic pathway (RBP) genes might be present. Aeromonas salmonicida, the aetiological agent of furunculosis, is a pathogen of freshwater and marine fish, and its riboflavin pathways have not been studied. This study characterized the A. salmonicida riboflavin provision pathways. Homology search and transcriptional orchestration analysis showed that A. salmonicida has a main riboflavin biosynthetic operon that includes ribD, ribE1, ribBA, and ribH genes. Outside the main operon, putative duplicated genes ribA, ribB and ribE, and a ribN riboflavin importer encoding gene, were found. Monocistronic mRNA ribA, ribB and ribE2 encode for their corresponding functional riboflavin biosynthetic enzyme. While the product of ribBA conserved the RibB function, it lacked the RibA function. Likewise, ribN encodes a functional riboflavin importer. Transcriptomics analysis indicated that external riboflavin affected the expression of a relatively small number of genes, including a few involved in iron metabolism. ribB was downregulated in response to external riboflavin, suggesting negative feedback. Deletion of ribA, ribB and ribE1 showed that these genes are required for A. salmonicida riboflavin biosynthesis and virulence in Atlantic lumpfish (Cyclopterus lumpus). A. salmonicida riboflavin auxotrophic attenuated mutants conferred low protection to lumpfish against virulent A. salmonicida. Overall, A. salmonicida has multiple riboflavin endowment forms, and duplicated riboflavin provision genes are critical for A. salmonicida infection.
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Affiliation(s)
- Hajarooba Gnanagobal
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Trung Cao
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Ahmed Hossain
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Ignacio Vasquez
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Setu Chakraborty
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Joy Chukwu-Osazuwa
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Danny Boyce
- The Dr. Joe Brown Aquatic Research Building (JBARB), Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Canada
| | - María Jesus Espinoza
- Microbiology and Mycology Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Mycology Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Javier Santander
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
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Chengalroyen MD, Mehaffy C, Lucas M, Bauer N, Raphela ML, Oketade N, Warner DF, Lewinsohn DA, Lewinsohn DM, Dobos KM, Mizrahi V. Modulation of riboflavin biosynthesis and utilization in mycobacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555301. [PMID: 37693561 PMCID: PMC10491194 DOI: 10.1101/2023.08.30.555301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Riboflavin (vitamin B2) is the precursor of the flavin coenzymes, FAD and FMN, which play a central role in cellular redox metabolism. While humans must obtain riboflavin from dietary sources, certain microbes, including Mycobacterium tuberculosis (Mtb), can biosynthesize riboflavin de novo. Riboflavin precursors have also been implicated in the activation of mucosal-associated invariant T (MAIT) cells which recognize metabolites derived from the riboflavin biosynthesis pathway complexed to the MHC-I-like molecule, MR1. To investigate the biosynthesis and function of riboflavin and its pathway intermediates in mycobacterial metabolism, physiology and MAIT cell recognition, we constructed conditional knockdowns (hypomorphs) in riboflavin biosynthesis and utilization genes in Mycobacterium smegmatis (Msm) and Mtb by inducible CRISPR interference. Using this comprehensive panel of hypomorphs, we analyzed the impact of gene silencing on viability, on the transcription of (other) riboflavin pathway genes, on the levels of the pathway proteins and on riboflavin itself. Our results revealed that (i) despite lacking a canonical transporter, both Msm and Mtb assimilate exogenous riboflavin when supplied at high concentration; (ii) there is functional redundancy in lumazine synthase activity in Msm; (iii) silencing of ribA2 or ribF is profoundly bactericidal in Mtb; and (iv) in Msm, ribA2 silencing results in concomitant knockdown of other pathway genes coupled with RibA2 and riboflavin depletion and is also bactericidal. In addition to their use in genetic validation of potential drug targets for tuberculosis, this collection of hypomorphs provides a useful resource for investigating the role of pathway intermediates in MAIT cell recognition of mycobacteria.
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Affiliation(s)
- Melissa D. Chengalroyen
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
| | - Carolina Mehaffy
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Megan Lucas
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Niel Bauer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Mabule L. Raphela
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
| | - Nurudeen Oketade
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Digby F. Warner
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa
| | | | - David M. Lewinsohn
- Oregon Health and Science University, Oregon, USA
- Portland VA Medical Center, Oregon, USA
| | - Karen M. Dobos
- Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, USA
| | - Valerie Mizrahi
- Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa
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7
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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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8
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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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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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10
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Current Promising Therapeutic Targets for Aspergillosis Treatment. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.2.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillosis is a fungal disease caused by different species of Aspergillus. They live in soil,dust and decomposed material. Number of Aspergillus species found till now is about 300 and more are still to be identified. Only few Aspergillus species can cause human disease and the most common species for human infection is Aspergillus fumigatus, which is a ubiquitous airborne saprophytic fungus. Severity of the disease ranges from an allergic response to life-threatening generalized infection. They grow optimally at 37°C and can grow upto 50°C. The fungal conidia are being constantly inhaled by humans and animals everyday normally gets eliminated by innate immune mechanism. Due to increasing number of immunocompromised patients, severe and fatal Aspergillosis cases have augmented. Currently, available antifungal drug for the treatment of Aspergillosis act on these three molecular target are 14 alpha demethylase for Azoles, ergosterol for Polyene and β-1,3-glucan synthase for Echinocandin. These antifungal drug show high resistance problem and toxicity. So, it is high time to develop new drugs for treatment with reduced toxicity and drug resistant problem. Synthesis of essential amino acid is absent in human as they obtain it from their diet but fungi synthesis these amino acid. Thus, enzymes in this pathway acts as novel drug target. This article summarizes promising drug targets presents in different metabolic pathway of Aspergillus genome and discusses their molecular functions in detail. This review also list down the inhibitors of these novel target. We present a comprehensive review that will pave way for discovery and development of novel antifungals against these drug targets for Aspergillosis treatment.
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11
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Matern WM, Jenquin RL, Bader JS, Karakousis PC. Identifying the essential genes of Mycobacterium avium subsp. hominissuis with Tn-Seq using a rank-based filter procedure. Sci Rep 2020; 10:1095. [PMID: 31974396 PMCID: PMC6978383 DOI: 10.1038/s41598-020-57845-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 01/08/2020] [Indexed: 12/31/2022] Open
Abstract
Mycobacterium avium subsp. hominissuis (MAH) is increasingly recognized as a significant cause of morbidity, particularly in elderly patients or those with immune deficiency or underlying lung impairment. Disease due to MAH is particularly difficult to treat, often requiring years of antibiotic therapy. Identification of genes essential for MAH growth may lead to novel strategies for improving curative therapy. Here we have generated saturating genome-wide transposon mutant pools in a strain of MAH (MAC109) and developed a novel computational technique for classifying annotated genomic features based on the in vitro effect of transposon mutagenesis. Our findings may help guide future genetic and biochemical studies of MAH pathogenesis and aid in the identification of new drugs to improve the treatment of these serious infections.
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Affiliation(s)
- William M Matern
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Center for Tuberculosis Research, Division of Infectious Diseases, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Robert L Jenquin
- High-Throughput Biology Center, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Joel S Bader
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- High-Throughput Biology Center, Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | - Petros C Karakousis
- Center for Tuberculosis Research, Division of Infectious Diseases, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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12
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Engineering Pseudomonas putida for isoprenoid production by manipulating endogenous and shunt pathways supplying precursors. Microb Cell Fact 2019; 18:152. [PMID: 31500633 PMCID: PMC6734295 DOI: 10.1186/s12934-019-1204-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/03/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The soil bacterium Pseudomonas putida is a promising platform for the production of industrially valuable natural compounds. In the case of isoprenoids, the availability of biosynthetic precursors is a major limiting factor. In P. putida and most other bacteria, these precursors are produced from pyruvate and glyceraldehyde 3-phosphate by the methylerythritol 4-phosphate (MEP) pathway, whereas other bacteria synthesize the same precursors from acetyl-CoA using the unrelated mevalonate (MVA) pathway. RESULTS Here we explored different strategies to increase the supply of isoprenoid precursors in P. putida cells using lycopene as a read-out. Because we were not aiming at producing high isoprenoid titers but were primarily interested in finding ways to enhance the metabolic flux to isoprenoids, we engineered the well-characterized P. putida strain KT2440 to produce low but detectable levels of lycopene under conditions in which MEP pathway steps were not saturated. Then, we compared lycopene production in cells expressing the Myxococcus xanthus MVA pathway genes or endogenous MEP pathway genes (dxs, dxr, idi) under the control of IPTG-induced and stress-regulated promoters. We also tested a shunt pathway producing isoprenoid precursors from ribulose 5-phosphate using a mutant version of the Escherichia coli ribB gene. CONCLUSIONS The most successful combination led to a 50-fold increase in lycopene levels, indicating that P. putida can be successfully engineered to substantially increase the supply of metabolic substrates for the production of industrially valuable isoprenoids.
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Wang J, Lonergan ZR, Gonzalez-Gutierrez G, Nairn BL, Maxwell CN, Zhang Y, Andreini C, Karty JA, Chazin WJ, Trinidad JC, Skaar EP, Giedroc DP. Multi-metal Restriction by Calprotectin Impacts De Novo Flavin Biosynthesis in Acinetobacter baumannii. Cell Chem Biol 2019; 26:745-755.e7. [PMID: 30905682 PMCID: PMC6525019 DOI: 10.1016/j.chembiol.2019.02.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/20/2019] [Accepted: 02/18/2019] [Indexed: 02/07/2023]
Abstract
Calprotectin (CP) inhibits bacterial viability through extracellular chelation of transition metals. However, how CP influences general metabolism remains largely unexplored. We show here that CP restricts bioavailable Zn and Fe to the pathogen Acinetobacter baumannii, inducing an extensive multi-metal perturbation of cellular physiology. Proteomics reveals severe metal starvation, and a strain lacking the candidate ZnII metallochaperone ZigA possesses altered cellular abundance of multiple essential Zn-dependent enzymes and enzymes in de novo flavin biosynthesis. The ΔzigA strain exhibits decreased cellular flavin levels during metal starvation. Flavin mononucleotide provides regulation of this biosynthesis pathway, via a 3,4-dihydroxy-2-butanone 4-phosphate synthase (RibB) fusion protein, RibBX, and authentic RibB. We propose that RibBX ensures flavin sufficiency under CP-induced Fe limitation, allowing flavodoxins to substitute for Fe-ferredoxins as cell reductants. These studies elucidate adaptation to nutritional immunity and define an intersection between metallostasis and cellular metabolism in A. baumannii.
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Affiliation(s)
- Jiefei Wang
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Zachery R Lonergan
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Brittany L Nairn
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christina N Maxwell
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Yixiang Zhang
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Claudia Andreini
- Magnetic Resonance Centre (CERM), University of Florence, Florence, 50019 Sesto Fiorentino, Italy
| | - Jonathan A Karty
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Jonathan C Trinidad
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
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14
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Jacques B, Coinçon M, Sygusch J. Active site remodeling during the catalytic cycle in metal-dependent fructose-1,6-bisphosphate aldolases. J Biol Chem 2018; 293:7737-7753. [PMID: 29593097 PMCID: PMC5961046 DOI: 10.1074/jbc.ra117.001098] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/21/2018] [Indexed: 01/07/2023] Open
Abstract
Crystal structures of two bacterial metal (Zn2+)-dependent d-fructose-1,6-bisphosphate (FBP) aldolases in complex with substrate, analogues, and triose-P reaction products were determined to 1.5-2.0 Å resolution. The ligand complexes cryotrapped in native or mutant Helicobacter pylori aldolase crystals enabled a novel mechanistic description of FBP C3-C4 bond cleavage. The reaction mechanism uses active site remodeling during the catalytic cycle, implicating relocation of the Zn2+ cofactor that is mediated by conformational changes of active site loops. Substrate binding initiates conformational changes triggered upon P1 phosphate binding, which liberates the Zn2+-chelating His-180, allowing it to act as a general base for the proton abstraction at the FBP C4 hydroxyl group. A second zinc-chelating His-83 hydrogen bonds the substrate C4 hydroxyl group and assists cleavage by stabilizing the developing negative charge during proton abstraction. Cleavage is concerted with relocation of the metal cofactor from an interior to a surface-exposed site, thereby stabilizing the nascent enediolate form. Conserved residue Glu-142 is essential for protonation of the enediolate form prior to product release. A d-tagatose 1,6-bisphosphate enzymatic complex reveals how His-180-mediated proton abstraction controls stereospecificity of the cleavage reaction. Recognition and discrimination of the reaction products, dihydroxyacetone-P and d-glyceraldehyde 3-P, occurs via charged hydrogen bonds between hydroxyl groups of the triose-Ps and conserved residues, Asp-82 and Asp-255, respectively, and are crucial aspects of the enzyme's role in gluconeogenesis. Conformational changes in mobile loops β5-α7 and β6-α8 (containing catalytic residues Glu-142 and His-180, respectively) drive active site remodeling, enabling the relocation of the metal cofactor.
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Affiliation(s)
- Benoit Jacques
- From the Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Mathieu Coinçon
- From the Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Jurgen Sygusch
- From the Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada, To whom correspondence should be addressed:
Biochimie et Médecine moléculaire, Université de Montréal, CP 6128, Station Centre Ville, Montréal, Quebec H3C 3J7, Canada. Tel.:
514-343-2389; Fax:
514-343-6463; E-mail:
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15
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Sepúlveda-Cisternas I, Lozano Aguirre L, Fuentes Flores A, Vásquez Solis de Ovando I, García-Angulo VA. Transcriptomics reveals a cross-modulatory effect between riboflavin and iron and outlines responses to riboflavin biosynthesis and uptake in Vibrio cholerae. Sci Rep 2018; 8:3149. [PMID: 29453341 PMCID: PMC5816637 DOI: 10.1038/s41598-018-21302-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/31/2018] [Indexed: 12/19/2022] Open
Abstract
Vibrio cholerae, a pandemic diarrheagenic bacterium, is able to synthesize the essential vitamin riboflavin through the riboflavin biosynthetic pathway (RBP) and also to internalize it through the RibN importer. In bacteria, the way riboflavin biosynthesis and uptake functions correlate is unclear. To gain insights into the role of the riboflavin provision pathways in the physiology of V. cholerae, we analyzed the transcriptomics response to extracellular riboflavin and to deletions of ribD (RBP-deficient strain) or ribN. Many riboflavin-responsive genes were previously reported to belong to the iron regulon, including various iron uptake genes. Real time PCR analysis confirmed this effect and further documented that reciprocally, iron regulates RBP and ribN genes in a riboflavin-dependent way. A subset of genes were responding to both ribD and ribN deletions. However, in the subset of genes specifically affected in the ∆ribD strain, the functional terms protein folding and oxidation reduction process were enriched, as determined by a Gene Ontology analysis. In the gene subset specifically affected in the ∆ribN strain, the cytochrome complex assembly functional term was enriched. Results suggest that iron and riboflavin interrelate to regulate its respective provision genes and that both common and specific effects of biosynthesized and internalized riboflavin exist.
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Affiliation(s)
- Ignacio Sepúlveda-Cisternas
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Escuela de Biotecnología, Universidad Mayor, Campus Huechuraba, Santiago, Chile
| | - Luis Lozano Aguirre
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, campus Chamilpa Cuernavaca, Morelos, Mexico
| | - Andrés Fuentes Flores
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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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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