1
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Ghosh M, Raushel FM. Biosynthesis of UDP-α- N-Acetyl-d -mannosaminuronic Acid and CMP-β- N-Acetyl-d-neuraminic Acid for the Capsular Polysaccharides of Campylobacter jejuni. Biochemistry 2024; 63:688-698. [PMID: 38382015 PMCID: PMC10919079 DOI: 10.1021/acs.biochem.3c00664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/10/2024] [Accepted: 02/02/2024] [Indexed: 02/23/2024]
Abstract
Campylobacter jejuni is a human pathogen and a leading cause of food poisoning in North America and Europe. The exterior surface of the bacterial cell wall is attached to a polymeric coat of sugar molecules known as the capsular polysaccharide (CPS) that helps protect the organism from the host immune response. The CPS is composed of a repeating sequence of common and unusual sugar residues. In the HS:11 serotype of C. jejuni, we identified two enzymes in the gene cluster for CPS formation that are utilized for the biosynthesis of UDP-α-N-acetyl-d-mannosaminuronic acid (UDP-ManNAcA). In the first step, UDP-α-N-acetyl-d-glucosamine (UDP-GlcNAc) is epimerized at C2 to form UDP-α-N-acetyl-d-mannosamine (UDP-ManNAc). This product is then oxidized by a NAD+-dependent C6-dehydrogenase to form UDP-ManNAcA. In the HS:6 serotype (C. jejuni strain 81116), we identified three enzymes that are required for the biosynthesis of CMP-β-N-acetyl-d-neuraminic acid (CMP-Neu5Ac). In the first step, UDP-GlcNAc is epimerized at C2 and subsequently hydrolyzed to form N-acetyl-d-mannosamine (ManNAc) with the release of UDP. This product is then condensed with PEP by N-acetyl-d-neuraminate synthase to form N-acetyl-d-neuraminic acid (Neu5Ac). In the final step, CMP-N-acetyl-d-neuraminic acid synthase utilizes CTP to convert this product into CMP-Neu5Ac. A bioinformatic analysis of these five enzymes from C. jejuni serotypes HS:11 and HS:6 identified other bacterial species that can produce UDP-ManNAcA or CMP-Neu5Ac for CPS formation.
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Affiliation(s)
| | - Frank M. Raushel
- Department of Chemistry, Texas A&M University, College
Station, Texas 77845, United States
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2
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Woyda R, Oladeinde A, Endale D, Strickland T, Plumblee Lawrence J, Abdo Z. Virulence factors and antimicrobial resistance profiles of Campylobacter isolates recovered from consecutively reused broiler litter. Microbiol Spectr 2023; 11:e0323623. [PMID: 37882583 PMCID: PMC10871742 DOI: 10.1128/spectrum.03236-23] [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: 09/05/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Campylobacter is a leading cause of foodborne illness in the United States due to consumption of contaminated or mishandled food products, often associated with chicken meat. Campylobacter is common in the microbiota of avian and mammalian gut; however, acquisition of antimicrobial resistance genes (ARGs) and virulence factors (VFs) may result in strains that pose significant threat to public health. Although there are studies investigating the genetic diversity of Campylobacter strains isolated from post-harvest chicken samples, there are limited data on the genome characteristics of isolates recovered from preharvest broiler production. Here, we show that Campylobacter jejuni and Campylobacter coli differ in their carriage of antimicrobial resistance and virulence factors may also differ in their ability to persist in litter during consecutive grow-out of broiler flocks. We found that presence/absence of virulence factors needed for evasion of host defense mechanisms and gut colonization played an integral role in differentiating Campylobacter strains.
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Affiliation(s)
- Reed Woyda
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
- Program of Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | | | - Dinku Endale
- Southeast Watershed Research Laboratory, USDA, Tifton, Georgia, USA
| | | | | | - Zaid Abdo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
- Program of Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
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3
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Wohlgemuth R. Advances in the Synthesis and Analysis of Biologically Active Phosphometabolites. Int J Mol Sci 2023; 24:3150. [PMID: 36834560 PMCID: PMC9961378 DOI: 10.3390/ijms24043150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Phosphorus-containing metabolites cover a large molecular diversity and represent an important domain of small molecules which are highly relevant for life and represent essential interfaces between biology and chemistry, between the biological and abiotic world. The large but not unlimited amount of phosphate minerals on our planet is a key resource for living organisms on our planet, while the accumulation of phosphorus-containing waste is associated with negative effects on ecosystems. Therefore, resource-efficient and circular processes receive increasing attention from different perspectives, from local and regional levels to national and global levels. The molecular and sustainability aspects of a global phosphorus cycle have become of much interest for addressing the phosphorus biochemical flow as a high-risk planetary boundary. Knowledge of balancing the natural phosphorus cycle and the further elucidation of metabolic pathways involving phosphorus is crucial. This requires not only the development of effective new methods for practical discovery, identification, and high-information content analysis, but also for practical synthesis of phosphorus-containing metabolites, for example as standards, as substrates or products of enzymatic reactions, or for discovering novel biological functions. The purpose of this article is to review the advances which have been achieved in the synthesis and analysis of phosphorus-containing metabolites which are biologically active.
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Affiliation(s)
- Roland Wohlgemuth
- MITR, Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego Street 116, 90-924 Lodz, Poland; or
- Swiss Coordination Committee Biotechnology (SKB), 8021 Zurich, Switzerland
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4
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Woyda R, Oladeinde A, Endale D, Strickland T, Lawrence JP, Abdo Z. Broiler house environment and litter management practices impose selective pressures on antimicrobial resistance genes and virulence factors of Campylobacter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.526821. [PMID: 36778422 PMCID: PMC9915665 DOI: 10.1101/2023.02.02.526821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Campylobacter infections are a leading cause of bacterial diarrhea in humans globally. Infections are due to consumption of contaminated food products and are highly associated with chicken meat, with chickens being an important reservoir for Campylobacter. Here, we characterized the genetic diversity of Campylobacter species detected in broiler chicken litter over three consecutive flocks and determined their antimicrobial resistance and virulence factor profiles. Antimicrobial susceptibility testing and whole genome sequencing were performed on Campylobacter jejuni (n = 39) and Campylobacter coli (n = 5) isolates. All C. jejuni isolates were susceptible to all antibiotics tested while C. coli (n =4) were resistant to only tetracycline and harbored the tetracycline-resistant ribosomal protection protein (TetO). Virulence factors differed within and across grow houses but were explained by the isolates' flock cohort, species and multilocus sequence type. Virulence factors involved in the ability to invade and colonize host tissues and evade host defenses were absent from flock cohort 3 C. jejuni isolates as compared to flock 1 and 2 isolates. Our results show that virulence factors and antimicrobial resistance genes differed by the isolates' multilocus sequence type and by the flock cohort they were present in. These data suggest that the house environment and litter management practices performed imposed selective pressures on antimicrobial resistance genes and virulence factors. In particular, the absence of key virulence factors within the final flock cohort 3 isolates suggests litter reuse selected for Campylobacter strains that are less likely to colonize the chicken host.
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Affiliation(s)
- Reed Woyda
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
- Program of Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | | | - Dinku Endale
- Southeast Watershed Research Laboratory, USDA, Tifton, GA, 31793
| | | | | | - Zaid Abdo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
- Program of Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
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5
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Abstract
Enteric bacterial infections contribute substantially to global disease burden and mortality, particularly in the developing world. In vitro 2D monolayer cultures have provided critical insights into the fundamental virulence mechanisms of a multitude of pathogens, including Salmonella enterica serovars Typhimurium and Typhi, Vibrio cholerae, Shigella spp., Escherichia coli and Campylobacter jejuni, which have led to the identification of novel targets for antimicrobial therapy and vaccines. In recent years, the arsenal of experimental systems to study intestinal infections has been expanded by a multitude of more complex models, which have allowed to evaluate the effects of additional physiological and biological parameters on infectivity. Organoids recapitulate the cellular complexity of the human intestinal epithelium while 3D bioengineered scaffolds and microphysiological devices allow to emulate oxygen gradients, flow and peristalsis, as well as the formation and maintenance of stable and physiologically relevant microbial diversity. Additionally, advancements in ex vivo cultures and intravital imaging have opened new possibilities to study the effects of enteric pathogens on fluid secretion, barrier integrity and immune cell surveillance in the intact intestine. This review aims to present a balanced and updated overview of current intestinal in vitro and ex vivo methods for modeling of enteric bacterial infections. We conclude that the different paradigms are complements rather than replacements and their combined use promises to further our understanding of host-microbe interactions and their impacts on intestinal health.
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Affiliation(s)
- Nayere Taebnia
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- CONTACT Ute Römling Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Volker M. Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
- University of Tübingen, Tübingen, Germany
- Volker M. Lauschke Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
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6
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The Power of Biocatalysts for Highly Selective and Efficient Phosphorylation Reactions. Catalysts 2022. [DOI: 10.3390/catal12111436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Reactions involving the transfer of phosphorus-containing groups are of key importance for maintaining life, from biological cells, tissues and organs to plants, animals, humans, ecosystems and the whole planet earth. The sustainable utilization of the nonrenewable element phosphorus is of key importance for a balanced phosphorus cycle. Significant advances have been achieved in highly selective and efficient biocatalytic phosphorylation reactions, fundamental and applied aspects of phosphorylation biocatalysts, novel phosphorylation biocatalysts, discovery methodologies and tools, analytical and synthetic applications, useful phosphoryl donors and systems for their regeneration, reaction engineering, product recovery and purification. Biocatalytic phosphorylation reactions with complete conversion therefore provide an excellent reaction platform for valuable analytical and synthetic applications.
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7
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Riegert AS, Narindoshvili T, Coricello A, Richards NGJ, Raushel FM. Functional Characterization of Two PLP-Dependent Enzymes Involved in Capsular Polysaccharide Biosynthesis from Campylobacter jejuni. Biochemistry 2021; 60:2836-2843. [PMID: 34505775 DOI: 10.1021/acs.biochem.1c00439] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Campylobacter jejuni is a Gram-negative, pathogenic bacterium that causes campylobacteriosis, a form of gastroenteritis. C. jejuni is the most frequent cause of food-borne illness in the world, surpassing Salmonella and E. coli. Coating the surface of C. jejuni is a layer of sugar molecules known as the capsular polysaccharide that, in C. jejuni NCTC 11168, is composed of a repeating unit of d-glycero-l-gluco-heptose, d-glucuronic acid, d-N-acetyl-galactosamine, and d-ribose. The d-glucuronic acid moiety is further amidated with either serinol or ethanolamine. It is unknown how these modifications are synthesized and attached to the polysaccharide. Here, we report the catalytic activities of two previously uncharacterized, pyridoxal phosphate (PLP)-dependent enzymes, Cj1436 and Cj1437, from C. jejuni NCTC 11168. Using a combination of mass spectrometry and nuclear magnetic resonance, we determined that Cj1436 catalyzes the decarboxylation of l-serine phosphate to ethanolamine phosphate. Cj1437 was shown to catalyze the transamination of dihydroxyacetone phosphate to (S)-serinol phosphate in the presence of l-glutamate. The probable routes to the ultimate formation of the glucuronamide substructures in the capsular polysaccharides of C. jejuni are discussed.
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Affiliation(s)
- Alexander S Riegert
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Tamari Narindoshvili
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Adriana Coricello
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Nigel G J Richards
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Frank M Raushel
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States.,Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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8
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Riegert AS, Raushel FM. Functional and Structural Characterization of the UDP-Glucose Dehydrogenase Involved in Capsular Polysaccharide Biosynthesis from Campylobacter jejuni. Biochemistry 2021; 60:725-734. [PMID: 33621065 DOI: 10.1021/acs.biochem.0c00953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Campylobacter jejuni is a pathogenic organism that can cause campylobacteriosis in children and adults. Most commonly, campylobacter infection is brought on by consumption of raw or undercooked poultry, unsanitary drinking water, or pet feces. Surrounding the C. jejuni bacterium is a coat of sugar molecules known as the capsular polysaccharide (CPS). The capsular polysaccharide can be very diverse among the different strains of C. jejuni, and this diversity is considered important for evading the host immune system. Modifications to the CPS of C. jejuni NCTC 11168 include O-methylation, phosphoramidylation, and amidation of glucuronate with either serinol or ethanolamine. The enzymes responsible for amidation of glucuronate are currently unknown. In this study, Cj1441, an enzyme expressed from the CPS biosynthetic gene cluster in C. jejuni NCTC 11168, was shown to catalyze the oxidation of UDP-α-d-glucose into UDP-α-d-glucuronic acid with NAD+ as the cofactor. No amide products were found in an attempt to determine whether the putative thioester intermediate formed during the oxidation of UDP-glucose by Cj1441 could be captured in the presence of added amines. The three-dimensional crystal structure of Cj1441 was determined in the presence of NAD+ and UDP-glucose bound in the active site of the enzyme (Protein Data Bank entry 7KWS). A more thorough bioinformatic analysis of the CPS gene cluster suggests that the amidation activity is localized to the t-terminal half of Cj1438, a bifunctional enzyme that is currently annotated as a sugar transferase.
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Affiliation(s)
- Alexander S Riegert
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Frank M Raushel
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States.,Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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9
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Abstract
Natural nonproteinogenic amino acids vastly outnumber the well-known 22 proteinogenic amino acids. Such amino acids are generated in specialized metabolic pathways. In these pathways, diverse biosynthetic transformations, ranging from isomerizations to the stereospecific functionalization of C-H bonds, are employed to generate structural diversity. The resulting nonproteinogenic amino acids can be integrated into more complex natural products. Here we review recently discovered biosynthetic routes to freestanding nonproteinogenic α-amino acids, with an emphasis on work reported between 2013 and mid-2019.
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Affiliation(s)
- Jason B Hedges
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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10
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Taylor ZW, Raushel FM. Manganese-Induced Substrate Promiscuity in the Reaction Catalyzed by Phosphoglutamine Cytidylyltransferase from Campylobacter jejuni. Biochemistry 2019; 58:2144-2151. [PMID: 30929435 DOI: 10.1021/acs.biochem.9b00189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The leading cause of bacterial gastroenteritis, Campylobacter jejuni, is a Gram-negative pathogen that contains a unique O-methyl phosphoramidate (MeOPN) on its capsular polysaccharide. Previously, MeOPN has been linked to the evasion of host immune responses and serum resistance. Despite the involvement of MeOPN in pathogenicity, the complete biosynthesis of this modification is unknown; however, the first four enzymatic steps have been elucidated. The second enzyme in this pathway, Cj1416, is a CTP/phosphoglutamine cytididylyltransferase that catalyzes the displacement of pyrophosphate from MgCTP by l-glutamine phosphate to form CDP-l-glutamine. Initially, Cj1416 was predicted to use phosphoramidate to form cytidine diphosphoramidate, but no activity was detected with MgATP as a substrate. However, in the presence of MnCTP, Cj1416 can directly catalyze the formation of cytidine diphosphoramidate from phosphoramidate and MnCTP. Here we characterize the manganese-induced promiscuity of Cj1416. In the presence of Mn2+, Cj1416 catalyzes the formation of 12 different reaction products using l-glutamine phosphate, phosphoramidate, methyl phosphate, methyl phosphonate, phosphate, arsenate, ethanolamine phosphate, glycerol-1-phosphate, glycerol-2-phosphate, serinol phosphate, l-serine phosphate, or 3-phospho-d-glycerate as the nucleophile to displace pyrophosphate from CTP.
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Affiliation(s)
- Zane W Taylor
- Department of Biochemistry & Biophysics , Texas A&M University , College Station , Texas 77843 , United States
| | - Frank M Raushel
- Department of Biochemistry & Biophysics , Texas A&M University , College Station , Texas 77843 , United States.,Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States
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11
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12
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Petkowski JJ, Bains W, Seager S. Natural Products Containing 'Rare' Organophosphorus Functional Groups. Molecules 2019; 24:E866. [PMID: 30823503 PMCID: PMC6429109 DOI: 10.3390/molecules24050866] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/13/2019] [Accepted: 02/22/2019] [Indexed: 12/25/2022] Open
Abstract
Phosphorous-containing molecules are essential constituents of all living cells. While the phosphate functional group is very common in small molecule natural products, nucleic acids, and as chemical modification in protein and peptides, phosphorous can form P⁻N (phosphoramidate), P⁻S (phosphorothioate), and P⁻C (e.g., phosphonate and phosphinate) linkages. While rare, these moieties play critical roles in many processes and in all forms of life. In this review we thoroughly categorize P⁻N, P⁻S, and P⁻C natural organophosphorus compounds. Information on biological source, biological activity, and biosynthesis is included, if known. This review also summarizes the role of phosphorylation on unusual amino acids in proteins (N- and S-phosphorylation) and reviews the natural phosphorothioate (P⁻S) and phosphoramidate (P⁻N) modifications of DNA and nucleotides with an emphasis on their role in the metabolism of the cell. We challenge the commonly held notion that nonphosphate organophosphorus functional groups are an oddity of biochemistry, with no central role in the metabolism of the cell. We postulate that the extent of utilization of some phosphorus groups by life, especially those containing P⁻N bonds, is likely severely underestimated and has been largely overlooked, mainly due to the technological limitations in their detection and analysis.
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Affiliation(s)
- Janusz J Petkowski
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
| | - William Bains
- Rufus Scientific, 37 The Moor, Melbourn, Royston, Herts SG8 6ED, UK.
| | - Sara Seager
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
- Department of Physics, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
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13
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Thota VN, Ferguson MJ, Sweeney RP, Lowary TL. Synthesis of the
Campylobacter jejuni
81
‐
176 Strain Capsular Polysaccharide Repeating Unit Reveals the Absolute Configuration of its
O
‐Methyl Phosphoramidate Motif. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
| | - Michael J. Ferguson
- Department of ChemistryUniversity of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Ryan P. Sweeney
- Department of ChemistryUniversity of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Todd L. Lowary
- Department of ChemistryUniversity of Alberta Edmonton Alberta T6G 2G2 Canada
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14
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Thota VN, Ferguson MJ, Sweeney RP, Lowary TL. Synthesis of the Campylobacter jejuni 81-176 Strain Capsular Polysaccharide Repeating Unit Reveals the Absolute Configuration of its O-Methyl Phosphoramidate Motif. Angew Chem Int Ed Engl 2018; 57:15592-15596. [PMID: 30280458 DOI: 10.1002/anie.201810222] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 11/08/2022]
Abstract
The O-methyl phosphoramidate (MeOPN) motif is a non-stoichiometric modification of capsular polysaccharides (CPS) in ≈70 % of all Campylobacter jejuni strains. Infections by C. jejuni lead to food-borne illnesses and the CPS they produce are key virulence factors. The MeOPN phosphorus atom in these CPS is stereogenic and is found as a single stereoisomer. However, to date, the absolute stereochemistry at this atom has been undefined. We report the synthesis of the three repeating units found in C. jejuni 81-176 CPS; one of these possesses a MeOPN group. In the course of these studies we established that the stereochemistry of the phosphorus atom in this MeOPN group is R. These studies represent the first unequivocal proof of stereochemistry of this group in any C. jejuni CPS. The compounds produced are anticipated to be useful tools in investigations targeting the function and biosynthesis of this structurally-interesting modification, which so far has only been identified in campylobacter.
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Affiliation(s)
- V Narasimharao Thota
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Ryan P Sweeney
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
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15
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Zallot R, Oberg NO, Gerlt JA. 'Democratized' genomic enzymology web tools for functional assignment. Curr Opin Chem Biol 2018; 47:77-85. [PMID: 30268904 DOI: 10.1016/j.cbpa.2018.09.009] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 12/24/2022]
Abstract
The protein databases contain an exponentially growing number of sequences as a result of the recent increase in ease and decrease in cost of genome sequencing. The rate of data accumulation far exceeds the rate of functional studies, producing an increase in genomic 'dark matter', sequences for which no precise and validated function is defined. Publicly accessible, that is 'democratized,' genomic enzymology web tools are essential to leverage the protein and genome databases for discovery of the in vitro activities and in vivo functions of novel enzymes and proteins belonging to the dark matter. In this review, we discuss the use of web tools that have proven successful for functional assignment. We also describe a mechanism for ensuring the capture of published functional data so that the quality of both curated and automated annotations transfer can be improved.
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Affiliation(s)
- Rémi Zallot
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, United States
| | - Nils O Oberg
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, United States
| | - John A Gerlt
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, United States; Department of Chemistry, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, United States.
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16
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Taylor ZW, Chamberlain AR, Raushel FM. Substrate Specificity and Chemical Mechanism for the Reaction Catalyzed by Glutamine Kinase. Biochemistry 2018; 57:5447-5455. [PMID: 30142271 DOI: 10.1021/acs.biochem.8b00811] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Campylobacter jejuni, a leading cause of gastroenteritis worldwide, has a unique O-methyl phosphoramidate (MeOPN) moiety attached to its capsular polysaccharide. Investigations into the biological role of MeOPN have revealed that it contributes to the pathogenicity of C. jejuni, and this modification is important for the colonization of C. jejuni. Previously, the reactions catalyzed by four enzymes (Cj1418-Cj1415) from C. jejuni that are required for the biosynthesis of the phosphoramidate modification have been elucidated. Cj1418 (l-glutamine kinase) catalyzes the formation of the initial phosphoramidate bond with the ATP-dependent phosphorylation of the amide nitrogen of l-glutamine. Here we show that Cj1418 catalyzes the phosphorylation of l-glutamine through a three-step reaction mechanism via the formation of covalent pyrophosphorylated ( Enz-X-Pβ-Pγ) and phosphorylated ( Enz-X-Pβ) intermediates. In the absence of l-glutamine, the enzyme was shown to catalyze a positional isotope exchange (PIX) reaction within β-[18O4]-ATP in support of the formation of the Enz-X-Pβ-Pγintermediate. In the absence of ATP, the enzyme was shown to catalyze a molecular isotope exchange (MIX) reaction between l-glutamine phosphate and [15N-amide]-l-glutamine in direct support of the Enz-X-Pβintermediate. The active site nucleophile has been identified as His-737 based on the lack of activity of the H737N mutant and amino acid sequence comparisons. The enzyme was shown to also catalyze the phosphorylation of d-glutamine, γ-l-glutamyl hydroxamate, γ-l-glutamyl hydrazide, and β-l-aspartyl hydroxamate, in addition to l-glutamine.
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Affiliation(s)
- Zane W Taylor
- Department of Biochemistry and Biophysics , Texas A&M University , College Station , Texas 77843 , United States
| | - Alexandra R Chamberlain
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States
| | - Frank M Raushel
- Department of Biochemistry and Biophysics , Texas A&M University , College Station , Texas 77843 , United States.,Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States
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