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Sivaramakrishnan M, Veeraganti Naveen Prakash C, Chandrasekar B. Multifaceted roles of plant glycosyl hydrolases during pathogen infections: more to discover. PLANTA 2024; 259:113. [PMID: 38581452 DOI: 10.1007/s00425-024-04391-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 03/15/2024] [Indexed: 04/08/2024]
Abstract
MAIN CONCLUSION Carbohydrates are hydrolyzed by a family of carbohydrate-active enzymes (CAZymes) called glycosidases or glycosyl hydrolases. Here, we have summarized the roles of various plant defense glycosidases that possess different substrate specificities. We have also highlighted the open questions in this research field. Glycosidases or glycosyl hydrolases (GHs) are a family of carbohydrate-active enzymes (CAZymes) that hydrolyze glycosidic bonds in carbohydrates and glycoconjugates. Compared to those of all other sequenced organisms, plant genomes contain a remarkable diversity of glycosidases. Plant glycosidases exhibit activities on various substrates and have been shown to play important roles during pathogen infections. Plant glycosidases from different GH families have been shown to act upon pathogen components, host cell walls, host apoplastic sugars, host secondary metabolites, and host N-glycans to mediate immunity against invading pathogens. We could classify the activities of these plant defense GHs under eleven different mechanisms through which they operate during pathogen infections. Here, we have provided comprehensive information on the catalytic activities, GH family classification, subcellular localization, domain structure, functional roles, and microbial strategies to regulate the activities of defense-related plant GHs. We have also emphasized the research gaps and potential investigations needed to advance this topic of research.
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Affiliation(s)
| | | | - Balakumaran Chandrasekar
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS Pilani), Pilani, 333031, India.
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2
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Bitter J, Pfeiffer M, Borg AJE, Kuhlmann K, Pavkov-Keller T, Sánchez-Murcia PA, Nidetzky B. Enzymatic β-elimination in natural product O- and C-glycoside deglycosylation. Nat Commun 2023; 14:7123. [PMID: 37932298 PMCID: PMC10628242 DOI: 10.1038/s41467-023-42750-0] [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: 01/04/2023] [Accepted: 10/20/2023] [Indexed: 11/08/2023] Open
Abstract
Biological degradation of natural product glycosides involves, alongside hydrolysis, β-elimination for glycosidic bond cleavage. Here, we discover an O-glycoside β-eliminase (OGE) from Agrobacterium tumefaciens that converts the C3-oxidized O-β-D-glucoside of phloretin (a plant-derived flavonoid) into the aglycone and the 2-hydroxy-3-keto-glycal elimination product. While unrelated in sequence, OGE is structurally homologous to, and shows effectively the same Mn2+ active site as, the C-glycoside deglycosylating enzyme (CGE) from a human intestinal bacterium implicated in β-elimination of 3-keto C-β-D-glucosides. We show that CGE catalyzes β-elimination of 3-keto O- and C-β-D-glucosides while OGE is specific for the O-glycoside substrate. Substrate comparisons and mutagenesis for CGE uncover positioning of aglycone for protonic assistance by the enzyme as critically important for C-glycoside cleavage. Collectively, our study suggests convergent evolution of active site for β-elimination of 3-keto O-β-D-glucosides. C-Glycoside cleavage is a specialized feature of this active site which is elicited by substrate through finely tuned enzyme-aglycone interactions.
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Affiliation(s)
- Johannes Bitter
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010, Graz, Austria
| | - Martin Pfeiffer
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010, Graz, Austria
| | - Annika J E Borg
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010, Graz, Austria
- Austrian Centre of Industrial Biotechnology, Krenngasse 37, A-8010, Graz, Austria
| | - Kirill Kuhlmann
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, Humboldtstraße 50/III, A-8010, Graz, Austria
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, Humboldtstraße 50/III, A-8010, Graz, Austria
- BioTechMed-Graz, Mozartgasse 12/II, A-8010, Graz, Austria
- BioHealth Field of Excellence, University of Graz, Humboldtstraße 50, A-8010, Graz, Austria
| | - Pedro A Sánchez-Murcia
- Laboratory of Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto-Loewi Research Center, Medical University of Graz, Neue Stiftingstalstraße 6/III, A-8010, Graz, Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010, Graz, Austria.
- Austrian Centre of Industrial Biotechnology, Krenngasse 37, A-8010, Graz, Austria.
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3
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Quirke JCK, Crich D. GH47 and Other Glycoside Hydrolases Catalyze Glycosidic Bond Cleavage with the Assistance of Substrate Super-arming at the Transition State. ACS Catal 2021; 11:10308-10315. [PMID: 34777906 PMCID: PMC8579916 DOI: 10.1021/acscatal.1c02750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Super-armed glycosyl donors, whose substituents are predominantly held in pseudoaxial positions, exhibit strongly increased reactivity in glycosylation through significant stabilization of oxocarbenium-like transition states. Examination of X-ray crystal structures reveals that the GH47 family of glycoside hydrolases have evolved so as to distort their substrates away from the ground state conformation in such a manner as to present multiple C-O bonds in pseudoaxial positions and so benefit from conformational super-arming of their substrates, thereby enhancing catalysis. Through analysis of literature mutagenic studies, we show that a suitably placed aromatic residue in GHs 6 and 47 sterically enforces super-armed conformations on their substrates. GH families 45, 81, and 134 on the other hand impose conformational super-arming on their substrates, by maintaining the more active ring conformation through hydrogen bonding rather than steric interactions. The recognition of substrate super-arming by select GH families provides a further parallel with synthetic carbohydrate chemistry and nature and opens further avenues for the design of improved glycosidase inhibitors.
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Affiliation(s)
- Jonathan C K Quirke
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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4
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Structural basis of catalysis and substrate recognition by the NAD(H)-dependent α-d-glucuronidase from the glycoside hydrolase family 4. Biochem J 2021; 478:943-959. [PMID: 33565573 DOI: 10.1042/bcj20200824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/03/2021] [Accepted: 02/10/2021] [Indexed: 11/17/2022]
Abstract
Members of the glycoside hydrolase family 4 (GH4) employ an unusual glycosidic bond cleavage mechanism utilizing NAD(H) and a divalent metal ion, under reducing conditions. These enzymes act upon a diverse range of glycosides, and unlike most other GH families, homologs here are known to accommodate both α- and β-anomeric specificities within the same active site. Here, we report the catalytic properties and the crystal structures of TmAgu4B, an α-d-glucuronidase from the hyperthermophile Thermotoga maritima. The structures in three different states include the apo form, the NADH bound holo form, and the ternary complex with NADH and the reaction product d-glucuronic acid, at 2.15, 1.97 and 1.85 Å resolutions, respectively. These structures reveal the step-wise route of conformational changes required in the active site to achieve the catalytically competent state, and illustrate the direct role of residues that determine the reaction mechanism. Furthermore, a structural transition of a helical region in the active site to a turn geometry resulting in the rearrangement of a unique arginine residue governs the exclusive glucopyranosiduronic acid recognition in TmAgu4B. Mutational studies show that modifications of the glycone binding site geometry lead to catalytic failure and indicate overlapping roles of specific residues in catalysis and substrate recognition. The data highlight hitherto unreported molecular features and associated active site dynamics that determine the structure-function relationships within the unique GH4 family.
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5
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Müller M, Calvert M, Hottmann I, Kluj RM, Teufel T, Balbuchta K, Engelbrecht A, Selim KA, Xu Q, Borisova M, Titz A, Mayer C. The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases. J Biol Chem 2021; 296:100519. [PMID: 33684445 PMCID: PMC8054146 DOI: 10.1016/j.jbc.2021.100519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 11/11/2022] Open
Abstract
Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze the β-1,4-glycosidic bonds connecting N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little is known about exo-β-N-acetylmuramidases, which catalyze an exo-lytic cleavage of β-1,4-MurNAc entities from the non-reducing ends of peptidoglycan chains. Such an enzyme was identified earlier in the bacterium Bacillus subtilis, but the corresponding gene has remained unknown so far. We now report that ybbC of B. subtilis, renamed namZ, encodes the reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects under starvation conditions, indicating a role of NamZ in cell wall turnover and recycling. Recombinant NamZ protein specifically hydrolyzed the artificial substrate para-nitrophenyl β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-l-alanine amidase AmiE, NamZ degraded intact peptidoglycan by sequential hydrolysis from the non-reducing ends. A structure model of NamZ, built on the basis of two crystal structures of putative orthologs from Bacteroides fragilis, revealed a two-domain structure including a Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein family of unknown function, is now classified as the founding member of a new family of glycosidases (CAZy GH171; www.cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less frequently found in individual genomes within Firmicutes (Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria.
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Affiliation(s)
- Maraike Müller
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Matthew Calvert
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Isabel Hottmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Robert Maria Kluj
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Tim Teufel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Katja Balbuchta
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alicia Engelbrecht
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany; Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Giza, Egypt
| | - Qingping Xu
- GM/CA @ APS, Argonne National Laboratory, Lemont, Illinois, USA
| | - Marina Borisova
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.
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Quirke JCK, Crich D. Glycoside Hydrolases Restrict the Side Chain Conformation of Their Substrates To Gain Additional Transition State Stabilization. J Am Chem Soc 2020; 142:16965-16973. [PMID: 32877175 PMCID: PMC7544649 DOI: 10.1021/jacs.0c05592] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Carbohydrate side chain conformation confers a significant influence on reactivity during glycosylation and anomeric bond hydrolysis due to stabilization of the oxocarbenium-like transition state. By analysis of 513 pyranoside-bound glycoside hydrolase (GH) crystal structures, we determine that most glucosidases and β-mannosidases preferentially bind their substrates in the most reactive gauche,gauche (gg) conformation, thereby maximizing stabilization of the corresponding oxocarbenium ion-like transition state during hydrolysis. α-Galactoside hydrolases mostly show a preference for the second most activating gauche,trans (gt) conformation to avoid the energy penalty that would arise from imposing the gg conformation on galacto-configured ligands. These preferences stand in stark contrast to the side chain populations observed for these sugars both in free solution and bound to nonhydrolytic proteins, where for the most part a much greater diversity of side chain conformations is observed. Analysis of sequences of GH-ligand complexes reveals that side chain restriction begins with the enzyme-substrate complex and persists through the transition state until release of the hydrolysis product, despite changes in ring conformation along the reaction coordinate. This work will inform the design of new generations of glycosidase inhibitors with restricted side chains that confer higher selectivity and/or affinity.
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Affiliation(s)
- Jonathan C K Quirke
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
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7
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Mohapatra SB, Manoj N. A conserved π-helix plays a key role in thermoadaptation of catalysis in the glycoside hydrolase family 4. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140523. [PMID: 32853774 DOI: 10.1016/j.bbapap.2020.140523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/22/2020] [Accepted: 07/29/2020] [Indexed: 01/21/2023]
Abstract
Here, we characterize the role of a π-helix in the molecular mechanisms underlying thermoadaptation in the glycoside hydrolase family 4 (GH4). The interspersed π-helix present in a subgroup is evolutionarily related to a conserved α-helix in other orthologs by a single residue insertion/deletion event. The insertional residue, Phe407, in a hyperthermophilic α-glucuronidase, makes specific interactions across the inter-subunit interface. In order to establish the sequence-structure-stability implications of the π-helix, the wild-type and the deletion variant (Δ407) were characterized. The variant showed a significant lowering of melting temperature and optimum temperature for the highest activity. Crystal structures of the proteins show a transformation of the π-helix to a continuous α-helix in the variant, identical to that in orthologs lacking this insertion. Thermodynamic parameters were determined from stability curves representing the temperature dependence of unfolding free energy. Though the proteins display maximum stabilities at similar temperatures, a higher melting temperature in the wild-type is achieved by a combination of higher enthalpy and lower heat capacity of unfolding. Comparisons of the structural changes, and the activity and thermodynamic profiles allow us to infer that specific non-covalent interactions, and the existence of residual structure in the unfolded state, are crucial determinants of its thermostability. These features permit the enzyme to balance the preservation of structure at a higher temperature with the thermodynamic stability required for optimum catalysis.
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Affiliation(s)
- Samar Bhallabha Mohapatra
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Narayanan Manoj
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India.
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8
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Vetter ND, Jagdhane RC, Richter BJ, Palmer DRJ. Carbocyclic Substrate Analogues Reveal Kanosamine Biosynthesis Begins with the α-Anomer of Glucose 6-Phosphate. ACS Chem Biol 2020; 15:2205-2211. [PMID: 32786294 DOI: 10.1021/acschembio.0c00409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
NtdC is an NAD-dependent dehydrogenase that catalyzes the conversion of glucose 6-phosphate (G6P) to 3-oxo-glucose 6-phosphate (3oG6P), the first step in kanosamine biosynthesis in Bacillus subtilis and other closely-related bacteria. The NtdC-catalyzed reaction is unusual because 3oG6P undergoes rapid ring opening, resulting in a 1,3-dicarbonyl compound that is inherently unstable due to enolate formation. We have reported the steady-state kinetic behavior of NtdC, but many questions remain about the nature of this reaction, including whether it is the α-anomer, β-anomer, or open-chain form that is the substrate for the enzyme. Here, we report the synthesis of carbocyclic G6P analogues by two routes, one based upon the Ferrier II rearrangement to generate the carbocycle and one based upon a Claisen rearrangement. We were able to synthesize both pseudo-anomers of carbaglucose 6-phosphate (C6P) using the Ferrier approach, and activity assays revealed that the pseudo-α-anomer is a good substrate for NtdC, while the pseudo-β-anomer and the open-chain analogue, sorbitol 6-phosphate (S6P), are not substrates. A more efficient synthesis of α-C6P was achieved using the Claisen rearrangement approach, which allowed for a thorough evaluation of the NtdC-catalyzed oxidation of α-C6P. The requirement for the α-anomer indicates that NtdC and NtdA, the subsequent enzyme in the pathway, have co-evolved to recognize the α-anomer in order to avoid mutarotation between enzymatic steps.
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Affiliation(s)
- Natasha D. Vetter
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Rajendra C. Jagdhane
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Brett J. Richter
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - David R. J. Palmer
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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9
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Teze D, Shuoker B, Chaberski EK, Kunstmann S, Fredslund F, Nielsen TS, Stender EGP, Peters GHJ, Karlsson EN, Welner DH, Hachem MA. The Catalytic Acid–Base in GH109 Resides in a Conserved GGHGG Loop and Allows for Comparable α-Retaining and β-Inverting Activity in an N-Acetylgalactosaminidase from Akkermansia muciniphila. ACS Catal 2020. [DOI: 10.1021/acscatal.9b04474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- David Teze
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Lyngby, Denmark
- Enzyme Engineering and Structural Biology, The Novo Nordisk Center for Biosustainability, Kemitorvet, Building 220, DK-2800 Lyngby, Denmark
| | - Bashar Shuoker
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Lyngby, Denmark
- Biotechnology, Department of Chemistry (KILU), Lund University, Post Office Box 124, 221 00 Lund, Sweden
| | - Evan Kirk Chaberski
- Enzyme Engineering and Structural Biology, The Novo Nordisk Center for Biosustainability, Kemitorvet, Building 220, DK-2800 Lyngby, Denmark
| | - Sonja Kunstmann
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Folmer Fredslund
- Enzyme Engineering and Structural Biology, The Novo Nordisk Center for Biosustainability, Kemitorvet, Building 220, DK-2800 Lyngby, Denmark
| | - Tine Sofie Nielsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Emil G. P. Stender
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Günther H. J. Peters
- Department of Chemistry, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Eva Nordberg Karlsson
- Biotechnology, Department of Chemistry (KILU), Lund University, Post Office Box 124, 221 00 Lund, Sweden
| | - Ditte Hededam Welner
- Enzyme Engineering and Structural Biology, The Novo Nordisk Center for Biosustainability, Kemitorvet, Building 220, DK-2800 Lyngby, Denmark
| | - Maher Abou Hachem
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Lyngby, Denmark
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10
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Grand M, Blancato VS, Espariz M, Deutscher J, Pikis A, Hartke A, Magni C, Sauvageot N. Enterococcus faecalisMalR acts as a repressor of the maltose operons and additionally mediates their catabolite repression via direct interaction with seryl‐phosphorylated‐HPr. Mol Microbiol 2019; 113:464-477. [DOI: 10.1111/mmi.14431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/13/2019] [Accepted: 11/19/2019] [Indexed: 12/26/2022]
Affiliation(s)
| | - Victor Sebastián Blancato
- Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Rosario Argentina
| | - Martín Espariz
- Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Rosario Argentina
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris‐Saclay Jouy‐en‐Josas France
- UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico‐Chimique Paris France
| | - Andreas Pikis
- Center for Drug Evaluation and Research, Food and Drug Administration Silver Spring Maryland
- Microbial Biochemistry and Genetics Unit, Laboratory of Cell and Developmental Biology NIDCR, National Institutes of Health Bethesda Maryland
| | | | - Christian Magni
- Instituto de Biología Molecular y Celular de Rosario (IBR‐CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas Universidad Nacional de Rosario Rosario Argentina
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11
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Bhatia S, Singh A, Batra N, Singh J. Microbial production and biotechnological applications of α-galactosidase. Int J Biol Macromol 2019; 150:1294-1313. [PMID: 31747573 DOI: 10.1016/j.ijbiomac.2019.10.140] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/12/2019] [Accepted: 10/15/2019] [Indexed: 12/13/2022]
Abstract
α-Galactosidase, (E.C. 3.2.1.22) is an exoglycosidase that target galactooligosaccharides such as raffinose, melibiose, stachyose and branched polysaccharides like galactomannans and galacto-glucomannans by catalysing the hydrolysis of α-1,6 linked terminal galactose residues. The enzyme has been isolated and characterized from microbial, plant and animal sources. This ubiquitous enzyme possesses physiological significance and immense industrial potential. Optimization of the growth conditions and efficient purification strategies can lead to a significant increase in the enzyme production. To boost commercial productivity, cloning of novel α-galactosidase genes and their heterologous expression in suitable host has gained popularity. Enzyme immobilization leads to its greater reutilization, superior thermostability, pH tolerance and increased activity. The enzyme is well explored in food industry in the removal of raffinose family oligosaccharides (RFOs) in soymilk and sugar crystallization process. It also improves animal feed quality and biomass processing. Applications of the enzyme is in the area of biomedicine includes therapeutic advances in treatment of Fabry disease, blood group conversion and removal of α-gal type immunogenic epitopes in xenotransplantation. With considerable biotechnological applications, this enzyme has been vastly commercialized and holds greater future prospects.
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Affiliation(s)
- Sonu Bhatia
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Abhinashi Singh
- Department of Biotechnology, G.G.D.S.D. College, Sector-32-C, Chandigarh, India
| | - Navneet Batra
- Department of Biotechnology, G.G.D.S.D. College, Sector-32-C, Chandigarh, India
| | - Jagtar Singh
- Department of Biotechnology, Panjab University, Chandigarh, India.
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12
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Wallace MD, Stubbs KA. General Synthesis of 3,4‐Dinitrophenyl α‐Glycopyranosides. ChemistrySelect 2019. [DOI: 10.1002/slct.201903489] [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]
Affiliation(s)
- Michael D. Wallace
- School of Molecular SciencesUniversity of Western Australia 35 Stirling Highway Crawley WA 6009 Australia
| | - Keith A. Stubbs
- School of Molecular SciencesUniversity of Western Australia 35 Stirling Highway Crawley WA 6009 Australia
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13
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Strazzulli A, Cobucci-Ponzano B, Iacono R, Giglio R, Maurelli L, Curci N, Schiano-di-Cola C, Santangelo A, Contursi P, Lombard V, Henrissat B, Lauro FM, Fontes CMGA, Moracci M. Discovery of hyperstable carbohydrate-active enzymes through metagenomics of extreme environments. FEBS J 2019; 287:1116-1137. [PMID: 31595646 DOI: 10.1111/febs.15080] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/23/2019] [Accepted: 10/01/2019] [Indexed: 12/11/2022]
Abstract
The enzymes from hyperthermophilic microorganisms populating volcanic sites represent interesting cases of protein adaptation and biotransformations under conditions where conventional enzymes quickly denature. The difficulties in cultivating extremophiles severely limit access to this class of biocatalysts. To circumvent this problem, we embarked on the exploration of the biodiversity of the solfatara Pisciarelli, Agnano (Naples, Italy), to discover hyperthermophilic carbohydrate-active enzymes (CAZymes) and to characterize the entire set of such enzymes in this environment (CAZome). Here, we report the results of the metagenomic analysis of two mud/water pools that greatly differ in both temperature and pH (T = 85 °C and pH 5.5; T = 92 °C and pH 1.5, for Pool1 and Pool2, respectively). DNA deep sequencing and following in silico analysis led to 14 934 and 17 652 complete ORFs in Pool1 and Pool2, respectively. They exclusively belonged to archaeal cells and viruses with great genera variance within the phylum Crenarchaeota, which reflected the difference in temperature and pH of the two Pools. Surprisingly, 30% and 62% of all of the reads obtained from Pool1 and 2, respectively, had no match in nucleotide databanks. Genes associated with carbohydrate metabolism were 15% and 16% of the total in the two Pools, with 278 and 308 putative CAZymes in Pool1 and 2, corresponding to ~ 2.0% of all ORFs. Biochemical characterization of two CAZymes of a previously unknown archaeon revealed a novel subfamily GH5_19 β-mannanase/β-1,3-glucanase whose hemicellulose specificity correlates with the vegetation surrounding the sampling site, and a novel NAD+ -dependent GH109 with a previously unreported β-N-acetylglucosaminide/β-glucoside specificity. DATABASES: The sequencing reads are available in the NCBI Sequence Read Archive (SRA) database under the accession numbers SRR7545549 (Pool1) and SRR7545550 (Pool2). The sequences of GH5_Pool2 and GH109_Pool2 are available in GenBank database under the accession numbers MK869723 and MK86972, respectively. The environmental data relative to Pool1 and Pool2 (NCBI BioProject PRJNA481947) are available in the Biosamples database under the accession numbers SAMN09692669 (Pool1) and SAMN09692670 (Pool2).
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Affiliation(s)
- Andrea Strazzulli
- Department of Biology, University of Naples "Federico II", Complesso Universitario di Monte S. Angelo, Naples, Italy.,Task Force on Microbiome Studies, University of Naples Federico II, Italy
| | | | - Roberta Iacono
- Department of Biology, University of Naples "Federico II", Complesso Universitario di Monte S. Angelo, Naples, Italy.,Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Rosa Giglio
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Luisa Maurelli
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Nicola Curci
- Department of Biology, University of Naples "Federico II", Complesso Universitario di Monte S. Angelo, Naples, Italy.,Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Corinna Schiano-di-Cola
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Annalisa Santangelo
- Department of Biology, University of Naples "Federico II", Complesso Universitario di Monte S. Angelo, Naples, Italy
| | - Patrizia Contursi
- Department of Biology, University of Naples "Federico II", Complesso Universitario di Monte S. Angelo, Naples, Italy.,Task Force on Microbiome Studies, University of Naples Federico II, Italy
| | - Vincent Lombard
- Centre National de la Recherche Scientifique, INRA, AFMB, USC 1408, Aix Marseille Univ, France
| | - Bernard Henrissat
- Centre National de la Recherche Scientifique, INRA, AFMB, USC 1408, Aix Marseille Univ, France.,Department Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Federico M Lauro
- Asian School of the Environment, Nanyang Technological University, Singapore City, Singapore.,Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore City, Singapore
| | - Carlos M G A Fontes
- NZYTech LDA, Estrada Do Paco Do Lumiar, Lisbon, Portugal.,CIISA - Faculdade de Medicina Veterinária, Universidade de Lisboa, Portugal
| | - Marco Moracci
- Department of Biology, University of Naples "Federico II", Complesso Universitario di Monte S. Angelo, Naples, Italy.,Task Force on Microbiome Studies, University of Naples Federico II, Italy.,Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
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14
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Structure of an α-glucuronidase in complex with Co2+ and citrate provides insights into the mechanism and substrate recognition in the family 4 glycosyl hydrolases. Biochem Biophys Res Commun 2019; 518:197-203. [DOI: 10.1016/j.bbrc.2019.08.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 08/06/2019] [Indexed: 11/23/2022]
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15
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Mahanta N, Hicks KA, Naseem S, Zhang Y, Fedoseyenko D, Ealick SE, Begley TP. Menaquinone Biosynthesis: Biochemical and Structural Studies of Chorismate Dehydratase. Biochemistry 2019; 58:1837-1840. [DOI: 10.1021/acs.biochem.9b00105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Nilkamal Mahanta
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Katherine A. Hicks
- Department of Chemistry, The State University of New York Cortland, Cortland, New York 13045, United States
| | - Saad Naseem
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yang Zhang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Dmytro Fedoseyenko
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Steven E. Ealick
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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16
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Kluj RM, Ebner P, Adamek M, Ziemert N, Mayer C, Borisova M. Recovery of the Peptidoglycan Turnover Product Released by the Autolysin Atl in Staphylococcus aureus Involves the Phosphotransferase System Transporter MurP and the Novel 6-phospho- N-acetylmuramidase MupG. Front Microbiol 2018; 9:2725. [PMID: 30524387 PMCID: PMC6262408 DOI: 10.3389/fmicb.2018.02725] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 10/24/2018] [Indexed: 11/29/2022] Open
Abstract
The peptidoglycan of the bacterial cell wall undergoes a permanent turnover during cell growth and differentiation. In the Gram-positive pathogen Staphylococcus aureus, the major peptidoglycan hydrolase Atl is required for accurate cell division, daughter cell separation and autolysis. Atl is a bifunctional N-acetylmuramoyl-L-alanine amidase/endo-β-N-acetylglucosaminidase that releases peptides and the disaccharide N-acetylmuramic acid-β-1,4-N-acetylglucosamine (MurNAc-GlcNAc) from the peptido-glycan. Here we revealed the recycling pathway of the cell wall turnover product MurNAc-GlcNAc in S. aureus. The latter disaccharide is internalized and concomitantly phosphorylated by the phosphotransferase system (PTS) transporter MurP, which had been implicated previously in the uptake and phosphorylation of MurNAc. Since MurP mutant cells accumulate MurNAc-GlcNAc and not MurNAc in the culture medium during growth, the disaccharide represents the physiological substrate of the PTS transporter. We further identified and characterized a novel 6-phospho-N-acetylmuramidase, named MupG, which intracellularly hydrolyses MurNAc 6-phosphate-GlcNAc, the product of MurP-uptake and phosphorylation, yielding MurNAc 6-phosphate and GlcNAc. MupG is the first characterized representative of a novel family of glycosidases containing domain of unknown function 871 (DUF871). The corresponding gene mupG (SAUSA300_0192) of S. aureus strain USA300 is the first gene within a putative operon that also includes genes encoding the MurNAc 6-phosphate etherase MurQ, MurP, and the putative transcriptional regulator MurR. Using mass spectrometry, we observed cytoplasmic accumulation of MurNAc 6-phosphate-GlcNAc in ΔmupG and ΔmupGmurQ markerless non-polar deletion mutants, but not in the wild type or in the complemented ΔmupG strain. MurNAc 6-phosphate-GlcNAc levels in the mutants increased during stationary phase, in accordance with previous observations regarding peptidoglycan recycling in S. aureus.
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Affiliation(s)
- Robert Maria Kluj
- Microbiology/Biotechnology, Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Patrick Ebner
- Microbial Genetics, Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Martina Adamek
- Microbiology/Biotechnology, Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Nadine Ziemert
- Microbiology/Biotechnology, Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Christoph Mayer
- Microbiology/Biotechnology, Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Marina Borisova
- Microbiology/Biotechnology, Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
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17
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Sannikova N, Gerak CAN, Shidmoossavee FS, King DT, Shamsi Kazem Abadi S, Lewis AR, Bennet AJ. Both Chemical and Non-Chemical Steps Limit the Catalytic Efficiency of Family 4 Glycoside Hydrolases. Biochemistry 2018; 57:3378-3386. [PMID: 29630821 DOI: 10.1021/acs.biochem.8b00117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The glycoside hydrolase family 4 (GH4) α-galactosidase from Citrobacter freundii (MelA) catalyzes the hydrolysis of fluoro-substituted phenyl α-d-galactopyranosides by utilizing two cofactors, NAD+ and a metal cation, under reducing conditions. In order to refine the mechanistic understanding of this GH4 enzyme, leaving group effects were measured with various metal cations. The derived βlg value on V/ K for strontium activation is indistinguishable from zero (0.05 ± 0.12). Deuterium kinetic isotope effects (KIEs) were measured for the activated substrates 2-fluorophenyl and 4-fluorophenyl α-d-galactopyranosides in the presence of Sr2+, Y3+, and Mn2+, where the isotopic substitution was on the carbohydrate at C-2 and/or C-3. To determine the contributing factors to the virtual transition state (TS) on which the KIEs report, kinetic isotope effects on isotope effects were measured on these KIEs using doubly deuterated substrates. The measured D V/ K KIEs for MelA-catalyzed hydrolysis of 2-fluorophenyl α-d-galactopyranoside are closer to unity than the measured effects on 4-fluorophenyl α-d-galactopyranoside, irrespective of the site of isotopic substitution and of the metal cation activator. These observations are consistent with hydride transfer at C-3 to the on-board NAD+, deprotonation at C-2, and a non-chemical step contributing to the virtual TS for V/ K.
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18
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Engineering of Escherichia coli to facilitate efficient utilization of isomaltose and panose in industrial glucose feedstock. Appl Microbiol Biotechnol 2016; 101:2057-2066. [PMID: 27933453 PMCID: PMC5309279 DOI: 10.1007/s00253-016-8037-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/27/2016] [Accepted: 11/26/2016] [Indexed: 10/25/2022]
Abstract
Industrial glucose feedstock prepared by enzymatic digestion of starch typically contains significant amounts of disaccharides such as maltose and isomaltose and trisaccharides such as maltotriose and panose. Maltose and maltosaccharides can be utilized in Escherichia coli fermentation using industrial glucose feedstock because there is an intrinsic assimilation pathway for these sugars. However, saccharides that contain α-1,6 bonds, such as isomaltose and panose, are still present after fermentation because there is no metabolic pathway for these sugars. To facilitate more efficient utilization of glucose feedstock, we introduced glvA, which encodes phospho-α-glucosidase, and glvC, which encodes a subunit of the phosphoenolpyruvate-dependent maltose phosphotransferase system (PTS) of Bacillus subtilis, into E. coli. The heterologous expression of glvA and glvC conferred upon the recombinant the ability to assimilate isomaltose and panose. The recombinant E. coli assimilated not only other disaccharides but also trisaccharides, including alcohol forms of these saccharides, such as isomaltitol. To the best of our knowledge, this is the first report to show the involvement of the microbial PTS in the assimilation of trisaccharides. Furthermore, we demonstrated that an L-lysine-producing E. coli harboring glvA and glvC converted isomaltose and panose to L-lysine efficiently. These findings are expected to be beneficial for industrial fermentation.
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19
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Structural Insight of a Trimodular Halophilic Cellulase with a Family 46 Carbohydrate-Binding Module. PLoS One 2015; 10:e0142107. [PMID: 26562160 PMCID: PMC4643050 DOI: 10.1371/journal.pone.0142107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 10/16/2015] [Indexed: 01/08/2023] Open
Abstract
Cellulases are the key enzymes used in the biofuel industry. A typical cellulase contains a catalytic domain connected to a carbohydrate-binding module (CBM) through a flexible linker. Here we report the structure of an atypical trimodular cellulase which harbors a catalytic domain, a CBM46 domain and a rigid CBM_X domain between them. The catalytic domain shows the features of GH5 family, while the CBM46 domain has a sandwich-like structure. The catalytic domain and the CBM46 domain form an extended substrate binding cleft, within which several tryptophan residues are well exposed. Mutagenesis assays indicate that these residues are essential for the enzymatic activities. Gel affinity electrophoresis shows that these tryptophan residues are involved in the polysaccharide substrate binding. Also, electrostatic potential analysis indicates that almost the entire solvent accessible surface of CelB is negatively charged, which is consistent with the halophilic nature of this enzyme.
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20
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Function and Structure Studies of GH Family 31 and 97 α-Glycosidases. Biosci Biotechnol Biochem 2014; 75:2269-77. [DOI: 10.1271/bbb.110610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Abstract
Over the sixty years since Koshland initially formulated the classical mechanisms for retaining and inverting glycosidases, researchers have assembled a large body of supporting evidence and have documented variations of these mechanisms. Recently, however, researchers have uncovered a number of completely distinct mechanisms for enzymatic cleavage of glycosides involving elimination and/or hydration steps. In family GH4 and GH109 glycosidases, the reaction proceeds via transient NAD(+)-mediated oxidation at C3, thereby acidifying the proton at C2 and allowing for elimination across the C1-C2 bond. Subsequent Michael-type addition of water followed by reduction at C3 generates the hydrolyzed product. Enzymes employing this mechanism can hydrolyze thioglycosides as well as both anomers of activated substrates. Sialidases employ a conventional retaining mechanism in which a tyrosine functions as the nucleophile, but in some cases researchers have observed off-path elimination end products. These reactions occur via the normal covalent intermediate, but instead of an attack by water on the anomeric center, the catalytic acid/base residue abstracts an adjacent proton. These enzymes can also catalyze hydration of the enol ether via the reverse pathway. Reactions of α-(1,4)-glucan lyases also proceed through a covalent intermediate with subsequent abstraction of an adjacent proton to give elimination. However, in this case, the departing carboxylate "nucleophile" serves as the base in a concerted but asynchronous syn-elimination process. These enzymes perform only elimination reactions. Polysaccharide lyases, which act on uronic acid-containing substrates, also catalyze only elimination reactions. Substrate binding neutralizes the charge on the carboxylate, which allows for abstraction of the proton on C5 and leads to an elimination reaction via an E1cb mechanism. These enzymes can also cleave thioglycosides, albeit slowly. The unsaturated product of polysaccharide lyases can then serve as a substrate for a hydration reaction carried out by unsaturated glucuronyl hydrolases. This hydration is initiated by protonation at C4 and proceeds in a Markovnikov fashion rather than undergoing a Michael-type addition, giving a hemiketal at C5. This hemiketal then undergoes a rearrangement that results in cleavage of the anomeric bond. These enzymes can also hydrolyze thioglycosides efficiently and slowly turn over substrates with inverted anomeric configuration. The mechanisms discussed in this Account proceed through transition states that involve either positive or negative charges, unlike the exclusively cationic transition states of the classical Koshland retaining and inverting glycosidases. In addition, the distribution of this charge throughout the substrate can vary substantially. The nature of these mechanisms and their transition states means that any inhibitors or inactivators of these unusual enzymes probably differ from those presently used for Koshland retaining or inverting glycosidases.
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Affiliation(s)
- Seino A. K. Jongkees
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Stephen G. Withers
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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22
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Haldar S, Patra A, Bera M. Exploring the catalytic activity of new water soluble dinuclear copper(ii) complexes towards the glycoside hydrolysis. RSC Adv 2014. [DOI: 10.1039/c4ra09800e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Water soluble dicopper(ii/ii) complexes of a new dinucleating ligand, H3phpda were synthesized and characterized for the investigation of glycoside hydrolysis.
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Affiliation(s)
| | - Ayan Patra
- Department of Chemistry
- University of Kalyani
- Kalyani, India
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23
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Chakladar S, Shamsi Kazem Abadi S, Bennet AJ. A mechanistic study on the α-N-acetylgalactosaminidase from E. meningosepticum: a family 109 glycoside hydrolase. MEDCHEMCOMM 2014. [DOI: 10.1039/c4md00104d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studies on the mechanism of action used by a GH109 enzyme.
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24
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Hemamalini A, Das TM. Studies on the synthesis of a sugar triazole based ligand for protein and DNA binding. RSC Adv 2014. [DOI: 10.1039/c4ra04084h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Bis-triazole derivatives accomplished by [3 + 2] cycloaddition methodology were well characterized. Interaction of bis-triazoles with BSA and CT-DNA had good correlation with experimental and docking studies. Compounds showed moderate to excellent antibacterial activity.
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Affiliation(s)
| | - Thangamuthu Mohan Das
- Department of Organic Chemistry
- University of Madras
- Chennai-600 025, India
- Department of Chemistry
- School of Basic and Applied Sciences
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25
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Jordan DB, Lee CC, Wagschal K, Braker JD. Activation of a GH43 β-xylosidase by divalent metal cations: slow binding of divalent metal and high substrate specificity. Arch Biochem Biophys 2013; 533:79-87. [PMID: 23500142 DOI: 10.1016/j.abb.2013.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 11/19/2022]
Abstract
RS223-BX of glycoside hydrolase family 43 is a β-d-xylosidase that is strongly activated (k(cat)/K(m) as much as 116-fold) by the addition of divalent metal cations, Ca(2+), Co(2+), Fe(2+), Mg(2+), Mn(2+) and Ni(2+). Slow activation by Mg(2+) was demonstrated (k(on) 0.013 s(-1) mM(-1), k(off) 0.008 s(-1)) at pH 7.0 and 25 °C. k(off) and k(on) values are independent of Mg(2+) concentration, but k(off) and k(on) are slower in the presence of increasing levels of substrate 4-nitrophenyl-β-D-xylopyranoside. The kinetics strongly suggest that M(2+) binds to the enzyme rapidly, forming E M(2+), followed by slow isomerization to the activated enzyme, E* M(2+). Moderately high values of kcat (7-30 s(-1)) were found for M(2+)-activated RS223-BX acting on xylobiose (natural substrate) at pH 7.0 and 25 °C. Certain M(2+)-activated RS223-BX exhibit the highest reported values of k(cat)/K(m) of any β-xylosidase acting on natural substrates: for example, at pH 7.0 and 25°C, xylobiose (Mn(2+), 190 s(-1) mM(-1)), xylotriose (Ca(2+), 150 s(-1) mM(-1)) and xylotetraose (Ca(2+), 260 s(-1) mM(-1)). There is potential for the enzyme to add value to industrial saccharification operations at low substrate and high d-glucose and high d-xylose concentrations.
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Affiliation(s)
- Douglas B Jordan
- USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604, USA.
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26
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Mokhtari A, Blancato VS, Repizo GD, Henry C, Pikis A, Bourand A, de Fátima Álvarez M, Immel S, Mechakra-Maza A, Hartke A, Thompson J, Magni C, Deutscher J. Enterococcus faecalis utilizes maltose by connecting two incompatible metabolic routes via a novel maltose 6'-phosphate phosphatase (MapP). Mol Microbiol 2013; 88:234-53. [PMID: 23490043 DOI: 10.1111/mmi.12183] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 11/30/2022]
Abstract
Similar to Bacillus subtilis, Enterococcus faecalis transports and phosphorylates maltose via a phosphoenolpyruvate (PEP):maltose phosphotransferase system (PTS). The maltose-specific PTS permease is encoded by the malT gene. However, E. faecalis lacks a malA gene encoding a 6-phospho-α-glucosidase, which in B. subtilis hydrolyses maltose 6'-P into glucose and glucose 6-P. Instead, an operon encoding a maltose phosphorylase (MalP), a phosphoglucomutase and a mutarotase starts upstream from malT. MalP was suggested to split maltose 6-P into glucose 1-P and glucose 6-P. However, purified MalP phosphorolyses maltose but not maltose 6'-P. We discovered that the gene downstream from malT encodes a novel enzyme (MapP) that dephosphorylates maltose 6'-P formed by the PTS. The resulting intracellular maltose is cleaved by MalP into glucose and glucose 1-P. Slow uptake of maltose probably via a maltodextrin ABC transporter allows poor growth for the mapP but not the malP mutant. Synthesis of MapP in a B. subtilis mutant accumulating maltose 6'-P restored growth on maltose. MapP catalyses the dephosphorylation of intracellular maltose 6'-P, and the resulting maltose is converted by the B. subtilis maltose phosphorylase into glucose and glucose 1-P. MapP therefore connects PTS-mediated maltose uptake to maltose phosphorylase-catalysed metabolism. Dephosphorylation assays with a wide variety of phospho-substrates revealed that MapP preferably dephosphorylates disaccharides containing an O-α-glycosyl linkage.
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Affiliation(s)
- Abdelhamid Mokhtari
- INRA, Microbiologie de l'alimentation au service de la santé humaine (MICALIS), UMR1319, F-78350, Jouy en Josas, France
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27
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α-Galacturonidase(s): a new class of Family 4 glycoside hydrolases with strict specificity and a unique CHEV active site motif. FEBS Lett 2013; 587:799-803. [PMID: 23416295 DOI: 10.1016/j.febslet.2013.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 01/18/2013] [Accepted: 02/01/2013] [Indexed: 11/20/2022]
Abstract
The catalytic activity of the Family 4 glycosidase LplD protein, whose active site motif is CHEV, is unknown despite its crystal structure having been determined in 2008. Here we identify that activity as being an α-galacturonidase whose natural substrate is probably α-1,4-di-galacturonate (GalUA2). Phylogenetic analysis shows that LplD belongs to a monophyletic clade of CHEV Family 4 enzymes, of which four other members are also shown to be galacturonidases. Family GH 4 enzymes catalyze the cleavage of the glycosidic bond, via a non-canonical redox-assisted mechanism that contrasts with Koshland's double-displacement mechanism.
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28
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Wang J, Mei H, Zheng C, Qian H, Cui C, Fu Y, Su J, Liu Z, Yu Z, He J. The metabolic regulation of sporulation and parasporal crystal formation in Bacillus thuringiensis revealed by transcriptomics and proteomics. Mol Cell Proteomics 2013; 12:1363-76. [PMID: 23408684 DOI: 10.1074/mcp.m112.023986] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bacillus thuringiensis is a well-known entomopathogenic bacterium used worldwide as an environmentally compatible biopesticide. During sporulation, B. thuringiensis accumulates a large number of parasporal crystals consisting of insecticidal crystal proteins (ICPs) that can account for nearly 20-30% of the cell's dry weight. However, the metabolic regulation mechanisms of ICP synthesis remain to be elucidated. In this study, the combined efforts in transcriptomics and proteomics mainly uncovered the following 6 metabolic regulation mechanisms: (1) proteases and the amino acid metabolism (particularly, the branched-chain amino acids) became more active during sporulation; (2) stored poly-β-hydroxybutyrate and acetoin, together with some low-quality substances provided considerable carbon and energy sources for sporulation and parasporal crystal formation; (3) the pentose phosphate shunt demonstrated an interesting regulation mechanism involving gluconate when CT-43 cells were grown in GYS medium; (4) the tricarboxylic acid cycle was significantly modified during sporulation; (5) an obvious increase in the quantitative levels of enzymes and cytochromes involved in energy production via the electron transport system was observed; (6) most F0F1-ATPase subunits were remarkably up-regulated during sporulation. This study, for the first time, systematically reveals the metabolic regulation mechanisms involved in the supply of amino acids, carbon substances, and energy for B. thuringiensis spore and parasporal crystal formation at both the transcriptional and translational levels.
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Affiliation(s)
- Jieping Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PRC
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29
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Abstract
From a generated PES, one can determine the relative energies of species involved, the sequence in which they occur, and the activation barrier(s) associated with individual steps or the overall mechanism. Furthermore, they can provide more insights than a simple indication of a path of sequential mechanistic structures and their energetic relationships. The investigation into the activation of O2 by alpha-ketoglutarate-dependent dioxygenase (AlkB) clearly shows the opportunity for spin inversion, where one can see that the lowest energy product may be formed via several possible routes. In the investigation of uroporphyrinogen decarboxylase III (UROD), the use of QM/MM methods allowed for the inclusion of the anisotropic protein environment providing greater insight into the rate-limiting barrier. Lastly, the mechanism of 6-phospho-α-glucosidase (GlvA) was discussed using different active site models. In particular, a continuum model PES was compared to the gas-phase PES.
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30
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Yip VLY, Withers SG. Identification of Tyr241 as a key catalytic base in the family 4 glycoside hydrolase BglT from Thermotoga maritima. Biochemistry 2012; 51:8464-74. [PMID: 23025815 DOI: 10.1021/bi301021u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While the vast majority of glycosidases catalyze glycoside hydrolysis via oxocarbenium ion-like transition states and typically employ carboxylic acid residues as acid/base or nucleophile catalysts, two subfamilies of these enzymes (GH4 and GH109 in the CAZY classification) conduct hydrolysis via a redox-assisted mechanism involving anionic transition states. While good evidence of this mechanism has been obtained, the identities of the catalytic residues involved have not yet been confirmed. Mechanistic analyses of mutants of the 6-phospho-β-glucosidase from Thermotoga maritima (BglT), in which the active site tyrosine residue (Tyr 241) has been replaced with Phe and Ala, provide support for its role as a catalytic base. The pH dependence of k(cat) and k(cat)/K(m), particularly of the acidic limb corresponding to the base, is shifted relative to that of the wild-type enzyme. Kinetic isotope effects for hydrolysis of substrates deuterated at C1, C2, and C3 by the Tyr 241 mutants are strongly pH-dependent, with essentially full primary kinetic isotope effects being observed for the 2-deutero substrate at low pH with the Tyr241Ala mutant. This is consistent with a slowing of the deprotonation step upon removal of the base.
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Affiliation(s)
- Vivian L Y Yip
- 2036 Main Mall, Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z1
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31
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Jongkees SAK, Withers SG. Glycoside Cleavage by a New Mechanism in Unsaturated Glucuronyl Hydrolases. J Am Chem Soc 2011; 133:19334-7. [DOI: 10.1021/ja209067v] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Seino A. K. Jongkees
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Stephen G. Withers
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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32
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Thompson J, Pikis A. Metabolism of sugars by genetically diverse species of oral Leptotrichia. Mol Oral Microbiol 2011; 27:34-44. [PMID: 22230464 DOI: 10.1111/j.2041-1014.2011.00627.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Leptotrichia buccalis ATCC 14201 is a gram-negative, anaerobic rod-shaped bacterium resident in oral biofilm at the tooth surface. The sequenced genome of this organism reveals three contiguous genes at loci: Lebu_1525, Lebu_1526 and Lebu_1527. The translation products of these genes exhibit significant homology with phospho-α-glucosidase (Pagl), a regulatory protein (GntR) and a phosphoenol pyruvate-dependent sugar transport protein (EIICB), respectively. In non-oral bacterial species, these genes comprise the sim operon that facilitates sucrose isomer metabolism. Growth studies showed that L. buccalis fermented a wide variety of carbohydrates, including four of the five isomers of sucrose. Growth on the isomeric disaccharides elicited expression of a 50-kDa polypeptide comparable in size to that encoded by Lebu_1525. The latter gene was cloned, and the expressed protein was purified to homogeneity from Escherichia coli TOP10 cells. In the presence of two cofactors, NAD(+) and Mn(2+) ions, the enzyme readily hydrolyzed p-nitrophenyl-α-glucopyranoside 6-phosphate (pNPαG6P), a chromogenic analogue of the phosphorylated isomers of sucrose. By comparative sequence alignment, immunoreactivity and signature motifs, the enzyme can be assigned to the phospho-α-glucosidase (Pagl) clade of Family 4 of the glycosyl hydrolase super family. We suggest that the products of Lebu_1527 and Lebu_1525, catalyze the phosphorylative translocation and hydrolysis of sucrose isomers in L. buccalis, respectively. Four genetically diverse, but 16S rDNA-related, species of Leptotrichia have recently been described: L. goodfellowii, L. hofstadii, L. shahii and L. wadei. The phenotypic traits of these new species, with respect to carbohydrate utilization, have also been determined.
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Affiliation(s)
- J Thompson
- Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, NIDCR, National Institutes of Health, Bethesda, MD 20892, USA.
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33
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Chakladar S, Cheng L, Choi M, Liu J, Bennet AJ. Mechanistic Evaluation of MelA α-Galactosidase from Citrobacter freundii: A Family 4 Glycosyl Hydrolase in Which Oxidation Is Rate-Limiting. Biochemistry 2011; 50:4298-308. [DOI: 10.1021/bi101808h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Saswati Chakladar
- Department of Chemistry and ‡Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Lydia Cheng
- Department of Chemistry and ‡Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Mary Choi
- Department of Chemistry and ‡Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - James Liu
- Department of Chemistry and ‡Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Andrew J. Bennet
- Department of Chemistry and ‡Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
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34
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Huang W, Llano J, Gauld JW. Redox mechanism of glycosidic bond hydrolysis catalyzed by 6-phospho-alpha-glucosidase: a DFT study. J Phys Chem B 2010; 114:11196-206. [PMID: 20698522 DOI: 10.1021/jp102399h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glycosidic bonds are remarkably resistant to cleavage by chemical hydrolysis. Glycoside hydrolases catalyze their selective hydrolysis in oligosaccharides, polysaccharides, and glycoconjugates by following nonredox catalytic pathways or a net redox-neutral catalytic pathway using NAD(+) and divalent metal ions as cofactors. GlvA (6-phospho-alpha-glucosidase) is a glycosidase belonging to family GH4 and follows a regioselective redox-neutral mechanism of glycosidic-bond hydrolysis that favors alpha- over beta-glycosides. Its proposed catalytic mechanism can be divided into two half-reactions: the first one activates the glucopyranose ring by successively forming intermediates that are oxidized at the 3-, 2-, and 1-positions of the ring, which ultimately facilitate the heterolytic deglycosylation. The second half-reaction is essentially the reverse of the first half-reaction, beginning with the pyranose ring hydroxylation at the anomeric carbon, and it is followed by 3-reduction and regeneration of the active forms of the catalytic site and its cofactors. We investigated the NAD(+)-dependent redox mechanism of glycosidic bond hydrolysis as catalyzed by GlvA through the combined application of density functional theory and a self-consistent reaction field to a large active-site model obtained from the crystallographic structure of the enzyme, then we applied natural bond orbital and second-order perturbation analyses to monitor the electron flow and change in oxidation state on each atomic center along the reaction coordinate to rationalize the energetics and regioselectivity of this catalytic mechanism. We find that in GlvA, the redox catalytic mechanism of hydrolysis is driven by the gradual strengthening of the axial endo-anomeric component within the hexose ring along the reaction coordinate to facilitate the heterolytic dissociation of the axial C1-O bond. In addition, the combined influence of specific components of the generalized anomeric effect fully explains the regioselectivity observed in the catalytic activity of GlvA.
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Affiliation(s)
- Wenjuan Huang
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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35
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Vuong TV, Wilson DB. Glycoside hydrolases: catalytic base/nucleophile diversity. Biotechnol Bioeng 2010; 107:195-205. [PMID: 20552664 DOI: 10.1002/bit.22838] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent studies have shown that a number of glycoside hydrolase families do not follow the classical catalytic mechanisms, as they lack a typical catalytic base/nucleophile. A variety of mechanisms are used to replace this function, including substrate-assisted catalysis, a network of several residues, and the use of non-carboxylate residues or exogenous nucleophiles. Removal of the catalytic base/nucleophile by mutation can have a profound impact on substrate specificity, producing enzymes with completely new functions.
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Affiliation(s)
- Thu V Vuong
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
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36
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Maltose and maltodextrin utilization by Listeria monocytogenes depend on an inducible ABC transporter which is repressed by glucose. PLoS One 2010; 5:e10349. [PMID: 20436965 PMCID: PMC2860498 DOI: 10.1371/journal.pone.0010349] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 04/07/2010] [Indexed: 01/19/2023] Open
Abstract
Background In the environment as well as in the vertebrate intestine, Listeriae have access to complex carbohydrates like maltodextrins. Bacterial exploitation of such compounds requires specific uptake and utilization systems. Methodology/Principal Findings We could show that Listeria monocytogenes and other Listeria species contain genes/gene products with high homology to the maltodextrin ABC transporter and utilization system of B. subtilis. Mutant construction and growth tests revealed that the L. monocytogenes gene cluster was required for the efficient utilization of maltodextrins as well as maltose. The gene for the ATP binding protein of the transporter was located distant from the cluster. Transcription analyses demonstrated that the system was induced by maltose/maltodextrins and repressed by glucose. Its induction was dependent on a LacI type transcriptional regulator. Repression by glucose was independent of the catabolite control protein CcpA, but was relieved in a mutant defective for Hpr kinase/phosphorylase. Conclusions/Significance The data obtained show that in L. monocytogenes the uptake of maltodextrin and, in contrast to B. subtilis, also maltose is exclusively mediated by an ABC transporter. Furthermore, the results suggest that glucose repression of the uptake system possibly is by inducer exclusion, a mechanism not described so far in this organism.
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Hall BG, Pikis A, Thompson J. Evolution and biochemistry of family 4 glycosidases: implications for assigning enzyme function in sequence annotations. Mol Biol Evol 2009; 26:2487-97. [PMID: 19625389 DOI: 10.1093/molbev/msp162] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Glycosyl hydrolase Family 4 (GH4) is exceptional among the 114 families in this enzyme superfamily. Members of GH4 exhibit unusual cofactor requirements for activity, and an essential cysteine residue is present at the active site. Of greatest significance is the fact that members of GH4 employ a unique catalytic mechanism for cleavage of the glycosidic bond. By phylogenetic analysis, and from available substrate specificities, we have assigned a majority of the enzymes of GH4 to five subgroups. Our classification revealed an unexpected relationship between substrate specificity and the presence, in each subgroup, of a motif of four amino acids that includes the active-site Cys residue: alpha-glucosidase, CHE(I/V); alpha-galactosidase, CHSV; alpha-glucuronidase, CHGx; 6-phospho-alpha-glucosidase, CDMP; and 6-phospho-beta-glucosidase, CN(V/I)P. The question arises: Does the presence of a particular motif sufficiently predict the catalytic function of an unassigned GH4 protein? To test this hypothesis, we have purified and characterized the alpha-glucoside-specific GH4 enzyme (PalH) from the phytopathogen, Erwinia rhapontici. The CHEI motif in this protein has been changed by site-directed mutagenesis, and the effects upon substrate specificity have been determined. The change to CHSV caused the loss of all alpha-glucosidase activity, but the mutant protein exhibited none of the anticipated alpha-galactosidase activity. The Cys-containing motif may be suggestive of enzyme specificity, but phylogenetic placement is required for confidence in that specificity. The Acholeplasma laidlawii GH4 protein is phylogenetically a phospho-beta-glucosidase but has a unique SSSP motif. Lacking the initial Cys in that motif it cannot hydrolyze glycosides by the normal GH4 mechanism because the Cys is required to position the metal ion for hydrolysis, nor can it use the more common single or double-displacement mechanism of Koshland. Several considerations suggest that the protein has acquired a new function as the consequence of positive selection. This study emphasizes the importance of automatic annotation systems that by integrating phylogenetic analysis, functional motifs, and bioinformatics data, may lead to innovative experiments that further our understanding of biological systems.
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Affiliation(s)
- Barry G Hall
- Bellingham Research Institute, Bellingham, WA, USA.
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38
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Vocadlo DJ, Davies GJ. Mechanistic insights into glycosidase chemistry. Curr Opin Chem Biol 2009; 12:539-55. [PMID: 18558099 DOI: 10.1016/j.cbpa.2008.05.010] [Citation(s) in RCA: 300] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 05/19/2008] [Indexed: 11/16/2022]
Abstract
The enzymatic hydrolysis of the glycosidic bond continues to gain importance, reflecting the critically important roles complex glycans play in health and disease as well as the rekindled interest in enzymatic biomass conversion. Recent advances include the broadening of our understanding of enzyme reaction coordinates, through both computational and structural studies, improved understanding of enzyme inhibition through transition state mimicry and fascinating insights into mechanism yielded by physical organic chemistry approaches.
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Affiliation(s)
- David J Vocadlo
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, Canada.
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39
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Nagarajan S, Mohan Das T, Arjun P, Raaman N. Design, synthesis and gelation studies of 4,6-O-butylidene-α,β-unsaturated-β-C-glycosidic ketones: application to plant tissue culture. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b902064k] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Nagarajan S, Mohan Das T. A sugar–pyrene-based fluorescent gelator: nanotubular architecture and interaction with SWCNTs. NEW J CHEM 2009. [DOI: 10.1039/b9nj00395a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Kluger R, Rathgeber S. Catalyzing separation of carbon dioxide in thiamin diphosphate-promoted decarboxylation. FEBS J 2008; 275:6089-100. [DOI: 10.1111/j.1742-4658.2008.06739.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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42
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Transient oxidation as a mechanistic strategy in enzymatic catalysis. Curr Opin Chem Biol 2008; 12:532-8. [DOI: 10.1016/j.cbpa.2008.06.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Accepted: 06/17/2008] [Indexed: 11/18/2022]
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43
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The sim operon facilitates the transport and metabolism of sucrose isomers in Lactobacillus casei ATCC 334. J Bacteriol 2008; 190:3362-73. [PMID: 18310337 DOI: 10.1128/jb.02008-07] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inspection of the genome sequence of Lactobacillus casei ATCC 334 revealed two operons that might dissimilate the five isomers of sucrose. To test this hypothesis, cells of L. casei ATCC 334 were grown in a defined medium supplemented with various sugars, including each of the five isomeric disaccharides. Extracts prepared from cells grown on the sucrose isomers contained high levels of two polypeptides with M(r)s of approximately 50,000 and approximately 17,500. Neither protein was present in cells grown on glucose, maltose or sucrose. Proteomic, enzymatic, and Western blot analyses identified the approximately 50-kDa protein as an NAD(+)- and metal ion-dependent phospho-alpha-glucosidase. The oligomeric enzyme was purified, and a catalytic mechanism is proposed. The smaller polypeptide represented an EIIA component of the phosphoenolpyruvate-dependent sugar phosphotransferase system. Phospho-alpha-glucosidase and EIIA are encoded by genes at the LSEI_0369 (simA) and LSEI_0374 (simF) loci, respectively, in a block of seven genes comprising the sucrose isomer metabolism (sim) operon. Northern blot analyses provided evidence that three mRNA transcripts were up-regulated during logarithmic growth of L. casei ATCC 334 on sucrose isomers. Internal simA and simF gene probes hybridized to approximately 1.5- and approximately 1.3-kb transcripts, respectively. A 6.8-kb mRNA transcript was detected by both probes, which was indicative of cotranscription of the entire sim operon.
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