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Veldman W, Liberato MV, Almeida VM, Souza VP, Frutuoso MA, Marana SR, Moses V, Tastan Bishop Ö, Polikarpov I. X-ray Structure, Bioinformatics Analysis, and Substrate Specificity of a 6-Phospho-β-glucosidase Glycoside Hydrolase 1 Enzyme from Bacillus licheniformis. J Chem Inf Model 2020; 60:6392-6407. [PMID: 33166469 DOI: 10.1021/acs.jcim.0c00759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In bacteria, mono- and disaccharides are phosphorylated during the uptake processes through the vastly spread transport system phosphoenolpyruvate-dependent phosphotransferase. As an initial step in the phosphorylated disaccharide metabolism pathway, 6-phospho-β-glucosidases and 6-phospho-β-galactosidases play a crucial role by releasing phosphorylated and nonphosphorylated monosaccharides. However, structural determinants for the specificity of these enzymes still need to be clarified. Here, an X-ray structure of a glycoside hydrolase family 1 enzyme from Bacillus licheniformis, hereafter known as BlBglH, was determined at 2.2 Å resolution, and its substrate specificity was investigated. The sequence of BlBglH was compared to the sequences of 58 other GH1 enzymes using sequence alignments, sequence identity calculations, phylogenetic analysis, and motif discovery. Through these various analyses, BlBglH was found to have sequence features characteristic of the 6-phospho-β-glucosidase activity enzymes. Motif and structural observations highlighted the importance of loop L8 in 6-phospho-β-glucosidase activity enzymes. To further affirm enzyme specificity, molecular docking and molecular dynamics simulations were performed using the crystallographic structure of BlBglH. Docking was carried out with a 6-phospho-β-glucosidase enzyme activity positive and negative control ligand, followed by 400 ns of MD simulations. The positive and negative control ligands were PNP6Pglc and PNP6Pgal, respectively. PNP6Pglc maintained favorable interactions within the active site until the end of the MD simulation, while PNP6Pgal exhibited instability. The favorable binding of substrate stabilized the loops that surround the active site. Binding free energy calculations showed that the PNP6Pglc complex had a substantially lower binding energy compared to the PNP6Pgal complex. Altogether, the findings of this study suggest that BlBglH possesses 6-phospho-β-glucosidase enzymatic activity and revealed sequence and structural differences between bacterial GH1 enzymes of various activities.
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Affiliation(s)
- Wayde Veldman
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa
| | | | - Vitor M Almeida
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000 São Paulo, Brazil
| | - Valquiria P Souza
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000 São Paulo, Brazil
| | - Maira A Frutuoso
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000 São Paulo, Brazil
| | - Sandro R Marana
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000 São Paulo, Brazil
| | - Vuyani Moses
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, Brazil
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2
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Shulami S, Zehavi A, Belakhov V, Salama R, Lansky S, Baasov T, Shoham G, Shoham Y. Cross-utilization of β-galactosides and cellobiose in Geobacillus stearothermophilus. J Biol Chem 2020; 295:10766-10780. [PMID: 32493770 DOI: 10.1074/jbc.ra120.014029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/02/2020] [Indexed: 11/06/2022] Open
Abstract
Strains of the Gram-positive, thermophilic bacterium Geobacillus stearothermophilus possess elaborate systems for the utilization of hemicellulolytic polysaccharides, including xylan, arabinan, and galactan. These systems have been studied extensively in strains T-1 and T-6, representing microbial models for the utilization of soil polysaccharides, and many of their components have been characterized both biochemically and structurally. Here, we characterized routes by which G. stearothermophilus utilizes mono- and disaccharides such as galactose, cellobiose, lactose, and galactosyl-glycerol. The G. stearothermophilus genome encodes a phosphoenolpyruvate carbohydrate phosphotransferase system (PTS) for cellobiose. We found that the cellobiose-PTS system is induced by cellobiose and characterized the corresponding GH1 6-phospho-β-glucosidase, Cel1A. The bacterium also possesses two transport systems for galactose, a galactose-PTS system and an ABC galactose transporter. The ABC galactose transport system is regulated by a three-component sensing system. We observed that both systems, the sensor and the transporter, utilize galactose-binding proteins that also bind glucose with the same affinity. We hypothesize that this allows the cell to control the flux of galactose into the cell in the presence of glucose. Unexpectedly, we discovered that G. stearothermophilus T-1 can also utilize lactose and galactosyl-glycerol via the cellobiose-PTS system together with a bifunctional 6-phospho-β-gal/glucosidase, Gan1D. Growth curves of strain T-1 growing in the presence of cellobiose, with either lactose or galactosyl-glycerol, revealed initially logarithmic growth on cellobiose and then linear growth supported by the additional sugars. We conclude that Gan1D allows the cell to utilize residual galactose-containing disaccharides, taking advantage of the promiscuity of the cellobiose-PTS system.
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Affiliation(s)
- Smadar Shulami
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Arie Zehavi
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Valery Belakhov
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rachel Salama
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shifra Lansky
- Institute of Chemistry and the Laboratory for Structural Chemistry and Biology, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Timor Baasov
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel
| | - Gil Shoham
- Institute of Chemistry and the Laboratory for Structural Chemistry and Biology, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yuval Shoham
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
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3
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Lansky S, Zehavi A, Belrhali H, Shoham Y, Shoham G. Structural basis for enzyme bifunctionality – the case of Gan1D fromGeobacillus stearothermophilus. FEBS J 2017; 284:3931-3953. [DOI: 10.1111/febs.14283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/31/2017] [Accepted: 09/28/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Shifra Lansky
- Institute of Chemistry The Laboratory for Structural Chemistry and Biology The Hebrew University of Jerusalem Israel
| | - Arie Zehavi
- Department of Biotechnology and Food Engineering Technion ‐ Israel Institute of Technology Haifa Israel
| | | | - Yuval Shoham
- Department of Biotechnology and Food Engineering Technion ‐ Israel Institute of Technology Haifa Israel
| | - Gil Shoham
- Institute of Chemistry The Laboratory for Structural Chemistry and Biology The Hebrew University of Jerusalem Israel
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4
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Ogorzalek TL, Wei S, Liu Y, Wang Q, Brooks CL, Chen Z, Marsh ENG. Molecular-Level Insights into Orientation-Dependent Changes in the Thermal Stability of Enzymes Covalently Immobilized on Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:6145-53. [PMID: 25973638 DOI: 10.1021/acs.langmuir.5b01735] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Surface-immobilized enzymes are important for a wide range of technological applications, including industrial catalysis, drug delivery, medical diagnosis, and biosensors; however, our understanding of how enzymes and proteins interact with abiological surfaces on the molecular level remains extremely limited. We have compared the structure, activity, and thermal stability of two variants of a β-galactosidase attached to a chemically well-defined maleimide-terminated self-assembled monolayer surface through a unique cysteinyl residue. In one case the enzyme is attached through an α helix and in the other case through an adjacent loop. Both enzymes exhibit similar specific activities and adopt similar orientations with respect to the surface normal, as determined by sum-frequency generation and attenuated total reflectance FT-IR spectroscopies. Surprisingly, however, the loop-tethered enzyme exhibits a thermal stability 10 °C lower than the helix-tethered enzyme and 13 °C lower than the enzyme in free solution. Using coarse-grain models, molecular dynamics simulations of the thermal unfolding of the surface-tethered enzymes were able to reproduce these differences in stability. Thus, revealing that tethering through the more flexible loop position provides more opportunity for surface residues on the protein to interact with the surface and undergo surface-induced unfolding. These observations point to the importance of the location of the attachment point in determining the performance of surface-supported biocatalysts and suggest strategies for optimizing their activity and thermal stability through molecular simulations.
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Affiliation(s)
- Tadeusz L Ogorzalek
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Shuai Wei
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Yuwei Liu
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Quiming Wang
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Charles L Brooks
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- §Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- ‡Department of Macromolecular Science and Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, United States
| | - E Neil G Marsh
- †Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
- ∥Department of Biological Chemistry, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109, United States
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Motif-guided identification of a glycoside hydrolase family 1 α-L-arabinofuranosidase in Bifidobacterium adolescentis. Biosci Biotechnol Biochem 2013; 77:1709-14. [PMID: 23924734 DOI: 10.1271/bbb.130279] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Members of glycoside hydrolase family 1 (GH1) cleave glycosidic linkages with a variety of physiological roles. Here we report a unique GH1 member encoded in the genome of Bifidobacterium adolescentis ATCC 15703. This enzyme, BAD0156, was identified from over 2,000 GH1 sequences accumulated in a database by a genome mining approach based on a motif sequence. A recombinant BAD0156 protein was characterized to confirm that this enzyme alone specifically hydrolyzes p-nitrophenyl-α-L-arabinofuranoside among the 24 p-nitrophenyl-glycosides examined. Among natural glycosides, α-1,5-linked arabino-oligosaccharides served as substrates, but arabinan, debranched arabinan, arabinoxylan, and arabinogalactan did not. A time course analysis of arabino-oligosaccharide hydrolysis indicated that BAD0156 is an exo-acting enzyme. These results suggest that BAD0156 is an α-L-arabinofuranosidase. This is the first report of a GH1 enzyme that acts specifically on arabinosides, providing information on GH1 substrate specificity.
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Michalska K, Tan K, Li H, Hatzos-Skintges C, Bearden J, Babnigg G, Joachimiak A. GH1-family 6-P-β-glucosidases from human microbiome lactic acid bacteria. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:451-63. [PMID: 23519420 PMCID: PMC3605045 DOI: 10.1107/s0907444912049608] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/03/2012] [Indexed: 11/11/2022]
Abstract
In lactic acid bacteria and other bacteria, carbohydrate uptake is mostly governed by phosphoenolpyruvate-dependent phosphotransferase systems (PTSs). PTS-dependent translocation through the cell membrane is coupled with phosphorylation of the incoming sugar. After translocation through the bacterial membrane, the β-glycosidic bond in 6'-P-β-glucoside is cleaved, releasing 6-P-β-glucose and the respective aglycon. This reaction is catalyzed by 6-P-β-glucosidases, which belong to two glycoside hydrolase (GH) families: GH1 and GH4. Here, the high-resolution crystal structures of GH1 6-P-β-glucosidases from Lactobacillus plantarum (LpPbg1) and Streptococcus mutans (SmBgl) and their complexes with ligands are reported. Both enzymes show hydrolytic activity towards 6'-P-β-glucosides. The LpPbg1 structure has been determined in an apo form as well as in a complex with phosphate and a glucose molecule corresponding to the aglycon molecule. The S. mutans homolog contains a sulfate ion in the phosphate-dedicated subcavity. SmBgl was also crystallized in the presence of the reaction product 6-P-β-glucose. For a mutated variant of the S. mutans enzyme (E375Q), the structure of a 6'-P-salicin complex has also been determined. The presence of natural ligands enabled the definition of the structural elements that are responsible for substrate recognition during catalysis.
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Affiliation(s)
- Karolina Michalska
- Midwest Center for Structural Genomics, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA
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Genome mining and motif modifications of glycoside hydrolase family 1 members encoded by Geobacillus kaustophilus HTA426 provide thermostable 6-phospho-β-glycosidase and β-fucosidase. Appl Microbiol Biotechnol 2012; 97:2929-38. [DOI: 10.1007/s00253-012-4168-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/11/2012] [Accepted: 05/10/2012] [Indexed: 10/28/2022]
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8
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Francl AL, Hoeflinger JL, Miller MJ. Identification of lactose phosphotransferase systems in Lactobacillus gasseri ATCC 33323 required for lactose utilization. Microbiology (Reading) 2012; 158:944-952. [DOI: 10.1099/mic.0.052928-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Alyssa L. Francl
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jennifer L. Hoeflinger
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Michael J. Miller
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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9
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Vilei EM, Correia I, Ferronha MH, Bischof DF, Frey J. Beta-D-glucoside utilization by Mycoplasma mycoides subsp. mycoides SC: possible involvement in the control of cytotoxicity towards bovine lung cells. BMC Microbiol 2007; 7:31. [PMID: 17439646 PMCID: PMC1855930 DOI: 10.1186/1471-2180-7-31] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 04/17/2007] [Indexed: 12/20/2022] Open
Abstract
Background Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides small-colony type (SC) is among the most serious threats for livestock producers in Africa. Glycerol metabolism-associated H2O2 production seems to play a crucial role in virulence of this mycoplasma. A wide number of attenuated strains of M. mycoides subsp. mycoides SC are currently used in Africa as live vaccines. Glycerol metabolism is not affected in these vaccine strains and therefore it does not seem to be the determinant of their attenuation. A non-synonymous single nucleotide polymorphism (SNP) in the bgl gene coding for the 6-phospho-β-glucosidase (Bgl) has been described recently. The SNP differentiates virulent African strains isolated from outbreaks with severe CBPP, which express the Bgl isoform Val204, from strains to be considered less virulent isolated from CBPP outbreaks with low mortality and vaccine strains, which express the Bgl isoform Ala204. Results Strains of M. mycoides subsp. mycoides SC considered virulent and possessing the Bgl isoform Val204, but not strains with the Bgl isoform Ala204, do trigger elevated levels of damage to embryonic bovine lung (EBL) cells upon incubation with the disaccharides (i.e., β-D-glucosides) sucrose and lactose. However, strains expressing the Bgl isoform Val204 show a lower hydrolysing activity on the chromogenic substrate p-nitrophenyl-β-D-glucopyranoside (pNPbG) when compared to strains that possess the Bgl isoform Ala204. Defective activity of Bgl in M. mycoides subsp. mycoides SC does not lead to H2O2 production. Rather, the viability during addition of β-D-glucosides in medium-free buffers is higher for strains harbouring the Bgl isoform Val204 than for those with the isoform Ala204. Conclusion Our results indicate that the studied SNP in the bgl gene is one possible cause of the difference in bacterial virulence among strains of M. mycoides subsp. mycoides SC. Bgl does not act as a direct virulence factor, but strains possessing the Bgl isoform Val204 with low hydrolysing activity are more prone to survive in environments that contain high levels of β-D-glucosides, thus contributing in some extent to mycoplasmaemia.
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Affiliation(s)
- Edy M Vilei
- Institute of Veterinary Bacteriology, University of Bern, Länggass-Strasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Ivone Correia
- Laboratório Nacional de Investigação Veterinária, Departamento de Biologia Celular, Estrada de Benfica 701, P-1549-011 Lisbon, Portugal
| | - M Helena Ferronha
- Laboratório Nacional de Investigação Veterinária, Departamento de Biologia Celular, Estrada de Benfica 701, P-1549-011 Lisbon, Portugal
| | - Daniela F Bischof
- Institute of Veterinary Bacteriology, University of Bern, Länggass-Strasse 122, Postfach, CH-3001 Bern, Switzerland
| | - Joachim Frey
- Institute of Veterinary Bacteriology, University of Bern, Länggass-Strasse 122, Postfach, CH-3001 Bern, Switzerland
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Old LA, Lowes S, Russell RRB. Genomic variation in Streptococcus mutans: deletions affecting the multiple pathways of β-glucoside metabolism. ACTA ACUST UNITED AC 2006; 21:21-7. [PMID: 16390337 DOI: 10.1111/j.1399-302x.2005.00246.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The genome of Streptococcus mutans UA159 contains two phospho-beta-glucosidase genes, bglA and celA, which occur in operon-like arrangements along with genes for components of phosphotransferase transport systems and a third phospho-beta-glucosidase encoded by the arb gene, which does not have its own associated transport system but relies on uptake by the bgl or cel systems. Targeted inactivation of each of the phospho-beta-glucosidase genes revealed that bglA is involved in aesculin hydrolysis, celA is essential for utilisation of cellobiose, amygdalin, gentobiose and salicin, and arb is required for utilisation of arbutin. Inactivation of genes for the phosphotransferase systems revealed an overlap of specificity for transport of beta-glucosides and also indicated that further, unidentified transport systems exist. The cel and arb genes are subject to catabolite repression by glucose, but the regM gene is not essential for catabolite repression. Screening a collection of isolates of S. mutans revealed strains with deletions affecting the msm, bgl and/or cel operons. The phenotypes of these strains could largely be explained on the basis of the results obtained from the knockout mutants of S. mutans UA159 but also indicated the existence of other pathways apparently absent from UA159. The extensive genetic and phenotypic variation found in beta-glucoside metabolism indicates that there may be extensive heterogeneity in the species.
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Affiliation(s)
- L A Old
- Oral Biology, School of Dental Sciences, University of Newcastle, Newcastle upon Tyne, UK
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Kim BJ, Mangala SL, Hayashi K. Co-refolding of two peptide fragments derived from Agrobacterium tumefaciens
β-glucosidase with catalytic activity. FEBS Lett 2005; 579:3075-80. [PMID: 15907844 DOI: 10.1016/j.febslet.2005.04.065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 04/06/2005] [Accepted: 04/15/2005] [Indexed: 10/25/2022]
Abstract
Four sites of the non-homologous region (coding amino acid residues of 347, 421, 466 and 533) of a gene were randomly selected for splitting to investigate the function of beta-glucosidase from Agrobacterium tumefaciens in the co-refolding of peptides into the catalytically active enzyme. As a result of gene splitting, four N- and C-terminal domain peptides were obtained as insoluble inclusion bodies. No catalytic activity was observed when these fragments refolded individually. However, a considerable amount of activity was restored when the two fragments derived from N- and C- terminal peptides were co-refolded together. The deletion of amino acid residues in the non-homologous region resulted in a complete loss of enzyme activity, which suggests that truncation of amino acids in this region strongly affects the co-refolding ability of the enzyme to maintain activity.
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Affiliation(s)
- Bong-Jo Kim
- Enzyme Laboratory, National Food Research Institute, 2-1-12 Kannondai, Tsukuba 305-8642, Japan.
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12
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Hancock SM, Corbett K, Fordham-Skelton AP, Gatehouse JA, Davis BG. Developing Promiscuous Glycosidases for Glycoside Synthesis: Residues W433 and E432 in Sulfolobus solfataricus β-Glycosidase are Important Glucoside- and Galactoside-Specificity Determinants. Chembiochem 2005; 6:866-75. [PMID: 15846595 DOI: 10.1002/cbic.200400341] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Two residues that have been implicated in determining the substrate specificity of the thermophilic beta-glycosidase from the archaeon Sulfolobus solfataricus (SsbetaG), a member of the glycosyl hydrolase family 1, have been mutated by site-directed mutagenesis so as to create more versatile catalysts for carbohydrate chemistry. The wild-type and mutated sequences were expressed in E. coli with a His(7)-tag to allow one-step chromatographic purification. The E432C and W433C mutations removed key interactions with the OH-4 and OH-3 of the sugar substrates, thus reducing the discrimination of glucose, galactose and fucose with respect to other glycosides. This resulted in two glycosidases with greatly broadened substrate specificities. Observed changes include a 24-fold increase in Man:Gal activity and an 18-fold increase in GalA:Gal activity. This promiscuous substrate tolerance was further illustrated by the parallel synthesis of a beta-glycoside library of glucose, galactose, xylose and mannose in one pot at 50 degrees C, in organic solvent. The synthetic potential of the catalysts was further evaluated through alkyl glycoside transglycosylation yields, including the first examples of synthesis of beta-mannosides and beta-xylosides with SsbetaG.
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Affiliation(s)
- Susan M Hancock
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
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Marana SR, Andrade EHP, Ferreira C, Terra WR. Investigation of the substrate specificity of a beta-glycosidase from Spodoptera frugiperda using site-directed mutagenesis and bioenergetics analysis. ACTA ACUST UNITED AC 2004; 271:4169-77. [PMID: 15511222 DOI: 10.1111/j.1432-1033.2004.04354.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The specificity of the Spodoptera frugiperda digestive beta-glycosidase (Sfbetagly50) for fucosides, glucosides and galactosides is determined by noncovalent interactions of glycone 6-OH and glycone 4-OH with the active-site residues Q39 and E451. Site-directed mutagenesis and enzyme steady-state kinetics were described, showing that replacement of E451 with glutamine increased the preference of Sfbetagly50 for glucosides in comparison to galactosides, whereas replacing E451 with serine had the opposite effect. In contrast, the replacement of E451 with aspartate did not change Sfbetagly50 specificity. The energy of the interactions formed by these different residues with the axial and equatorial glycone 4-OH were also measured, showing that the increase in preference for galactosides resulted from a larger energy decrease in the interaction with equatorial 4-OH than with axial 4-OH (22.6 vs. 13.9 kJ x mol(-1)), whereas the increase in preference for glucosides was caused by an energy reduction in the interaction with the axial 4-OH (5.1 kJ x mol(-1)). The introduction of glutamine at position 451 or of asparagine at position 39 increased the preference of Sfbetagly50 for fucosides in comparison to galactosides, whereas the presence of aspartate or serine at position 451 had less effect on this preference. The hydrolysis of fucosides was favored because glutamine at position 451 increased a steric hindrance with 6-OH of 7.1 kJ x mol(-1) and asparagine at position 39 disrupted a favorable interaction with this same hydroxyl. In conclusion, it is proposed that the specificity of new beta-glycosidase mutants can be predicted by combining and adding energy of the enzyme-substrate interactions evaluated in the present study.
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Affiliation(s)
- Sandro R Marana
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
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