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Li SF, Cheng F, Wang YJ, Zheng YG. Strategies for tailoring pH performances of glycoside hydrolases. Crit Rev Biotechnol 2023; 43:121-141. [PMID: 34865578 DOI: 10.1080/07388551.2021.2004084] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glycoside hydrolases (GHs) exhibit high activity and stability under harsh conditions, such as high temperatures and extreme pHs, given their wide use in industrial biotechnology. However, strategies for improving the acidophilic and alkalophilic adaptations of GHs are poorly summarized due to the complexity of the mechanisms of these adaptations. This review not only highlights the adaptation mechanisms of acidophilic and alkalophilic GHs under extreme pH conditions, but also summarizes the recent advances in engineering the pH performances of GHs with a focus on four strategies of protein engineering, enzyme immobilization, chemical modification, and medium engineering (additives). The examples described here summarize the methods used in modulating the pH performances of GHs and indicate that methods integrated in different protein engineering techniques or methods are efficient to generate industrial biocatalysts with the desired pH performance and other adapted enzyme properties.
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Affiliation(s)
- Shu-Fang Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China.,Engineering Research Center of Bioconversion and Biopurification of the Ministry of Education, Zhejiang University of Technology, Hangzhou, Zhejiang, P. R. China.,The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Feng Cheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China.,Engineering Research Center of Bioconversion and Biopurification of the Ministry of Education, Zhejiang University of Technology, Hangzhou, Zhejiang, P. R. China.,The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Ya-Jun Wang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China.,Engineering Research Center of Bioconversion and Biopurification of the Ministry of Education, Zhejiang University of Technology, Hangzhou, Zhejiang, P. R. China.,The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China.,Engineering Research Center of Bioconversion and Biopurification of the Ministry of Education, Zhejiang University of Technology, Hangzhou, Zhejiang, P. R. China.,The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, P. R. China
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2
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KANEKO R, MORI T, KATAYAMA Y. Signal Amplification Enzymes for Bioanalysis of Cells and Tissues. BUNSEKI KAGAKU 2022. [DOI: 10.2116/bunsekikagaku.71.101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Ryosuke KANEKO
- Department of Applied Chemistry, Faculty of Engineering, Kyushu University
| | - Takeshi MORI
- Department of Applied Chemistry, Faculty of Engineering, Kyushu University
| | - Yoshiki KATAYAMA
- Department of Applied Chemistry, Faculty of Engineering, Kyushu University
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3
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Bwanali L, Crihfield CL, Newton EO, Zeger VR, Gattu S, Holland LA. Quantification of the α2-6 Sialic Acid Linkage in Branched N-Glycan Structures with Capillary Nanogel Electrophoresis. Anal Chem 2020; 92:1518-1524. [PMID: 31829566 PMCID: PMC8631463 DOI: 10.1021/acs.analchem.9b04787] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sialylation and sialic acid linkage in N-glycans are markers of disease but are analytically challenging to quantify. A capillary electrophoresis method is reported that integrates a unique combination of enzymes and lectins to modify sialylated N-glycans in real time in the capillary so that N-glycan structures containing α2-6-linked sialic acid are easily separated, detected, and quantified. In this study, N-glycans were sequentially cleaved by enzymes at the head of the separation capillary so that the presence of α2-6-linked sialic acids corresponded to a shift in the analyte migration time in a manner that enabled interpretation of the N-glycan structure. Following injection, only afucosylated N-glycan structures were passed through enzyme zones that contained α2-3 sialidase, followed by β1-3,4 galactosidase, which cleaved any terminal α2-3-linked sialic acid and underlying galactose yielding a terminal N-acetyl glucosamine. With this treatment complete, a third zone of α2-3,6,8 sialidase converted the remaining α2-6-linked sialic acid to terminal galactose. With these enzyme processing steps the α2-6-linked sialic acid residues on an N-glycan correlated directly to the number of terminal galactose residues that remained. The number of terminal galactose residues could be interpreted as a stepwise decrease in the migration time. Complex N-glycans from α-1-acid glycoprotein were analyzed using this approach, revealing that a limited number of α2-6-linked sialic acids were present with biantennary, triantennary, and tetraantennary N-glycans of α-1-acid glycoprotein generally containing 0 or 1 α2-6-linked sialic acid.
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Affiliation(s)
- Lloyd Bwanali
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Cassandra L. Crihfield
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Ebenezer O. Newton
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Victoria R. Zeger
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Srikanth Gattu
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Lisa A. Holland
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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Casimero C, Bigham T, McGlynn RJ, Dooley JS, Ternan NG, Snelling WJ, Critchley ME, Zinkel CL, Smith RB, Sabogal-Paz LP, Davis J. Electroanalytical properties of chlorophenol red at disposable carbon electrodes: Implications for Escherichia coli detection. Bioelectrochemistry 2019; 130:107321. [DOI: 10.1016/j.bioelechem.2019.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 10/26/2022]
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5
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β-sheet to α-helix conversion and thermal stability of β-Galactosidase encapsulated in a nanoporous silica gel. Biochem Biophys Res Commun 2019; 508:270-274. [DOI: 10.1016/j.bbrc.2018.11.077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/03/2018] [Accepted: 11/12/2018] [Indexed: 11/19/2022]
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6
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Functional Characterization of a New Cold-Adapted β-Galactosidase from an Arctic Fjord Sediment Bacteria Enterobacter ludwigii MCC 3423. Catal Letters 2018. [DOI: 10.1007/s10562-018-2504-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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7
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Jendresen C, Daws MR, Nilsson LNG. An improved CPRG colorimetric ligand-receptor signal transduction assay based on beta-galactosidase activity in mammalian BWZ-reporter cells. J Pharmacol Toxicol Methods 2017; 90:67-75. [PMID: 29203451 DOI: 10.1016/j.vascn.2017.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/23/2017] [Accepted: 11/29/2017] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Reporter cells expressing a chimeric receptor that activates a reporter can be used for screening ligand-mediated signal transduction. In this study, we used reporter cells harboring an NFAT/lacZ construct that express β-galactosidase when the chimeric receptor is stimulated. A colorimetric β-galactosidase substrate, chlorophenol-red β-d-galactopyranoside (CPRG), was used to detect enzymatic activity. Sub-optimal conditions have unfortunately extensively been reported with such reporter-based β-galactosidase assays. Here, we aimed to improve the CPRG-based colorimetric assay such that receptor ligands could be effectively screened with reporter cells. METHODS After stimulation of reporter cells, we determined β-galactosidase activity by absorbance measurement of β-galactosidase-dependent CPRG hydrolysis. We systematically examined each component in a standard lysis buffer most commonly reported for this type of reporter cells. Furthermore, we evaluated literature in the field. RESULTS An increased CPRG substrate concentration combined with a different detergent, Saponin, and an optimal wavelength recording markedly increased the sensitivity for the detection of β-galactosidase activity (≈4-fold increase). Moreover, the improved protocol resulted in increased linear time-dependent recording of enzymatic activity once cells had been lysed, and a more stable and reproducible assay to detect a ligand-stimulus with the reporter cells. The optimal time length of exposure to a stimulus was ligand-dependent. DISCUSSION In conclusion, we provide an improved protocol with an optimized lysis buffer that gives up to a six-fold higher and more robust specific signal when NFAT/lacZ-based receptor-expressing reporter cells are exposed to a stimulus.
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Affiliation(s)
- Charlotte Jendresen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316 Blindern, Oslo, Norway.
| | - Michael R Daws
- Division of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Postboks 1105 Blindern, 0317 Oslo, Norway.
| | - Lars N G Nilsson
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316 Blindern, Oslo, Norway.
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Cheng S, Wu Q, Xiao H, Chen H. Online Monitoring of Enzymatic Reactions Using Time-Resolved Desorption Electrospray Ionization Mass Spectrometry. Anal Chem 2017; 89:2338-2344. [DOI: 10.1021/acs.analchem.6b03975] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Si Cheng
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
| | - Qiuhua Wu
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
- Department
of Chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, China
| | - He Xiao
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
| | - Hao Chen
- Center
for Intelligent Chemical Instrumentation, Department of Chemistry
and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, United States,
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Determination of lactose in milk products: a comparison of three-enzyme amperometric biosensor and gas chromatography/tandem mass spectrometry. MONATSHEFTE FUR CHEMIE 2017. [DOI: 10.1007/s00706-016-1903-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Wang D, Chen J, Nugen SR. Electrochemical Detection of Escherichia coli from Aqueous Samples Using Engineered Phages. Anal Chem 2017; 89:1650-1657. [DOI: 10.1021/acs.analchem.6b03752] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Danhui Wang
- Department
of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department
of Food Science, Cornell University, Ithaca, New York 14853, United States
| | - Juhong Chen
- Department
of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department
of Food Science, Cornell University, Ithaca, New York 14853, United States
| | - Sam R. Nugen
- Department
of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department
of Food Science, Cornell University, Ithaca, New York 14853, United States
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11
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Burgos MI, Velasco MI, Acosta RH, Perillo MA. Environmental Topology and Water Availability Modulates the Catalytic Activity of β-Galactosidase Entrapped in a Nanosporous Silicate Matrix. Sci Rep 2016; 6:36593. [PMID: 27811995 PMCID: PMC5095660 DOI: 10.1038/srep36593] [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: 07/01/2016] [Accepted: 10/17/2016] [Indexed: 02/02/2023] Open
Abstract
In the present work we studied the catalytic activity of E. coli β-Gal confined in a nanoporous silicate matrix (Eβ-Gal) at different times after the beginning of the sol-gel polymerization process. Enzyme kinetic experiments with two substrates (ONPG and PNPG) that differed in the rate-limiting steps of the reaction mechanism for their β-Gal-catalyzed hydrolysis, measurements of transverse relaxation times (T2) of water protons through 1H-NMR, and scanning electron microscopy analysis of the gel nanostructure, were performed. In conjunction, results provided evidence that water availability is crucial for the modulation observed in the catalytic activity of β-Gal as long as water participate in the rate limiting step of the reaction (only with ONPG). In this case, a biphasic rate vs. substrate concentration was obtained exhibiting one phase with catalytic rate constant (kcA), similar to that observed in solution, and another phase with a higher and aging-dependent catalytic rate constant (kcB). More structured water populations (lower T2) correlates with higher catalytic rate constants (kcB). The T2-kcB negative correlation observed along the aging of gels within the 15-days period assayed reinforces the coupling between water structure and the hydrolysis catalysis inside gels.
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Affiliation(s)
- M Ines Burgos
- IIByT-UNC CONICET. Cátedra de Química Biológica, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba. Av. Vélez Sársfield 1611, X5016GCA Córdoba, Argentina
| | - Manuel I Velasco
- IFEG-UNC CONICET. FaMAF-Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
| | - Rodolfo H Acosta
- IFEG-UNC CONICET. FaMAF-Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
| | - María A Perillo
- IIByT-UNC CONICET. Cátedra de Química Biológica, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba. Av. Vélez Sársfield 1611, X5016GCA Córdoba, Argentina
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Anraku Y, Kishimura A, Kamiya M, Tanaka S, Nomoto T, Toh K, Matsumoto Y, Fukushima S, Sueyoshi D, Kano MR, Urano Y, Nishiyama N, Kataoka K. Systemically Injectable Enzyme‐Loaded Polyion Complex Vesicles as In Vivo Nanoreactors Functioning in Tumors. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201508339] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yasutaka Anraku
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
| | - Akihiro Kishimura
- Faculty of Engineering, Center for Molecular Systems (CMS) Kyushu University 744, Moto-oka Nishi-ku, Fukuoka 819-0395 Japan
| | - Mako Kamiya
- Graduate School of Medicine The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 Japan
| | - Sayaka Tanaka
- Graduate School of Medicine, Dentistry, and Pharmaceutical Science Okayama University 1-1-1 Tsushima-naka Kita-ku, Okayama 700–8530 Japan
| | - Takahiro Nomoto
- Polymer Chemistry Division, Chemical Resources Laboratory Tokyo Institute of Technology 4259 Nagatsuta Midori-ku, Yokohama 226–8503 Japan
| | - Kazuko Toh
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine The University of Tokyo Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033 Japan
| | - Yu Matsumoto
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine The University of Tokyo Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033 Japan
| | - Shigeto Fukushima
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
| | - Daiki Sueyoshi
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
| | - Mitsunobu R. Kano
- Graduate School of Medicine, Dentistry, and Pharmaceutical Science Okayama University 1-1-1 Tsushima-naka Kita-ku, Okayama 700–8530 Japan
| | - Yasuteru Urano
- Graduate School of Medicine The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 Japan
| | - Nobuhiro Nishiyama
- Polymer Chemistry Division, Chemical Resources Laboratory Tokyo Institute of Technology 4259 Nagatsuta Midori-ku, Yokohama 226–8503 Japan
| | - Kazunori Kataoka
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine The University of Tokyo Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033 Japan
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Anraku Y, Kishimura A, Kamiya M, Tanaka S, Nomoto T, Toh K, Matsumoto Y, Fukushima S, Sueyoshi D, Kano MR, Urano Y, Nishiyama N, Kataoka K. Systemically Injectable Enzyme‐Loaded Polyion Complex Vesicles as In Vivo Nanoreactors Functioning in Tumors. Angew Chem Int Ed Engl 2015; 55:560-5. [DOI: 10.1002/anie.201508339] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 11/02/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Yasutaka Anraku
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
| | - Akihiro Kishimura
- Faculty of Engineering, Center for Molecular Systems (CMS) Kyushu University 744, Moto-oka Nishi-ku, Fukuoka 819-0395 Japan
| | - Mako Kamiya
- Graduate School of Medicine The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 Japan
| | - Sayaka Tanaka
- Graduate School of Medicine, Dentistry, and Pharmaceutical Science Okayama University 1-1-1 Tsushima-naka Kita-ku, Okayama 700–8530 Japan
| | - Takahiro Nomoto
- Polymer Chemistry Division, Chemical Resources Laboratory Tokyo Institute of Technology 4259 Nagatsuta Midori-ku, Yokohama 226–8503 Japan
| | - Kazuko Toh
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine The University of Tokyo Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033 Japan
| | - Yu Matsumoto
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine The University of Tokyo Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033 Japan
| | - Shigeto Fukushima
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
| | - Daiki Sueyoshi
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
| | - Mitsunobu R. Kano
- Graduate School of Medicine, Dentistry, and Pharmaceutical Science Okayama University 1-1-1 Tsushima-naka Kita-ku, Okayama 700–8530 Japan
| | - Yasuteru Urano
- Graduate School of Medicine The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033 Japan
| | - Nobuhiro Nishiyama
- Polymer Chemistry Division, Chemical Resources Laboratory Tokyo Institute of Technology 4259 Nagatsuta Midori-ku, Yokohama 226–8503 Japan
| | - Kazunori Kataoka
- Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku, Tokyo 113–8656 Japan
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine The University of Tokyo Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033 Japan
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Bello-Gil D, Maestro B, Fonseca J, Feliu JM, Climent V, Sanz JM. Specific and reversible immobilization of proteins tagged to the affinity polypeptide C-LytA on functionalized graphite electrodes. PLoS One 2014; 9:e87995. [PMID: 24498237 PMCID: PMC3909327 DOI: 10.1371/journal.pone.0087995] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/02/2014] [Indexed: 11/19/2022] Open
Abstract
We have developed a general method for the specific and reversible immobilization of proteins fused to the choline-binding module C-LytA on functionalized graphite electrodes. Graphite electrode surfaces were modified by diazonium chemistry to introduce carboxylic groups that were subsequently used to anchor mixed self-assembled monolayers consisting of N,N-diethylethylenediamine groups, acting as choline analogs, and ethanolamine groups as spacers. The ability of the prepared electrodes to specifically bind C-LytA-tagged recombinant proteins was tested with a C-LytA-β-galactosidase fusion protein. The binding, activity and stability of the immobilized protein was evaluated by electrochemically monitoring the formation of an electroactive product in the enzymatic hydrolysis of the synthetic substrate 4-aminophenyl β-D-galactopyranoside. The hybrid protein was immobilized in an specific and reversible way, while retaining the catalytic activity. Moreover, these functionalized electrodes were shown to be highly stable and reusable. The method developed here can be envisaged as a general, immobilization procedure on the protein biosensor field.
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Affiliation(s)
- Daniel Bello-Gil
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Spain
- Instituto Universitario de Electroquímica. Universidad de Alicante, Alicante, Spain
| | - Beatriz Maestro
- Instituto Universitario de Electroquímica. Universidad de Alicante, Alicante, Spain
| | - Jennifer Fonseca
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Spain
| | - Juan M. Feliu
- Instituto Universitario de Electroquímica. Universidad de Alicante, Alicante, Spain
| | - Víctor Climent
- Instituto Universitario de Electroquímica. Universidad de Alicante, Alicante, Spain
| | - Jesús M. Sanz
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Spain
- * E-mail:
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Electrophoretically mediated microanalysis for in-capillaryelectrical cell lysis and fast enzyme quantification by capillary electrophoresis. Anal Bioanal Chem 2013; 405:9159-67. [DOI: 10.1007/s00216-013-7332-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/23/2013] [Accepted: 08/29/2013] [Indexed: 01/29/2023]
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16
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Didier JE, Schafer CM, LeDuc PR. Programmed Biologically Inspired Synthetic Templating of Multifunctional Nanoarchitectures for Small‐Scale Reactions. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jonathan E. Didier
- Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
| | - Chad M. Schafer
- Department of Statistics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
| | - Philip R. LeDuc
- Departments of Mechanical and Biomedical Engineering, Computational Biology and Biological Sciences, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA, Fax: +1‐412‐268‐3348
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Hossain SMZ, Ozimok C, Sicard C, Aguirre SD, Ali MM, Li Y, Brennan JD. Multiplexed paper test strip for quantitative bacterial detection. Anal Bioanal Chem 2012; 403:1567-76. [DOI: 10.1007/s00216-012-5975-x] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 03/21/2012] [Accepted: 03/26/2012] [Indexed: 11/30/2022]
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18
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Brechbuhl HM, Ghosh M, Smith MK, Smith RW, Li B, Hicks DA, Cole BB, Reynolds PR, Reynolds SD. β-catenin dosage is a critical determinant of tracheal basal cell fate determination. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:367-79. [PMID: 21703416 DOI: 10.1016/j.ajpath.2011.03.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/22/2011] [Accepted: 03/31/2011] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to determine whether β-catenin regulates basal cell fate determination in the mouse trachea. Analysis of TOPGal transgene reporter activity and Wnt/β-catenin pathway gene expression suggested a role for β-catenin in basal cell proliferation and differentiation after naphthalene-mediated Clara-like and ciliated cell depletion. However, these basal cell activities occurred simultaneously, limiting precise determination of the role(s) played by β-catenin. This issue was overcome by analysis of β-catenin signaling in tracheal air-liquid interface cultures. The cultures could be divided into two phases: basal cell proliferation and basal cell differentiation. A role for β-catenin in basal cell proliferation was indicated by activation of the TOPGal transgene on proliferation days 3 to 5 and by transient expression of Myc (alias c-myc). Another peak of TOPGal transgene activity was detected on differentiation days 2 to 10 and was associated with the expression of Axin 2. These results suggest a role for β-catenin in basal to ciliated and basal to Clara-like cell differentiation. Genetic stabilization of β-catenin in basal cells shortened the period of basal cell proliferation but had a minor effect on this process. Persistent β-catenin signaling regulated basal cell fate by driving the generation of ciliated cells and preventing the production of Clara-like cells.
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Activity modulation and reusability of β-d-galactosidase confined in sol–gel derived porous silicate glass. Colloids Surf B Biointerfaces 2010; 76:387-96. [DOI: 10.1016/j.colsurfb.2009.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/03/2009] [Accepted: 11/09/2009] [Indexed: 11/22/2022]
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Juers DH, Rob B, Dugdale ML, Rahimzadeh N, Giang C, Lee M, Matthews BW, Huber RE. Direct and indirect roles of His-418 in metal binding and in the activity of beta-galactosidase (E. coli). Protein Sci 2009; 18:1281-92. [PMID: 19472413 DOI: 10.1002/pro.140] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The active site of ss-galactosidase (E. coli) contains a Mg(2+) ion ligated by Glu-416, His-418 and Glu-461 plus three water molecules. A Na(+) ion binds nearby. To better understand the role of the active site Mg(2+) and its ligands, His-418 was substituted with Asn, Glu and Phe. The Asn-418 and Glu-418 variants could be crystallized and the structures were shown to be very similar to native enzyme. The Glu-418 variant showed increased mobility of some residues in the active site, which explains why the substitutions at the Mg(2+) site also reduce Na(+) binding affinity. The Phe variant had reduced stability, bound Mg(2+) weakly and could not be crystallized. All three variants have low catalytic activity due to large decreases in the degalactosylation rate. Large decreases in substrate binding affinity were also observed but transition state analogs bound as well or better than to native. The results indicate that His-418, together with the Mg(2+), modulate the central role of Glu-461 in binding and as a general acid/base catalyst in the overall catalytic mechanism. Glucose binding as an acceptor was also dramatically decreased, indicating that His-418 is very important for the formation of allolactose (the natural inducer of the lac operon).
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Affiliation(s)
- Douglas H Juers
- Instititute of Molecular Biology, Howard Hughes Medical Institute and Department of Physics, University of Oregon, Eugene, OR 97403-1229, USA
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21
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Hanaoka K, Kikuchi K, Terai T, Komatsu T, Nagano T. A Gd3+-Based Magnetic Resonance Imaging Contrast Agent Sensitive to β-Galactosidase Activity Utilizing a Receptor-Induced Magnetization Enhancement (RIME) Phenomenon. Chemistry 2008; 14:987-95. [DOI: 10.1002/chem.200700785] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Sutendra G, Wong S, Fraser ME, Huber RE. β-Galactosidase (Escherichia coli) has a second catalytically important Mg2+ site. Biochem Biophys Res Commun 2007; 352:566-70. [PMID: 17126292 DOI: 10.1016/j.bbrc.2006.11.061] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Accepted: 11/14/2006] [Indexed: 11/20/2022]
Abstract
It is shown here that Escherichia coli beta-galactosidase has a second Mg2+ binding site that is important for activity. Binding of Mg2+ to the second site caused the k(cat) (with oNPG as the substrate) to increase about 100 s(-1); the Km was not affected. The Kd for binding the second Mg2+ is about 10(-4)M. Since the concentration of free Mg2+ in E. coli is about 1-2 mM, the second site is physiologically significant. Non-polar substitutions (Ala or Leu) for Glu-797, a residue in an active site loop, eliminated the k(cat) increase. This indicates that the second Mg2+ site is near to Glu-797. The Ki values of transition state analogs were decreased by small but statistically significant amounts when the second Mg2+ site was occupied and Arrhenius plots showed that less entropic activation energy is required when the second site is occupied. These inhibitor and temperature results suggest that binding of the second Mg2+ helps to order the active site for stabilization of the transition state.
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Affiliation(s)
- Gopinath Sutendra
- Biochemistry, Faculty of Science, University of Calgary, Calgary, Alta., Canada T2N 1N4
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23
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Flowers HM, Sharon N. Glycosidases--properties and application to the study of complex carbohydrates and cell surfaces. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 48:29-95. [PMID: 367104 DOI: 10.1002/9780470122938.ch2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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24
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Volkov IY, Lunina NA, Berezina OV, Velikodvorskaya GA, Zverlov VV. Thermoanaerobacter ethanolicus Gene Cluster Containing the α- and β-Galactosidase Genes melA and lacA and Properties of Recombinant LacA. Mol Biol 2005. [DOI: 10.1007/s11008-005-0098-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Coker JA, Sheridan PP, Loveland-Curtze J, Gutshall KR, Auman AJ, Brenchley JE. Biochemical characterization of a beta-galactosidase with a low temperature optimum obtained from an Antarctic arthrobacter isolate. J Bacteriol 2003; 185:5473-82. [PMID: 12949099 PMCID: PMC193751 DOI: 10.1128/jb.185.18.5473-5482.2003] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A psychrophilic gram-positive isolate was obtained from Antarctic Dry Valley soil. It utilized lactose, had a rod-coccus cycle, and contained lysine as the diamino acid in its cell wall. Consistent with these physiological traits, the 16S ribosomal DNA sequence showed that it was phylogenetically related to other Arthrobacter species. A gene (bgaS) encoding a family 2 beta-galactosidase was cloned from this organism into an Escherichia coli host. Preliminary results showed that the enzyme was cold active (optimal activity at 18 degrees C and 50% activity remaining at 0 degrees C) and heat labile (inactivated within 10 min at 37 degrees C). To enable rapid purification, vectors were constructed adding histidine residues to the BgaS enzyme and its E. coli LacZ counterpart, which was purified for comparison. The His tag additions reduced the specific activities of both beta-galactosidases but did not alter the other characteristics of the enzymes. Kinetic studies using o-nitrophenyl-beta-D-galactopyranoside showed that BgaS with and without a His tag had greater catalytic activity at and below 20 degrees C than the comparable LacZ beta-galactosidases. The BgaS heat lability was investigated by ultracentrifugation, where the active enzyme was a homotetramer at 4 degrees C but dissociated into inactive monomers at 25 degrees C. Comparisons of family 2 beta-galactosidase amino acid compositions and modeling studies with the LacZ structure did not mimic suggested trends for conferring enzyme flexibility at low temperatures, consistent with the changes affecting thermal adaptation being localized and subtle. Mutation studies of the BgaS enzyme should aid our understanding of such specific, localized changes affecting enzyme thermal properties.
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Affiliation(s)
- James A Coker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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26
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Leahy M, Vaughan P, Fanning L, Fanning S, Sheehan D. Purification and some characteristics of a recombinant dimeric rhizobium meliloti beta-galactosidase expressed in escherichia coli. Enzyme Microb Technol 2001; 28:682-688. [PMID: 11339953 DOI: 10.1016/s0141-0229(01)00314-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A recombinant Rhizobium meliloti beta-galactosidase was purified to homogeneity from an Escherichia coli expression system. The gene for the enzyme was cloned into a pKK223-3 plasmid which was then used to transform E. coli JM109 cells. The enzyme was purified 35-fold with a yield of 34% by a combination of DEAE-cellulose (pH 8.0) and two sequential Mono Q steps (at pH 8.0 and 6.0, respectively). The purified enzyme had an apparent molecular mass of 174 kDa and a subunit molecular weight of 88 kDa, indicating that it is a dimer. It was active with both synthetic substrates p-nitrophenyl beta-D-galactopyranoside (PNPG) and o-nitrophenyl beta-D-galactopyranoside (ONPG) with K(m)(PNPG) and K(m)(ONPG) of 1 mM at 25 degrees C. The k(cat)/K(m) ratios for both substrates were approximately 70 mM(-1) sec(-1), indicating no clear preference for either PNPG or ONPG, unlike E. coli beta-galactosidase. After non-denaturing electrophoresis, active beta-galactosidase bands were identified using 5-bromo-4-chloro-3-indolyl beta-D-galactopyranoside (X-gal) or 6-bromo-2-naphthyl beta-D-galactopyranoside (BNG) and diazo blue B.
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Affiliation(s)
- M Leahy
- Department of Biochemistry, Lee Maltings, Prospect Row, Mardyke, Cork, Ireland
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27
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Pikal-Cleland KA, Rodríguez-Hornedo N, Amidon GL, Carpenter JF. Protein Denaturation during Freezing and Thawing in Phosphate Buffer Systems: Monomeric and Tetrameric β-Galactosidase. Arch Biochem Biophys 2000; 384:398-406. [PMID: 11368330 DOI: 10.1006/abbi.2000.2088] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During freezing in sodium and potassium phosphate (NaP and KP) buffer solutions, changes in pH may impact the stability of proteins. Since the degradation pathways for the model proteins, monomeric and tetrameric beta-galactosidase (beta-gal), chosen for this study are governed by conformational changes (i.e., physical instability) as opposed to chemical transformations, we explored how the stresses of freezing and thawing alter the protein's native structure and if preservation of the native conformation during freeze-thawing is a requisite for optimal recovery of activity. During freezing in NaP buffer, a significant pH decrease from 7.0 to as low as 3.8 was observed due to the selective precipitation of the disodium phosphate; however, the pH during freezing in KP buffer only increased by at most 0.3 pH units. pH-induced inactivation was evident as seen by the lower recovery of activity when freeze-thawing in NaP buffer as compared to KP buffer for both sources of beta-gal. In addition, we investigated the effects of cooling rate and warming rate on the recovery of activity for monomeric and tetrameric beta-gal. Optimal recovery of activity for the NaP samples was obtained when the processing protocol involved a fast cool/fast warm combination, which minimizes exposure to acidic conditions and concentrated solutes. Alterations in the native secondary structure of monomeric beta-gal as measured by infrared spectroscopy were more significant when freezing and thawing in NaP buffer as opposed to KP buffer. Conformational and activity analyses indicate that pH changes during freezing in NaP buffer contribute to denaturation of beta-gal. These results suggest that proteins formulated in NaP buffer should be frozen and thawed rapidly to minimize exposure to low pH and high buffer salts.
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Golan R, Zehavi U, Naim M, Patchornik A, Smirnoff P, Herchman M. Photoreversible modulators of Escherichia coli beta-galactosidase. 1-Benzoyl-1-cyano-2-(4,5-dimethoxy-2-nitrophenyl)-ethene and 1,1-dicyano-2-(4,5-dimethoxy-2-nitrophenyl)-ethene. JOURNAL OF PROTEIN CHEMISTRY 2000; 19:123-8. [PMID: 10945436 DOI: 10.1023/a:1007082516503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Beta-galactosidase (EC 3.2.1.23) is known to be inhibited by some thiol reagents. 1-Benzoyl-1-cyano-2-(4,5-dimethoxy-2-nitrophenyl)-ethene (1) was shown to be an irreversible inhibitor, while 1, 1-dicyano-2-(4,5-dimethoxy-2-nitrophenyl)-ethene (2) was demonstrated as a positive irreversible modulator causing a rise of up to 186% in beta-galactosidase activity. Compound 2 is, however, an irreversible inhibitor of the cysteine proteinase papain (preceding paper). Kinetic values of beta-galactosidase at pH 8.3 with o-nitrophenyl beta-D-galactopyranoside (ONPG) as the substrate and for compounds 1 and 2 were determined and in view of model experiments, it was assumed that both compounds possibly reacted with the thiol side chain of Cys in the active site inducing allosteric changes in the enzyme. Since the enzyme, modified by compound 1 or 2, was a 2-nitrobenzyl derivative, near-UV irradiation resulted in a recovery of up to 91% and a reduction of the enzyme's activity to 90%, respectively.
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Affiliation(s)
- R Golan
- Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
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29
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Kono H, Waelchili MR, Fujiwara M, Erata T, Takai M. Regioselective syntheses of new tri- and tetrasaccharides from β-glucobioses by Trichoderma viride β-glucosidase and their structural analyses by NMR spectroscopy. Carbohydr Res 1999. [DOI: 10.1016/s0008-6215(99)00166-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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30
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Gee KR, Sun WC, Bhalgat MK, Upson RH, Klaubert DH, Latham KA, Haugland RP. Fluorogenic substrates based on fluorinated umbelliferones for continuous assays of phosphatases and beta-galactosidases. Anal Biochem 1999; 273:41-8. [PMID: 10452797 DOI: 10.1006/abio.1999.4202] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fluorogenic substrates based on 4-methylumbelliferone (4-MU) have been widely used for the detection of phosphatase and glycosidase activities. One disadvantage of these substrates, however, is that maximum fluorescence of the reaction product requires an alkaline pH, since 4-MU has a pK(a) approximately 8. In an initial screening of five phosphatase substrates based on fluorinated derivatives of 4-MU, all with pK(a) values lower than that of 4-MU, we found that one substrate, 6,8-difluoro-4-methylumbelliferyl phosphate (DiFMUP), was much improved for the detection of acid phosphatase activity. When measured at the preferred acid phosphatase reaction pH (5.0), DiFMUP yielded fluorescence signals that were more than 10-fold higher than those of 4-methylumbelliferyl phosphate (MUP). DiFMUP was also superior to MUP for the detection of protein phosphatase 1 activity at pH 7 and was just as sensitive as MUP for the detection of alkaline phosphatase activity at pH 10. A beta-galactosidase substrate was also prepared based on 6, 8-difluoro-4-methylumbelliferone. This substrate, 6, 8-difluoro-4-methylumbelliferyl beta-d-galactopyranoside (DiFMUG), was found to be considerably more sensitive than the commonly used substrate 4-methylumbelliferyl beta-d-galactopyranoside (MUG), for the detection of beta-galactosidase activity at pH 7. DiFMUP and DiFMUG should have great utility for the continuous assay of phosphatase and beta-galactosidase activity, respectively, at neutral and acid pH.
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Affiliation(s)
- K R Gee
- Molecular Probes, Incorporated, 4849 Pitchford Avenue, Eugene, Oregon 97402, USA
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31
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Kono H, Kawano S, Tajima K, Erata T, Takai M. Structural analyses of new tri- and tetrasaccharides produced from disaccharides by transglycosylation of purified Trichoderma viride beta-glucosidase. Glycoconj J 1999; 16:415-23. [PMID: 10737327 DOI: 10.1023/a:1007034728857] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A new beta-glucosidase was partially purified from Trichoderma viride cellulase. This beta-glucosidase catalyzed a transglycosylation reaction of cellobiose to give beta-D-Glc-(1-->6)-beta-D-Glc-(1-->4)-D-Glc (1, yield: 18.8%) and beta-D-Glc-(1-->6)-beta-D-Glc-(1-->6)-beta-D-Glc-(1-->4)-D-Glc (2, 3.7%), regioselectively. Furthermore, the enzyme regioselectively converted laminaribiose and gentiobiose into beta-D-Glc-(1-->6)-beta-D-Glc-(1-->3)-D-Glc (3, 15.3%) and beta-D-Glc-(1-->6)-beta-D-Glc-(1-->6)-D-Glc (4, 20.2%), respectively. The structures (1-4) of the products were determined by 1H and 13C NMR spectroscopies. This high regio- and stereoselectively of the beta-glucosidase could be applied for oligosaccharide synthesis.
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Affiliation(s)
- H Kono
- Division of Molecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Japan.
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Sanders JW, Leenhouts K, Burghoorn J, Brands JR, Venema G, Kok J. A chloride-inducible acid resistance mechanism in Lactococcus lactis and its regulation. Mol Microbiol 1998; 27:299-310. [PMID: 9484886 DOI: 10.1046/j.1365-2958.1998.00676.x] [Citation(s) in RCA: 205] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Previously, a promoter was identified in Lactococcus lactis that is specifically induced by chloride. Here, we describe the nucleotide sequence and functional analysis of two genes transcribed from this promoter, gadC and gadB. GadC is homologous to putative glutamate-gamma-aminobutyrate antiporters of Escherichia coli and Shigella flexneri and contains 12 putative membrane-spanning domains. GadB shows similarity to glutamate decarboxylases. A L. lactis gadB mutant and a strain that is unable to express both gadB and gadC was more sensitive to low pH than the wild type when NaCl and glutamate were present. Expression of gadCB in L. lactis in the presence of chloride was increased when the culture pH was allowed to decrease to low levels by omitting buffer from the medium, while glutamate also stimulated gadCB expression. Apparently, these genes encode a glutamate-dependent acid resistance mechanism of L. lactis that is optimally active under conditions in which it is needed to maintain viability. Immediately upstream of the chloride-dependent gadCB promoter Pgad, a third gene encodes a protein (GadR) that is homologous to the activator Rgg from Streptococcus gordonii. gadR expression is chloride and glutamate independent. A gadR mutant did not produce the 3kb gadCB mRNA that is found in wild-type cells in the presence of NaCl, indicating that GadR is an activator of the gadCB operon.
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Affiliation(s)
- J W Sanders
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands
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Zhu G, Nicolson AG, Zheng XX, Strom TB, Sukhatme VP. Adenovirus-mediated beta-galactosidase gene delivery to the liver leads to protein deposition in kidney glomeruli. Kidney Int 1997; 52:992-9. [PMID: 9328938 DOI: 10.1038/ki.1997.421] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The many cell types of the kidney, precisely arranged, allow this organ to perform its complex physiologic functions. However, this architectural complexity makes gene transfer into the kidney difficult. One approach to delivering a therapeutic protein to the kidney is to transfer a gene to a non-renal tissue. Release of the protein into the circulation might then result in deposition in the kidney, if the protein has the appropriate molecular properties. In this study, we found that parenterally administered replication deficient adenovirus carrying the beta-galactosidase gene resulted in intense beta-galactosidase gene expression in hepatocytes. As a result of immune attack on transduced hepatocytes, beta-galactosidase protein from these cells is released into the circulation, transported, and deposited almost exclusively in kidney glomeruli. Intense beta-galactosidase activity was noted in both kidneys with a peak at two weeks following viral administration, concurrent with loss of beta-galactosidase positive hepatocytes. Consistent with our hypothesis of protein transfer, no beta-galactosidase mRNA was detected in glomeruli. Moreover, systemically administered protein generated similar glomerular beta-galactosidase activity. Finally, co-administration of murine CTLA4 Ig, an immunomodulator of T cell activation, with the adenovirus protected infected hepatocytes and markedly diminished glomerular beta-galactosidase activity. Collectively, these findings suggest that a therapeutic protein can be "targeted" to the renal glomerulus, utilizing the liver as a gene transfer organ.
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Affiliation(s)
- G Zhu
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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Huber RE, Roth NJ, Bahl H. Quaternary structure, Mg2+ interactions, and some kinetic properties of the beta-galactosidase from Thermoanaerobacterium thermosulfurigenes EM1. JOURNAL OF PROTEIN CHEMISTRY 1996; 15:621-9. [PMID: 8968953 DOI: 10.1007/bf01886744] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The beta-galactosidase from Thermoanaerobacterium thermosulfurigenes EM1 was found to be a dimer with a monomer molecular weight of about 85,000. It lacks the alpha-peptide and an important alpha-helix that are both needed for dimer-dimer interaction and there is no homology in other important dimer-dimer interaction areas. These differences in structure probably account for the dimeric (rather than tetrameric) structure. Only 0.19 Mg2+ bound per monomer and Mg2+ had only small effects on the activity and heat stability. The absence of residues equivalent to Glu-416 and His-418 (two of the three ligands to Mg2+ in the beta-galactosidase from Escherichia coli) probably accounts for the low level of Mg2+ binding and the consequent lack of response to Mg2+. Both Na+ and K+ also had no effect on the activity. The enzyme activity with o-nitrophenyl-beta-D-galactopyanoside (ONPG) was very similar to that with p-nitrophenyl-beta-D-beta-D-galactopyranoside (PNPG) and the ONPG pH profile was very similar to the PNPG pH profile. These differences are in contrast to the E.coli beta-galactosidase, which dramatically discriminates between these two substrates. The lack of discrimination by the T. thermosulfurigenes beta-galactosidase could be due to the absence of the sequence equivalent to residues 910-1023 of the E. coli beta-galactosidase. Trp-999 is probably of the most importance. Trp-999 of the E. coli beta-galactosidase is important for aglycone binding and ONPG and PNPG differ only in their aglycones. The suggestion that the aglycone site of the T. thermosulfurigenes beta-galactosidase is different was strengthened by competitive inhibition studies. Compared to E. coli beta-galactosidase, D-galactonolactone was a very good inhibitor of the T. thermosulfurigenes enzyme, while L-ribose inhibited poorly. These are transition-state analogs and the results indicate that T. thermosulfurigenes beta-galactosidase binds the transition state differently than does E. coli beta-galactosidase. Methanol and glucose were good acceptors of galactose, and allolactose was formed when glucose was the acceptor. Allolactose could not, however, be detected by TLC when lactose was the substrate. The differences noted may be due to the thermophilic nature of T. thermosulfurigenes.
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Affiliation(s)
- R E Huber
- Division of Biochemistry, Faculty of Science, University of Calgary, Canada.
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35
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Degraeve P, Delorme P, Lemay P. Pressure-induced inactivation of E. coli beta-galactosidase: influence of pH and temperature. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1292:61-8. [PMID: 8547350 DOI: 10.1016/0167-4838(95)00196-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In order to assess the feasibility of a high-pressure immunodesorption process using a beta-galactosidase-anti-beta-galactosidase complex as a model, the influence of high hydrostatic pressure on the activation of E. coli beta-galactosidase has been investigated. The irreversible activity loss of beta-galactosidase was studied as a function of pH and temperature for pressures comprised between atmospheric pressure and 500 megapascal (MPa; 1 MPa = 10 bar). This enabled us to establish a practical pressure-temperature diagram of stability for this enzyme. The stability domains determined thus appeared to be strongly dependent on the pH under atmospheric pressure of phosphate buffer employed for pressurisation. Therefore, to interpret meaningfully this result, the influence of pressure on the pH-activity curve of beta-galactosidase was investigated by using a high-pressure stopped-flow device. It appeared that the pH-activity curve of this enzyme was also reversibly affected by pressures lower than 150 MPa. An interpretation of these results in relation to the high-pressure induced changes of ionisation constants is proposed. For our practical purpose, the implications for the elaboration of a high-pressure immunodesorption process using beta-galactosidase as a tag, are discussed.
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Affiliation(s)
- P Degraeve
- Département de Génie Biochimique et Alimentaire, INSA / DGBA, Toulouse, France
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36
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Martinez-Bilbao M, Huber RE. The activation of beta-galactosidase (E. coli) by Mg(2+) at lower pH values. Biochem Cell Biol 1996; 74:295-8. [PMID: 9213440 DOI: 10.1139/o96-032] [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] [Indexed: 02/04/2023] Open
Abstract
The activation of beta-galactosidase (E. coli) by Mg(2+) at pH values below 7.6 was studied. If the Mg(2+) concentration was high enough, the k(cat) values at pH values down to 5.0 remained at the same high level as at pH 7 and 7.6 (600-620 s-(1) with o-nitrophenyl-beta-D-galactopyranoside as the substrate). Very high concentrations of Mg(2+) (greater than 100 mM at pH 5) were, however, needed to saturate the Mg(2+) site at lower pH values. The Km values at low levels of Mg(2+) were high at every pH but they decreased and approached the same low value at every pH (about 0.13 mM) as the [Mg(2+)] was increased. These data indicate that it is difficult to bind Mg(2+) at lower pH values, but the k(cat) and K(m) values of the enzyme, and therefore the rates of galactosylation (k(2)), degalactosylation (k(3)), and binding (K(s)), do not change substantially as a function of pH provided that a Mg(2+) is bound to the enzyme. The data also showed that Mg(2+) and protons compete for the same site. Analysis by plotting log [Mg(2+)](mid) vs. pH showed that the binding of Mg(2+) to the free enzyme involves two groups with pK(a) values in the vicinity of 7 and one group with a pK(a) value near 5.5. (The values referred to as [Mg(2+)](mid) are the Mg(2+) concentrations that resulted in k(cat) values midway between basal and maximum.) The "apparent" pK(a) values of the groups when a Mg(2+) was bound (at saturating [Mg(2+)]) all appeared to be below 5.0.
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37
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Vishwanath S, Bhattacharyya D, Huang W, Bachas L. Site-directed and random enzyme immobilization on functionalized membranes: kinetic studies and models. J Memb Sci 1995. [DOI: 10.1016/0376-7388(95)00135-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Fieldler F, Hinz H. No intermediate channelling in stepwise hydrolysis of fluorescein di-beta-D-galactoside by beta-galactosidase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 222:75-81. [PMID: 8200355 DOI: 10.1111/j.1432-1033.1994.tb18843.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
For the hydrolysis of the two glycosidic bonds of fluorescein di-beta-D-galactoside (FDG) by beta-galactosidase from Escherichia coli, small [Hofmann, J. & Sernetz, M. (1983) Anal. Biochem. 131, 180-186] to dramatic [Huang, Z. (1991) Biochemistry 30, 8535-8540] deviations from simple stepwise substrate-intermediate-product kinetics have been reported. Intermediate channelling, a preferred hydrolysis of the intermediate fluorescein mono-beta-D-galactoside (FMG) formed from FDG at the active site and thus in a favourable position for further reaction, has been postulated. As there were reasons to doubt the previous findings and conclusions, the hydrolysis experiments have been repeated at initial FDG concentrations of 7-200 microM, following the concentrations of FDG, FMG and fluorescein with a reliable method, quantitative HPLC, to completion of the reaction. The transient appearance of substantial amounts of the intermediate FMG also in experiments with 200 microM FDG already rules out the existence of the most efficient intermediate channelling deduced by Huang (1991) from measurements of the initially developing fluorescence, incorrectly ascribed to fluorescein. Redetermination of the Michaelis constants for FDG and FMG led to much higher values than those reported previously. Fitting the progress curves by means of nonlinear regression combined with numerical integration of the rate equations resulted in good fits of the normal stepwise substrate-intermediate-product mechanism, without any necessity of assuming a more complex course of the reaction. So one of the rare examples of the hydrolysis of two bonds at a single enzyme-substrate encounter has been invalidated.
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Affiliation(s)
- F Fieldler
- Abteilung für Klinische Chemie und Klinische Biochemie, Universität, München, Germany
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39
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Fanning S, Leahy M, Sheehan D. Nucleotide and deduced amino acid sequences of Rhizobium meliloti 102F34 lacZ gene: comparison with prokaryotic beta-galactosidases and human beta-glucuronidase. Gene 1994; 141:91-6. [PMID: 8163182 DOI: 10.1016/0378-1119(94)90133-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The nucleotide (nt) sequence of a 2.57-kb Sau3A fragment carrying the Rhizobium meliloti beta-galactosidase (beta Gal)-encoding gene (RmlacZ) was determined. An open reading frame (ORF) of 2.26 kb was identified which encoded a 755-amino-acid (aa) polypeptide with a calculated molecular mass of 84,141 Da, in fair agreement with the value of 88 kDa determined by SDS-PAGE. The deduced N-terminal aa sequence was confirmed by direct sequencing of electrophoretically purified R. meliloti beta Gal. The size of the native R. meliloti beta Gal was approx. 174 kDa. Similarities were found between the aa sequence of the R. meliloti beta Gal and those from Clostridium thermosulfurogenes EM1 and Agrobacterium radiobacter, as well as human beta-glucuronidase (beta Glu). Comparisons with beta Gal from Escherichia coli, Klebsiella pneumoniae, Lactobacillus bulgaricus and Kluyveromyces lactis found only weak similarities; however, the putative active site residues appear to be conserved. The RmlacZ sequence is flanked by two partially sequenced ORFs, which show aa sequence and organisational similarities to the previously reported lac operon in A. radiobacter.
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Affiliation(s)
- S Fanning
- Medical Sciences Department, Regional Technical College, Bishopstown, Cork, Ireland
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40
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Huber RE, Gupta MN, Khare SK. The active site and mechanism of the beta-galactosidase from Escherichia coli. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1994; 26:309-18. [PMID: 8187928 DOI: 10.1016/0020-711x(94)90051-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- R E Huber
- Division of Biochemistry, Faculty of Science, University of Calgary, Alberta, Canada
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41
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BeMiller JN, Gilson RJ, Myers RW, Santoro MM. Suicide-substrate inactivation of beta-galactosidase by diazomethyl beta-D-galactopyranosyl ketone. Carbohydr Res 1993; 250:101-12. [PMID: 8143286 DOI: 10.1016/0008-6215(93)84159-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Diazomethyl beta-D-galactopyranosyl ketone (1) has been proven to be a mechanism-based, irreversible (suicide-substrate) inactivator of Aspergillus oryzae beta-D-galactosidase, but not an inactivator of E. coli lacZ beta-D-galactosidase. Compound 1 is stable in buffers of normal physiological pH. It is decomposed by H+, but not by nucleophiles. Inactivation of A. oryzae beta-D-galactopyranosyl ketone (2) nor diazomethyl alpha-D-galactopyranosyl ketone inactivated the enzyme and therefore inactivation is stereospecific, excess inhibitor could be separated from inactive enzyme without regain of activity and therefore it is bound irreversibly, and a second pulse of enzyme is inactivated at the same rate as enzyme inactivated to 95% activity by the first pulse. Diazomethyl beta-D-glucopyranosyl ketone (2) inhibited sweet almond beta-D-glucosidase.
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Affiliation(s)
- J N BeMiller
- Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, Indiana 47907
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42
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Heiber-Langer I, Banzet N, Saldana JL, Lemay P, Balny C. Thermodynamic study of β-galactosidase for high pressure separation processes. ACTA ACUST UNITED AC 1993. [DOI: 10.1007/bf02566156] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Corey PF. A new chromogenic beta-galactosidase substrate based on the redox indicator dye ‘methyl purple’. Bioorg Med Chem Lett 1993. [DOI: 10.1016/s0960-894x(01)80871-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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44
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Huber RE, Lehmann J, Ziser L. A bireactant, irreversible, active-site-directed inhibitor of beta-D-galactosidase (Escherichia coli). Synthesis and properties of (1/2,5,6)-2-(3-azibutylthio)-5,6-epoxy-3-cyclohexen-1-ol. Carbohydr Res 1991; 214:35-41. [PMID: 1954632 DOI: 10.1016/s0008-6215(00)90528-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
(1/2,5,6)-2-(3-Azibutylthio)-5,6-epoxy-3-cyclohexen-1-ol (1) was synthesized and was found to irreversibly inactivate beta-D-galactosidase (Escherichia coli). The inactivation was prevented by the presence of isopropyl 1-thio-beta-D-galactopyranoside (IPTG). The vinyloxirane group of 1 reacted with water and other nucleophiles, especially at higher pH values. Reaction of 1 with beta-D-galactosidase was slow enough so that a competitive-inhibition constant (Ki) of 29mM could be determined. The inhibition constant for (1,2/3,6)-6-(3-azibutylthio)-2-bromo-4-cyclohexene-1,3-diol (2), the precursor of the bireactant inhibitor 1, was 13 mM, while that of (1,3/2,4)-3-(3-azibutylthio)-5-cyclohexene-1,2,4-triol (3), the product formed when the reactant is allowed to react with water, was 23mM. After irradiation by light, beta-D-galactosidase that had initially been treated with the bireactant compound and then digested with trypsin, showed a new pattern of elution from h.p.l.c., indicating that there was reaction at two regions of the beta-D-galactosidase molecule.
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Affiliation(s)
- R E Huber
- Division of Biochemistry, Faculty of Science, University of Calgary, Alberta, Canada
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45
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A highly reactive beta-galactosidase (Escherichia coli) resulting from a substitution of an aspartic acid for Gly-794. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67745-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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46
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Ring M, Huber RE. Multiple replacements establish the importance of tyrosine-503 in beta-galactosidase (Escherichia coli). Arch Biochem Biophys 1990; 283:342-50. [PMID: 2125820 DOI: 10.1016/0003-9861(90)90652-f] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tyr-503 of beta-galactosidase was specifically replaced with Phe, His, Cys, and Lys using site-directed mutagenesis. The normal enzyme and the substituted enzymes were purified. The activities of each of the substituted enzymes with o-nitrophenyl-beta-D-galactopyranoside (ONPG) and p-nitrophenyl-beta-D-galactopyronoside (PNPG) were very low and Y503K-beta-galactosidase was essentially inactive, showing that Tyr-503 is important for activity. The stability (including tetrameric stability) of the enzymes at 4 and 25 degrees C was essentially the same as that of the wild-type enzyme and the cleavage patterns on sodium dodecyl sulfate gels after protease action were unchanged. These studies thus indicate that Tyr-503 has no noticeable influence on stability under normal conditions. The substitutions for Tyr-503 had some small effects on the binding of both substrate and inhibitor. However, both kappa 2 (glycosidic bond cleavage rate) and kappa 3 (hydrolysis rate constant) were dramatically reduced. Each substitution except that of Lys (which can be explained by electrostatic effects) gave decreases in kappa 2 and kappa 3 of roughly the same magnitude regardless of whether the substitutions were conservative or not. This strongly implies that the changes in rate were not due to conformational changes as it is very unlikely that there would be such similar decreases in the values of kappa 2 and kappa 3 for amino acids with such different structures and chemical properties if the changes in rate were due to conformational differences. The data suggest that one possible role of Tyr-503 is as a general acid/base catalyst. Profiles of the kinetic data of the enzymes as functions of pH supported the suggestion that Tyr-503 normally acts as a general acid and base catalyst. When Tyr-503 was substituted by His, a small amount of base catalytic activity seemed to be restored. The strongest evidence that Tyr-503 acts as an acid catalyst came from studies with isoquinolinium-beta-D-galactopyranoside as the substrate. The kappa cat(s) of Y503F-beta-galactosidase and of Y503C-beta-galactosidase decreased by about an order of magnitude while the rate decreases were about 3 orders of magnitude with ONPG and PNPG. The breakdown of isoquinolinium-beta-D-galactopyranoside cannot be catalyzed by acids.
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Affiliation(s)
- M Ring
- Division of Biochemistry, Faculty of Science, University of Calgary, Alberta, Canada
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47
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Edwards RA, Cupples CG, Huber RE. Site specific mutants of beta-galactosidase show that Tyr-503 is unimportant in Mg2+ binding but that Glu-461 is very important and may be a ligand to Mg2+. Biochem Biophys Res Commun 1990; 171:33-7. [PMID: 2118347 DOI: 10.1016/0006-291x(90)91352-s] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The Mg2+ concentrations required for half maximal activity, the dissociation constants, and the free energies of binding for Mg2+ bound to wild type beta-galactosidase and several site specific mutants are reported. The mutants have one of the following substitutions: Glu-461 substituted with Asp, Gln, Gly, His, or Lys; or Tyr-503 substituted with Phe, His or Cys. Substitutions for Tyr-503 had little effect on the affinity of the enzyme for Mg2+, implying that Tyr-503 is not involved in Mg2+ binding. Neutrally charged amino acids substituted for the negatively charged Glu-461 significantly decreased the affinity of the enzyme for Mg2+ and substitution of positively charged amino acids at this position further decreased the affinity. On the other hand, substitution by Asp (negative charge) at position 461 had no effect on the binding. Thus, the negatively charged side chain of Glu-461 is important for divalent cation binding to beta-galactosidase.
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Affiliation(s)
- R A Edwards
- Division of Biochemistry, Faculty of Science, University of Calgary, Alberta, Canada
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48
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Selwood T, Sinnott ML. A solvent-isotope-effect study of proton transfer during catalysis by Escherichia coli (lacZ) beta-galactosidase. Biochem J 1990; 268:317-23. [PMID: 2114090 PMCID: PMC1131434 DOI: 10.1042/bj2680317] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
1. Michaelis-Menten parameters for the hydrolysis of 4-nitrophenyl beta-D-galactopyranoside and 3,4-dinitrophenyl beta-D-galactopyranoside Escherichia coli (lacZ) beta-galactosidase were measured as a function of pH or pD (pL) in both 1H2O and 2H2O. 2. For hydrolysis of 4-nitrophenyl beta-D-galactopyranoside by Mg2(+)-free enzyme, V is pL-independent below pL 9, but the V/Km-pL profile is sigmoid, the pK values shifting from 7.6 +/- 0.1 in 1H2O to 8.2 +/- 0.1 in 2H2O, and solvent kinetic isotope effects are negligible, in accord with the proposal [Sinnott, Withers & Viratelle (1978) Biochem. J. 175, 539-546] that glycone-aglycone fission without acid catalysis governs both V and V/Km. 3. V for hydrolysis of 4-nitrophenyl beta-D-galactopyranoside by Mg2(+)-enzyme varies sigmoidally with pL, the pK value shifting from 9.19 +/- 0.09 to 9.70 +/- 0.07; V/Km shows both a low-pL fall, probably due to competition between Mg2+ and protons [Tenu, Viratelle, Garnier & Yon (1971) Eur. J. Biochem. 20, 363-370], and a high-pL fall, governed by a pK that shifts from 8.33 +/- 0.08 to 8.83 +/- 0.08. There is a negligible solvent kinetic isotope effect on V/Km, but one of 1.7 on V, which a linear proton inventory shows to arise from one transferred proton. 4. The variation of V and V/Km with pL is sigmoid for hydrolysis of 3,4-dinitrophenyl beta-D-galactopyranoside by Mg2(+)-enzyme, with pK values showing small shifts, from 8.78 +/- 0.09 to 8.65 +/- 0.08 and from 8.7 +/- 0.1 to 8.9 +/- 0.1 respectively. There is no solvent isotope effect on V or V/Km for 3,4-dinitrophenyl beta-D-galactopyranoside, despite hydrolysis of the galactosyl-enzyme intermediate governing V. 5. Identification of the 'conformation change' in the hydrolysis of aryl galactosides proposed by Sinnott & Souchard [(1973) Biochem. J. 133, 89-98] with the protolysis of the magnesium phenoxide arising from the action of enzyme-bound Mg2+ as an electrophilic catalyst rationalizes these data and also resolves the conflict between the proposals and the 18O kinetic-isotope-effect data reported by Rosenberg & Kirsch [(1981) Biochemistry 20, 3189-3196]. It should be noted that the actual Km values were determined to higher precision than can be estimated from the Figures in this paper.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- T Selwood
- Department of Organic Chemistry, University of Bristol, U.K
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49
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Cupples CG, Miller JH, Huber RE. Determination of the roles of Glu-461 in beta-galactosidase (Escherichia coli) using site-specific mutagenesis. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39391-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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50
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Legler G. Glycoside hydrolases: mechanistic information from studies with reversible and irreversible inhibitors. Adv Carbohydr Chem Biochem 1990; 48:319-84. [PMID: 2077872 DOI: 10.1016/s0065-2318(08)60034-7] [Citation(s) in RCA: 476] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- G Legler
- Institut für Biochemie, Universität Köln, Federal Republic of Germany
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