1
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Calvert M, Sweeney RP, Chen HM, Bajwa H, Nasseri SA, Habibi D, Withers SG. Branched montbretin A mimics allow derivatisation and potent amylase inhibition. Org Biomol Chem 2023; 21:7977-7983. [PMID: 37751159 DOI: 10.1039/d3ob01051a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Mimics of the complex flavonol glycoside montbretin A in which a flavonol moiety is coupled to a caffeic acid via partially peptidic linkers have proved to be potent inhibitors of human pancreatic alpha-amylase with potential as therapeutics for control of blood glucose levels. After exploring optimal linker length, a synthetic route to a version with a branched linker was devised based on the structure of the enzyme/inhibitor complex. The resultant branched inhibitors were shown to retain nanomolar potency even when decorated with polymers as a means of modifying solubility. Similar improvements, along with nanomolar affinity, could also be achieved through conjugation to cyclodextrins which have the potential to bind to starch binding sites found on the surface of human amylase. Incorporation of a conjugatable branch into this unusual pharmacophore thereby affords considerable flexibility for further modifications to improve pharmacokinetic behaviour or as a site for attachment of capture tags or fluorophores.
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Affiliation(s)
- Matthew Calvert
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada.
| | - Ryan P Sweeney
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada.
| | - Hong-Ming Chen
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada.
| | - Harbir Bajwa
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada.
| | - Seyed A Nasseri
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada.
| | - Davood Habibi
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, 6517838683, Iran
| | - Stephen G Withers
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada.
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2
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Tian Y, Wang Y, Zhong Y, Møller MS, Westh P, Svensson B, Blennow A. Interfacial Catalysis during Amylolytic Degradation of Starch Granules: Current Understanding and Kinetic Approaches. Molecules 2023; 28:molecules28093799. [PMID: 37175208 PMCID: PMC10180094 DOI: 10.3390/molecules28093799] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Enzymatic hydrolysis of starch granules forms the fundamental basis of how nature degrades starch in plant cells, how starch is utilized as an energy resource in foods, and develops efficient, low-cost saccharification of starch, such as bioethanol and sweeteners. However, most investigations on starch hydrolysis have focused on its rates of degradation, either in its gelatinized or soluble state. These systems are inherently more well-defined, and kinetic parameters can be readily derived for different hydrolytic enzymes and starch molecular structures. Conversely, hydrolysis is notably slower for solid substrates, such as starch granules, and the kinetics are more complex. The main problems include that the surface of the substrate is multifaceted, its chemical and physical properties are ill-defined, and it also continuously changes as the hydrolysis proceeds. Hence, methods need to be developed for analyzing such heterogeneous catalytic systems. Most data on starch granule degradation are obtained on a long-term enzyme-action basis from which initial rates cannot be derived. In this review, we discuss these various aspects and future possibilities for developing experimental procedures to describe and understand interfacial enzyme hydrolysis of native starch granules more accurately.
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Affiliation(s)
- Yu Tian
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Yu Wang
- Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Yuyue Zhong
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Marie Sofie Møller
- Applied Molecular Enzyme Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Peter Westh
- Interfacial Enzymology, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Birte Svensson
- Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Andreas Blennow
- Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
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3
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Auiewiriyanukul W, Saburi W, Ota T, Yu J, Kato K, Yao M, Mori H. Alteration of Substrate Specificity and Transglucosylation Activity of GH13_31 α-Glucosidase from Bacillus sp. AHU2216 through Site-Directed Mutagenesis of Asn258 on β→α Loop 5. Molecules 2023; 28:molecules28073109. [PMID: 37049872 PMCID: PMC10096246 DOI: 10.3390/molecules28073109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023] Open
Abstract
α-Glucosidase catalyzes the hydrolysis of α-d-glucosides and transglucosylation. Bacillus sp. AHU2216 α-glucosidase (BspAG13_31A), belonging to the glycoside hydrolase family 13 subfamily 31, specifically cleaves α-(1→4)-glucosidic linkages and shows high disaccharide specificity. We showed previously that the maltose moiety of maltotriose (G3) and maltotetraose (G4), covering subsites +1 and +2 of BspAG13_31A, adopts a less stable conformation than the global minimum energy conformation. This unstable d-glucosyl conformation likely arises from steric hindrance by Asn258 on β→α loop 5 of the catalytic (β/α)8-barrel. In this study, Asn258 mutants of BspAG13_31A were enzymatically and structurally analyzed. N258G/P mutations significantly enhanced trisaccharide specificity. The N258P mutation also enhanced the activity toward sucrose and produced erlose from sucrose through transglucosylation. N258G showed a higher specificity to transglucosylation with p-nitrophenyl α-d-glucopyranoside and maltose than the wild type. E256Q/N258G and E258Q/N258P structures in complex with G3 revealed that the maltose moiety of G3 bound at subsites +1 and +2 adopted a relaxed conformation, whereas a less stable conformation was taken in E256Q. This structural difference suggests that stabilizing the G3 conformation enhances trisaccharide specificity. The E256Q/N258G-G3 complex formed an additional hydrogen bond between Met229 and the d-glucose residue of G3 in subsite +2, and this interaction may enhance transglucosylation.
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Affiliation(s)
| | - Wataru Saburi
- Research Faculty of Agriculture, Hokkaido Unifversity, Sapporo 060-8589, Japan; (W.A.)
- Correspondence: (W.S.); (H.M.); Tel.: +81-11-806-2508 (W.S.); +81-11-706-2497 (H.M.)
| | - Tomoya Ota
- Research Faculty of Agriculture, Hokkaido Unifversity, Sapporo 060-8589, Japan; (W.A.)
| | - Jian Yu
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Koji Kato
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Min Yao
- Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Haruhide Mori
- Research Faculty of Agriculture, Hokkaido Unifversity, Sapporo 060-8589, Japan; (W.A.)
- Correspondence: (W.S.); (H.M.); Tel.: +81-11-806-2508 (W.S.); +81-11-706-2497 (H.M.)
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4
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Butterworth PJ, Bajka BH, Edwards CH, Warren FJ, Ellis PR. Enzyme kinetic approach for mechanistic insight and predictions of in vivo starch digestibility and the glycaemic index of foods. Trends Food Sci Technol 2022; 120:254-264. [PMID: 35210697 PMCID: PMC8850932 DOI: 10.1016/j.tifs.2021.11.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/09/2021] [Accepted: 11/14/2021] [Indexed: 12/18/2022]
Abstract
Background Starch is a principal dietary source of digestible carbohydrate and energy. Glycaemic and insulinaemic responses to foods containing starch vary considerably and glucose responses to starchy foods are often described by the glycaemic index (GI) and/or glycaemic load (GL). Low GI/GL foods are beneficial in the management of cardiometabolic disorders (e.g., type 2 diabetes, cardiovascular disease). Differences in rates and extents of digestion of starch-containing foods will affect postprandial glycaemia. Scope and approach Amylolysis kinetics are influenced by structural properties of the food matrix and of starch itself. Native (raw) semi-crystalline starch is digested slowly but hydrothermal processing (cooking) gelatinises the starch and greatly increases its digestibility. In plants, starch granules are contained within cells and intact cell walls can limit accessibility of water and digestive enzymes hindering gelatinisation and digestibility. In vitro studies of starch digestion by α-amylase model early stages in digestion and can suggest likely rates of digestion in vivo and expected glycaemic responses. Reports that metabolic responses to dietary starch are influenced by α-amylase gene copy number, heightens interest in amylolysis. Key findings and conclusions This review shows how enzyme kinetic strategies can provide explanations for differences in digestion rate of different starchy foods. Michaelis-Menten and Log of Slope analyses provide kinetic parameters (e.g., Km and kcat/Km) for evaluating catalytic efficiency and ease of digestibility of starch by α-amylase. Suitable kinetic methods maximise the information that can be obtained from in vitro work for predictions of starch digestion and glycaemic responses in vivo. Michaelis-Menten kinetics determines catalytic efficiency of amylase action on starch. Kinetic parameters Km and kcat/Km are useful for estimating ease of digestibility. Log of slope analysis can quantify starch fractions digested at different rates. Categorisation of Resistant Starch can be based on types of interaction with amylase. Enzyme kinetic studies of amylolysis are useful for predicting postprandial glycaemia.
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Affiliation(s)
- Peter J. Butterworth
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Balázs H. Bajka
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Cathrina H. Edwards
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Frederick J. Warren
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Peter R. Ellis
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
- Corresponding author. Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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5
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Mehmood H, Haroon M, Akhtar T, Woodward S, Andleeb H. Synthesis and molecular docking studies of 5-acetyl-2-(arylidenehydrazin-1-yl)-4-methyl-1,3-thiazoles as α-amylase inhibitors. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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6
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Tsukamoto K, Ariki S, Nakazawa M, Sakamoto T, Ueda M. Novel cold-adapted raw-starch digesting α-amylases from Eisenia fetida: Gene cloning, expression, and characterization. BIOTECHNOLOGY REPORTS 2021; 31:e00662. [PMID: 34557389 PMCID: PMC8446577 DOI: 10.1016/j.btre.2021.e00662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 07/01/2021] [Accepted: 07/28/2021] [Indexed: 11/25/2022]
Abstract
There have been few reports about gene cloning and expression of α-amylases from E. fetida. Ef-Amy I and II were shown to 89% identity of amino acid sequences. The catalytically important residues of α-amylase of GH family 13 were conserved in Ef-amy I and II. The substrate specificities of rEf-Amy I and II were dissimilar. It found that rEf-Amy I and II could be possible use for simultaneous saccharification and fermentation process.
We identified the raw-starch-digesting α-amylase genes a earthworm Eisenia fetid α amylase I and II (Ef-Amy I and Ef-Amy II). Each gene consists of 1,530 base pairs (bp) that encode proteins of 510 amino acids, as indicated by the corresponding mRNA sequences. Ef-Amy I and II showed an 89% amino acid identity. The amino acid sequences of Ef-Amy I and II were similar to those of the α-amylases from porcine pancreas, human pancreas, Tenebrio molitor, Oryctolagus cuniculus, and Xenopus (Silurana) tropicalis. Each gene encoding mature Ef-Amy I and II was expressed in the GS115 strain of Pichia pastoris. The molecular masses of the recombinant Ef-Amy I and II were 57 kDa each, and catalytically important residues of α-amylases of the GH family 13 were conserved in both proteins. These amylases exhibited raw-starch-digesting activity at 4 °C. The substrate specificities of rEf-Amy I and II were dissimilar. rEf-Amy I and II were shown to be active even in 40% ethanol, 4 M NaCl, and 4 M KCl.
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7
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Digestibility of resistant starch type 3 is affected by crystal type, molecular weight and molecular weight distribution. Carbohydr Polym 2021; 265:118069. [PMID: 33966833 DOI: 10.1016/j.carbpol.2021.118069] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 02/06/2023]
Abstract
Resistant starch type 3 (RS-3) holds great potential as a prebiotic by supporting gut microbiota following intestinal digestion. However the factors influencing the digestibility of RS-3 are largely unknown. This research aims to reveal how crystal type and molecular weight (distribution) of RS-3 influence its resistance. Narrow and polydisperse α-glucans of degree of polymerization (DP) 14-76, either obtained by enzymatic synthesis or debranching amylopectins from different sources, were crystallized in 12 different A- or B-type crystals and in vitro digested. Crystal type had the largest influence on resistance to digestion (A >>> B), followed by molecular weight (Mw) (high DP >> low DP) and Mw distribution (narrow disperse > polydisperse). B-type crystals escaping digestion changed in Mw and Mw distribution compared to that in the original B-type crystals, whereas A-type crystals were unchanged. This indicates that pancreatic α-amylase binds and acts differently to A- or B-type RS-3 crystals.
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8
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Dandekar P, Kotmale AS, Chavan SR, Kadlag PP, Sawant SV, Dhavale DD, RaviKumar A. Insights into the Inhibition Mechanism of Human Pancreatic α-Amylase, a Type 2 Diabetes Target, by Dehydrodieugenol B Isolated from Ocimum tenuiflorum. ACS OMEGA 2021; 6:1780-1786. [PMID: 33521419 PMCID: PMC7841778 DOI: 10.1021/acsomega.0c00617] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/24/2020] [Indexed: 06/12/2023]
Abstract
Use of human pancreatic α-amylase (HPA) inhibitors is one of the effective antidiabetic strategies to lower postprandial hyperglycemia via reduction in the dietary starch hydrolysis rate. Many natural products from plants are being studied for their HPA inhibitory activity. The present study describes isolation of dehydrodieugenol B (DDEB) from Ocimum tenuiflorum leaves using sequential solvent extraction, structure determination by one-dimensional (1D) and two-dimensional (2D) NMR analyses, and characterization as an HPA inhibitor using kinetics, binding thermodynamics, and molecular docking. DDEB uncompetitively inhibited HPA with an IC50 value of 29.6 μM for starch and apparent K i ' of 2.49 and Ki of 47.6 μM for starch and maltopentaose as substrates, respectively. The circular dichroism (CD) study indicated structural changes in HPA on inhibitor binding. Isothermal titration calorimetry (ITC) revealed thermodynamically favorable binding (ΔG of -7.79 kcal mol-1) with a dissociation constant (K d) of 1.97 μM and calculated association constant (K a) of 0.507 μM. Molecular docking showed stable HPA-inhibitor binding involving H-bonds and Pi-alkyl, alkyl-alkyl, and van der Waals (vDW) interactions. The computational docking results support the noncompetitive nature of DDEB binding. The present study could be helpful for exploration of the molecule as a potential antidiabetic drug candidate to control postprandial hyperglycemia.
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Affiliation(s)
- Prasad
D. Dandekar
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
| | - Amol S. Kotmale
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
| | - Shrawan R. Chavan
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
| | - Pranita P. Kadlag
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
| | - Sangeeta V. Sawant
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
| | - Dilip D. Dhavale
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
| | - Ameeta RaviKumar
- Institute
of Bioinformatics and Biotechnology, Garware Research Centre, Department
of Chemistry, and Bioinformatics Centre, Savitribai Phule
Pune University (Formerly University of Pune), Pune 411007 Maharashtra, India
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9
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Božić N, Rozeboom HJ, Lončar N, Slavić MŠ, Janssen DB, Vujčić Z. Characterization of the starch surface binding site on Bacillus paralicheniformis α-amylase. Int J Biol Macromol 2020; 165:1529-1539. [PMID: 33058974 DOI: 10.1016/j.ijbiomac.2020.10.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/03/2020] [Accepted: 10/03/2020] [Indexed: 11/16/2022]
Abstract
α-Amylase from Bacillus paralicheniformis (BliAmy), belonging to GH13_5 subfamily of glycoside hydrolases, was proven to be a highly efficient raw starch digesting enzyme. The ability of some α-amylases to hydrolyze raw starch is related to the existence of surface binding sites (SBSs) for polysaccharides that can be distant from the active site. Crystallographic studies performed on BliAmy in the apo form and of enzyme bound with different oligosaccharides and oligosaccharide precursors revealed binding of these ligands to one SBS with two amino acids F257 and Y358 mainly involved in complex formation. The role of this SBS in starch binding and degradation was probed by designing enzyme variants mutated in this region (F257A and Y358A). Kinetic studies with different substrates show that starch binding through the SBS is disrupted in the mutants and that F257 and Y358 contributed cumulatively to binding and hydrolysis. Mutation of both sites (F257A/Y358A) resulted in a 5-fold lower efficacy with raw starch as substrate and at least 5.5-fold weaker binding compared to the wild type BliAmy, suggesting that the ability of BliAmy to hydrolyze raw starch with high efficiency is related to the level of its adsorption onto starch granules.
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Affiliation(s)
- Nataša Božić
- Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia.
| | - Henriëtte J Rozeboom
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747AG Groningen, the Netherlands
| | - Nikola Lončar
- GECCO Biotech, Nijenborgh 4, Groningen 9747AG, the Netherlands
| | - Marinela Šokarda Slavić
- Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia
| | - Dick B Janssen
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747AG Groningen, the Netherlands
| | - Zoran Vujčić
- Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia
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10
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Ogasawara M, Yoshii K, Wada J, Yamamoto Y, Inouye K. Identification of guanine, guanosine, and inosine for α-amylase inhibitors in the extracts of the earthworm Eisenia fetida and characterization of their inhibitory activities against porcine pancreatic α-amylase. Enzyme Microb Technol 2020; 142:109693. [DOI: 10.1016/j.enzmictec.2020.109693] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 10/08/2020] [Accepted: 10/15/2020] [Indexed: 01/21/2023]
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11
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Hirano Y, Tsukamoto K, Ariki S, Naka Y, Ueda M, Tamada T. X-ray crystallographic structural studies of α-amylase I from Eisenia fetida. Acta Crystallogr D Struct Biol 2020; 76:834-844. [DOI: 10.1107/s2059798320010165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/23/2020] [Indexed: 11/11/2022] Open
Abstract
The earthworm Eisenia fetida possesses several cold-active enzymes, including α-amylase, β-glucanase and β-mannanase. E. fetida possesses two isoforms of α-amylase (Ef-Amy I and II) to digest raw starch. Ef-Amy I retains its catalytic activity at temperatures below 10°C. To identify the molecular properties of Ef-Amy I, X-ray crystal structures were determined of the wild type and of the inactive E249Q mutant. Ef-Amy I has structural similarities to mammalian α-amylases, including the porcine pancreatic and human pancreatic α-amylases. Structural comparisons of the overall structures as well as of the Ca2+-binding sites of Ef-Amy I and the mammalian α-amylases indicate that Ef-Amy I has increased structural flexibility and more solvent-exposed acidic residues. These structural features of Ef-Amy I may contribute to its observed catalytic activity at low temperatures, as many cold-adapted enzymes have similar structural properties. The structure of the substrate complex of the inactive mutant of Ef-Amy I shows that a maltohexaose molecule is bound in the active site and a maltotetraose molecule is bound in the cleft between the N- and C-terminal domains. The recognition of substrate molecules by Ef-Amy I exhibits some differences from that observed in structures of human pancreatic α-amylase. This result provides insights into the structural modulation of the recognition of substrates and inhibitors.
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12
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Desseaux V, Stocker P, Brouant P, Ajandouz EH. The Mechanisms of Alpha-Amylase Inhibition by Flavan-3-Ols and the Possible Impacts of Drinking Green Tea on Starch Digestion. J Food Sci 2018; 83:2858-2865. [DOI: 10.1111/1750-3841.14353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/20/2018] [Accepted: 08/24/2018] [Indexed: 02/02/2023]
Affiliation(s)
- Véronique Desseaux
- Authors are with CNRS, Cent Marseille, iSm2, Marseille; Aix Marseille Univ.; Faculté des Sciences et Techniques de Saint Jérôme, Case 342 13397 Marseille France
| | - Pierre Stocker
- Authors are with CNRS, Cent Marseille, iSm2, Marseille; Aix Marseille Univ.; Faculté des Sciences et Techniques de Saint Jérôme, Case 342 13397 Marseille France
| | - Pierre Brouant
- Authors are with CNRS, Cent Marseille, iSm2, Marseille; Aix Marseille Univ.; Faculté des Sciences et Techniques de Saint Jérôme, Case 342 13397 Marseille France
| | - El Hassan Ajandouz
- Authors are with CNRS, Cent Marseille, iSm2, Marseille; Aix Marseille Univ.; Faculté des Sciences et Techniques de Saint Jérôme, Case 342 13397 Marseille France
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13
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Tysoe C, Withers SG. Structural Dissection of Helianthamide Reveals the Basis of Its Potent Inhibition of Human Pancreatic α-Amylase. Biochemistry 2018; 57:5384-5387. [DOI: 10.1021/acs.biochem.8b00825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christina Tysoe
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- Michael Smith Laboratories, 2125 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Stephen G. Withers
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- Michael Smith Laboratories, 2125 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
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14
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Sun M, Sun Y, Li Y, Liu Y, Liang J, Zhang Z. Physical properties and antidiabetic potential of a novel galactomannan from seeds of Gleditsia japonica var. delavayi. J Funct Foods 2018. [DOI: 10.1016/j.jff.2018.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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15
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Purification of an alpha amylase from Aspergillus flavus NSH9 and molecular characterization of its nucleotide gene sequence. 3 Biotech 2018; 8:204. [PMID: 29607285 DOI: 10.1007/s13205-018-1225-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/22/2018] [Indexed: 10/17/2022] Open
Abstract
In this study, an alpha-amylase enzyme from a locally isolated Aspergillus flavus NSH9 was purified and characterized. The extracellular α-amylase was purified by ammonium sulfate precipitation and anion-exchange chromatography at a final yield of 2.55-fold and recovery of 11.73%. The molecular mass of the purified α-amylase was estimated to be 54 kDa using SDS-PAGE and the enzyme exhibited optimal catalytic activity at pH 5.0 and temperature of 50 °C. The enzyme was also thermally stable at 50 °C, with 87% residual activity after 60 min. As a metalloenzymes containing calcium, the purified α-amylase showed significantly increased enzyme activity in the presence of Ca2+ ions. Further gene isolation and characterization shows that the α-amylase gene of A. flavus NSH9 contained eight introns and an open reading frame that encodes for 499 amino acids with the first 21 amino acids presumed to be a signal peptide. Analysis of the deduced peptide sequence showed the presence of three conserved catalytic residues of α-amylase, two Ca2+-binding sites, seven conserved peptide sequences, and several other properties that indicates the protein belongs to glycosyl hydrolase family 13 capable of acting on α-1,4-bonds only. Based on sequence similarity, the deduced peptide sequence of A. flavus NSH9 α-amylase was also found to carry two potential surface/secondary-binding site (SBS) residues (Trp 237 and Tyr 409) that might be playing crucial roles in both the enzyme activity and also the binding of starch granules.
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Takahama U, Hirota S. Interactions of flavonoids with α-amylase and starch slowing down its digestion. Food Funct 2018; 9:677-687. [DOI: 10.1039/c7fo01539a] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hydrophobic flavonoids can suppress starch digestion in the intestine by forming starch-flavonoid complexes.
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Affiliation(s)
- Umeo Takahama
- Department of Health and Nutritional Care
- Faculty of Allied Health Sciences
- University of East Asia
- Shimonoseki
- Japan
| | - Sachiko Hirota
- Department of Health and Nutritional Care
- Faculty of Allied Health Sciences
- University of East Asia
- Shimonoseki
- Japan
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Božić N, Lončar N, Slavić MŠ, Vujčić Z. Raw starch degrading α-amylases: an unsolved riddle. ACTA ACUST UNITED AC 2017. [DOI: 10.1515/amylase-2017-0002] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractStarch is an important food ingredient and a substrate for the production of many industrial products. Biological and industrial processes involve hydrolysis of raw starch, such as digestion by humans and animals, starch metabolism in plants, and industrial starch conversion for obtaining glucose, fructose and maltose syrup or bioethanol. Raw starch degrading α-amylases (RSDA) can directly degrade raw starch below the gelatinization temperature of starch. Knowledge of the structures and properties of starch and RSDA has increased significantly in recent years. Understanding the relationships between structural peculiarities and properties of RSDA is a prerequisite for efficient application in different aspects of human benefit from health to the industry. This review summarizes recent advances on RSDA research with emphasizes on representatives of glycoside hydrolase family GH13. Definite understanding of raw starch digesting ability is yet to come with accumulating structural and functional studies of RSDA.
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