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Li X, Jin Z, Bai Y, Svensson B. Progress in cyclodextrins as important molecules regulating catalytic processes of glycoside hydrolases. Biotechnol Adv 2024; 72:108326. [PMID: 38382582 DOI: 10.1016/j.biotechadv.2024.108326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/14/2024] [Accepted: 02/18/2024] [Indexed: 02/23/2024]
Abstract
Cyclodextrins (CDs) are important starch derivatives and commonly comprise α-, β-, and γ-CDs. Their hydrophilic surface and hydrophobic inner cavity enable regulation of enzyme catalysis through direct or indirect interactions. Clarifying interactions between CDs and enzyme is of great value for enzyme screening, mechanism exploration, regulation of catalysis, and applications. We summarize the interactions between CDs and glycoside hydrolases (GHs) according to two aspects: 1) CD as products, substrates, inhibitors and activators of enzymes, directly affecting the reaction process; 2) CDs indirectly affecting the enzymatic reaction by solubilizing substrates, relieving substrate/product inhibition, increasing recombinant enzyme production and storage stability, isolating and purifying enzymes, and serving as ligands in crystal structure to identify functional amino acid residues. Additionally, CD enzyme mimetics are developed and used as catalysts in traditional artificial enzymes as well as nanozymes, making the application of CDs no longer limited to GHs. This review concerns the regulation of GHs catalysis by CDs, and gives insights into research on interactions between enzymes and ligands.
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Affiliation(s)
- Xiaoxiao Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zhengyu Jin
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yuxiang Bai
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China.
| | - Birte Svensson
- Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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2
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Aranda-Caraballo J, Saenz RA, López-Zavala AA, Velazquez-Cruz B, Espinosa-Barrera L, Cárdenas-Conejo Y, Zárate-Romero A, Linares-Vergara O, Osuna-Castro JA, Bonales-Alatorre E, Centeno-Leija S, Serrano-Posada H. Binding Specificity of a Novel Cyclo/Maltodextrin-Binding Protein and Its Role in the Cyclodextrin ABC Importer System from Thermoanaerobacterales. Molecules 2023; 28:6080. [PMID: 37630332 PMCID: PMC10458862 DOI: 10.3390/molecules28166080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
Extracellular synthesis of functional cyclodextrins (CDs) as intermediates of starch assimilation is a convenient microbial adaptation to sequester substrates, increase the half-life of the carbon source, carry bioactive compounds, and alleviate chemical toxicity through the formation of CD-guest complexes. Bacteria encoding the four steps of the carbohydrate metabolism pathway via cyclodextrins (CM-CD) actively internalize CDs across the microbial membrane via a putative type I ATP-dependent ABC sugar importer system, MdxEFG-(X/MsmX). While the first step of the CM-CD pathway encompasses extracellular starch-active cyclomaltodextrin glucanotransferases (CGTases) to synthesize linear dextrins and CDs, it is the ABC importer system in the second step that is the critical factor in determining which molecules from the CGTase activity will be internalized by the cell. Here, structure-function relationship studies of the cyclo⁄maltodextrin-binding protein MdxE of the MdxEFG-MsmX importer system from Thermoanaerobacter mathranii subsp. mathranii A3 are presented. Calorimetric and fluorescence studies of recombinant MdxE using linear dextrins and CDs showed that although MdxE binds linear dextrins and CDs with high affinity, the open-to-closed conformational change is solely observed after α- and β-CD binding, suggesting that the CM-CD pathway from Thermoanaerobacterales is exclusive for cellular internalization of these molecules. Structural analysis of MdxE coupled with docking simulations showed an overall architecture typically found in sugar-binding proteins (SBPs) that comprised two N- and C-domains linked by three small hinge regions, including the conserved aromatic triad Tyr193/Trp269/Trp378 in the C-domain and Phe87 in the N-domain involved in CD recognition and stabilization. Structural bioinformatic analysis of the entire MdxFG-MsmX importer system provided further insights into the binding, internalization, and delivery mechanisms of CDs. Hence, while the MdxE-CD complex couples to the permease subunits MdxFG to deliver the CD into the transmembrane channel, the dimerization of the cytoplasmatic promiscuous ATPase MsmX triggers active transport into the cytoplasm. This research provides the first results on a novel thermofunctional SBP and its role in the internalization of CDs in extremely thermophilic bacteria.
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Affiliation(s)
- Jorge Aranda-Caraballo
- Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico; (J.A.-C.); (B.V.-C.); (L.E.-B.); (O.L.-V.)
| | - Roberto A. Saenz
- Facultad de Ciencias, Universidad de Colima, Bernal Díaz del Castillo 340, Colima 28045, Mexico;
| | - Alonso A. López-Zavala
- Departamento de Ciencias Químico-Biológicas, Universidad de Sonora, Hermosillo 83000, Mexico;
| | - Beatriz Velazquez-Cruz
- Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico; (J.A.-C.); (B.V.-C.); (L.E.-B.); (O.L.-V.)
| | - Laura Espinosa-Barrera
- Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico; (J.A.-C.); (B.V.-C.); (L.E.-B.); (O.L.-V.)
| | - Yair Cárdenas-Conejo
- Consejo Nacional de Humanidades, Ciencias y Tecnologías, Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico;
| | - Andrés Zárate-Romero
- Consejo Nacional de Humanidades, Ciencias y Tecnologías, Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Km 107 CarreteraTijuana-Ensenada, Ensenada 22860, Mexico;
| | - Oscar Linares-Vergara
- Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico; (J.A.-C.); (B.V.-C.); (L.E.-B.); (O.L.-V.)
| | - Juan A. Osuna-Castro
- Facultad de Ciencias Biológicas y Agropecuarias, Universidad de Colima, Autopista Colima-Manzanillo, Tecomán 28100, Mexico;
| | - Edgar Bonales-Alatorre
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Avenida 25 de julio 965, Colonia Villa de San Sebastián, Colima 28045, Mexico;
| | - Sara Centeno-Leija
- Consejo Nacional de Humanidades, Ciencias y Tecnologías, Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico;
| | - Hugo Serrano-Posada
- Consejo Nacional de Humanidades, Ciencias y Tecnologías, Laboratorio de Biología Sintética, Estructural y Molecular, Universidad de Colima, Carretera Los Limones-Loma de Juárez, Colima 28627, Mexico;
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3
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Kovacs T, Nagy P, Panyi G, Szente L, Varga Z, Zakany F. Cyclodextrins: Only Pharmaceutical Excipients or Full-Fledged Drug Candidates? Pharmaceutics 2022; 14:pharmaceutics14122559. [PMID: 36559052 PMCID: PMC9788615 DOI: 10.3390/pharmaceutics14122559] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
Cyclodextrins, representing a versatile family of cyclic oligosaccharides, have extensive pharmaceutical applications due to their unique truncated cone-shaped structure with a hydrophilic outer surface and a hydrophobic cavity, which enables them to form non-covalent host-guest inclusion complexes in pharmaceutical formulations to enhance the solubility, stability and bioavailability of numerous drug molecules. As a result, cyclodextrins are mostly considered as inert carriers during their medical application, while their ability to interact not only with small molecules but also with lipids and proteins is largely neglected. By forming inclusion complexes with cholesterol, cyclodextrins deplete cholesterol from cellular membranes and thereby influence protein function indirectly through alterations in biophysical properties and lateral heterogeneity of bilayers. In this review, we summarize the general chemical principles of direct cyclodextrin-protein interactions and highlight, through relevant examples, how these interactions can modify protein functions in vivo, which, despite their huge potential, have been completely unexploited in therapy so far. Finally, we give a brief overview of disorders such as Niemann-Pick type C disease, atherosclerosis, Alzheimer's and Parkinson's disease, in which cyclodextrins already have or could have the potential to be active therapeutic agents due to their cholesterol-complexing or direct protein-targeting properties.
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Affiliation(s)
- Tamas Kovacs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Peter Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Lajos Szente
- CycloLab Cyclodextrin R & D Laboratory Ltd., H-1097 Budapest, Hungary
| | - Zoltan Varga
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Florina Zakany
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
- Correspondence:
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Kaymaz B, Mustafa W, Hall S, Vlaisavljevich E, Sensoy O, Yuksel Durmaz Y. Experimental and Computational Investigation of Clustering Behavior of Cyclodextrin-Perfluorocarbon Inclusion Complexes as Effective Histotripsy Agents. Mol Pharm 2022; 19:2907-2921. [PMID: 35839291 DOI: 10.1021/acs.molpharmaceut.2c00268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently developed nanocones (NCs), which are inclusion complexes that are made up of cyclodextrins (CDs) and perfluorocarbons (PFCs), have shown promising results in nanoparticle-mediated histotripsy (NMH) applications due to stable inclusion complexation, PFC quantification, simple synthesis, and processing. FDA-approved βCD and its modified versions such as low-degree methylated βCD have been previously demonstrated as prime examples of structures capable of accommodating PFC molecules. However, the complex formation potential of different CDs with various cavity sizes in the presence of PFC molecules, and their consequent aggregation, needs to be explored. In the present study, the complexation and aggregation potential of some natural CDs and their respective derivatives either exposed to perfluoropentane (PFP) or perfluorohexane (PFH) were studied in the wet lab. Computational studies were also performed to account for the limitations faced in PFC quantification because of the low optical density of PFCs within the CD complex and to discover the best candidate for NMH applications. All results revealed that only βCD and γCD (except HMγCD) derivatives form an inclusion complex with PFCs and only LMβCD, βCD, and γCD form nanocone clusters (NCCs), which precipitate and can be collected for use. Furthermore, the data collectively show that βCD and PFCs have the best complexation due to stable complex formation, ease of production, and product recovery, especially with PFH as a more suitable candidate due to its high boiling point, which allows workability during synthesis. Although simulations suggest that highly stable inclusion complexes exist, such as HPβCD, the cluster formation resulting in precipitation is hindered due to the high solubility of CDs in water, resulting in intangible yields to work with even after employing general laboratory recovery methods. Conclusively, histotripsy cavitation experiments successfully showed a decreased cavitation threshold among optimal NCC candidates that were identified, supporting their use in NMH.
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Affiliation(s)
- Betül Kaymaz
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Waleed Mustafa
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Sarah Hall
- Department of Biomedical Engineering and Mechanics, Virginia Tech 24061, United States
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Tech 24061, United States
| | - Ozge Sensoy
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey.,Research Institute of Health Science and Technologies (SABITA), Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Yasemin Yuksel Durmaz
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey.,Research Institute of Health Science and Technologies (SABITA), Istanbul Medipol University, 34810 Istanbul, Turkey
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5
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Kohno M, Arakawa T, Sunagawa N, Mori T, Igarashi K, Nishimoto T, Fushinobu S. Molecular analysis of cyclic α-maltosyl-(1→6)-maltose binding protein in the bacterial metabolic pathway. PLoS One 2020; 15:e0241912. [PMID: 33211750 PMCID: PMC7676653 DOI: 10.1371/journal.pone.0241912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/22/2020] [Indexed: 11/18/2022] Open
Abstract
Cyclic α-maltosyl-(1→6)-maltose (CMM) is a cyclic glucotetrasaccharide with alternating α-1,4 and α-1,6 linkages. Here, we report functional and structural analyses on CMM-binding protein (CMMBP), which is a substrate-binding protein (SBP) of an ABC importer system of the bacteria Arthrobacter globiformis. Isothermal titration calorimetry analysis revealed that CMMBP specifically bound to CMM with a Kd value of 9.6 nM. The crystal structure of CMMBP was determined at a resolution of 1.47 Å, and a panose molecule was bound in a cleft between two domains. To delineate its structural features, the crystal structure of CMMBP was compared with other SBPs specific for carbohydrates, such as cyclic α-nigerosyl-(1→6)-nigerose and cyclodextrins. These results indicate that A. globiformis has a unique metabolic pathway specialized for CMM.
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Affiliation(s)
- Masaki Kohno
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
- R&D Division, HAYASHIBARA CO., LTD., Okayama, Japan
| | - Takatoshi Arakawa
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Naoki Sunagawa
- Department of Biomaterial Sciences, The University of Tokyo, Tokyo, Japan
| | - Tetsuya Mori
- R&D Division, HAYASHIBARA CO., LTD., Okayama, Japan
| | - Kiyohiko Igarashi
- Department of Biomaterial Sciences, The University of Tokyo, Tokyo, Japan
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
| | | | - Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
- * E-mail:
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Chandravanshi M, Sharma A, Dasgupta P, Mandal SK, Kanaujia SP. Identification and characterization of ABC transporters for carbohydrate uptake in Thermus thermophilus HB8. Gene 2019; 696:135-148. [DOI: 10.1016/j.gene.2019.02.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/01/2019] [Indexed: 02/06/2023]
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7
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Fukamizo T, Kitaoku Y, Suginta W. Periplasmic solute-binding proteins: Structure classification and chitooligosaccharide recognition. Int J Biol Macromol 2019; 128:985-993. [PMID: 30771387 DOI: 10.1016/j.ijbiomac.2019.02.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 01/12/2019] [Accepted: 02/11/2019] [Indexed: 12/17/2022]
Abstract
Periplasmic solute-binding proteins (SBPs) serve as molecular shuttles that assist the transport of small solutes from the outer membrane to the inner membrane of all Gram-negative bacteria. Based on the available crystal structures, SBPs are classified into seven clusters, A-G, and are further divided into subclusters, IV. This minireview is focused on the classification, structure and substrate specificity of a distinct class of SBPs specific for chitooligosaccharides (CBPs). To date, only two structures of CBP homologues, VhCBP and VcCBP, have been reported in the marine Vibrio species, with exposition of their limited function. The Vibrio CBPs are structurally classified as cluster C/subcluster IV SBPs that exclusively recognize β-1,4- or β-1,3-linked linear oligosaccharides. The overall structural feature of the Vibrios CBPs is most similar to the cellobiose-binding orthologue from the hyperthermophilic bacterium Thermotoga maritima. This similarity provides an opportunity to engineer the substrate specificity of the proteins and to control the uptake of chitinous and cellulosic nutrients in marine bacteria.
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Affiliation(s)
- Tamo Fukamizo
- Biochemistry and Electrochemistry Research Unit and School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Yoshihito Kitaoku
- Biochemistry and Electrochemistry Research Unit and School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Wipa Suginta
- Biochemistry and Electrochemistry Research Unit and School of Chemistry, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Payupnai, Wangchan, Rayong 21210, Thailand.
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Licht A, Bommer M, Werther T, Neumann K, Hobe C, Schneider E. Structural and functional characterization of a maltose/maltodextrin ABC transporter comprising a single solute binding domain (MalE) fused to the transmembrane subunit MalF. Res Microbiol 2019; 170:1-12. [DOI: 10.1016/j.resmic.2018.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/15/2018] [Accepted: 08/28/2018] [Indexed: 01/21/2023]
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Gebhardt J, Kleist C, Jakobtorweihen S, Hansen N. Validation and Comparison of Force Fields for Native Cyclodextrins in Aqueous Solution. J Phys Chem B 2018; 122:1608-1626. [PMID: 29287148 DOI: 10.1021/acs.jpcb.7b11808] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Molecular dynamics simulations of native α-, β-, and γ-cyclodextrin in aqueous solution have been conducted with the goal to investigate the performance of the CHARMM36 force field, the AMBER-compatible q4md-CD force field, and five variants of the GROMOS force field. The properties analyzed are structural parameters derived from X-ray diffraction and NMR experiments as well as hydrogen bonds and hydration patterns, including hydration free enthalpies. Recent revisions of the torsional-angle parameters for carbohydrate systems within the GROMOS family of force fields lead to a significant improvement of the agreement between simulated and experimental NMR data. Therefore, we recommend using the variant 53A6GLYC instead of 53A6 and 56A6CARBO_R or 2016H66 instead of 56A6CARBO to simulate cyclodextrins in solution. The CHARMM36 and q4md-CD force fields show a similar performance as the three recommended GROMOS parameter sets. A significant difference is the more flexible nature of the cyclodextrins modeled with the CHARMM36 and q4md-CD force fields compared to the three recommended GROMOS parameter sets.
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Affiliation(s)
- Julia Gebhardt
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart , D-70569 Stuttgart, Germany
| | - Catharina Kleist
- Institute of Thermal Separation Processes, Hamburg University of Technology , D-21073 Hamburg, Germany
| | - Sven Jakobtorweihen
- Institute of Thermal Separation Processes, Hamburg University of Technology , D-21073 Hamburg, Germany
| | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart , D-70569 Stuttgart, Germany
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Homburg C, Bommer M, Wuttge S, Hobe C, Beck S, Dobbek H, Deutscher J, Licht A, Schneider E. Inducer exclusion in Firmicutes: insights into the regulation of a carbohydrate ATP binding cassette transporter from Lactobacillus casei BL23 by the signal transducing protein P-Ser46-HPr. Mol Microbiol 2017; 105:25-45. [PMID: 28370477 DOI: 10.1111/mmi.13680] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2017] [Indexed: 12/24/2022]
Abstract
Catabolite repression is a mechanism that enables bacteria to control carbon utilization. As part of this global regulatory network, components of the phosphoenolpyruvate:carbohydrate phosphotransferase system inhibit the uptake of less favorable sugars when a preferred carbon source such as glucose is available. This process is termed inducer exclusion. In bacteria belonging to the phylum Firmicutes, HPr, phosphorylated at serine 46 (P-Ser46-HPr) is the key player but its mode of action is elusive. To address this question at the level of purified protein components, we have chosen a homolog of the Escherichia coli maltose/maltodextrin ATP-binding cassette transporter from Lactobacillus casei (MalE1-MalF1G1K12 ) as a model system. We show that the solute binding protein, MalE1, binds linear and cyclic maltodextrins but not maltose. Crystal structures of MalE1 complexed with these sugars provide a clue why maltose is not a substrate. P-Ser46-HPr inhibited MalE1/maltotetraose-stimulated ATPase activity of the transporter incorporated in proteoliposomes. Furthermore, cross-linking experiments revealed that P-Ser46-HPr contacts the nucleotide-binding subunit, MalK1, in proximity to the Walker A motif. However, P-Ser46-HPr did not block binding of ATP to MalK1. Together, our findings provide first biochemical evidence that P-Ser-HPr arrests the transport cycle by preventing ATP hydrolysis at the MalK1 subunits of the transporter.
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Affiliation(s)
- Constanze Homburg
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Martin Bommer
- Institut für Biologie/Strukturbiologie und Biochemie, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Steven Wuttge
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Carolin Hobe
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Sebastian Beck
- Institut für Chemie/Angewandte Analytik und Umweltchemie, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Holger Dobbek
- Institut für Biologie/Strukturbiologie und Biochemie, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, F-78350, France.,Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, UMR8261, Paris, F-75005, France
| | - Anke Licht
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Erwin Schneider
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
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Pandey S, Modak A, Phale PS, Bhaumik P. High Resolution Structures of Periplasmic Glucose-binding Protein of Pseudomonas putida CSV86 Reveal Structural Basis of Its Substrate Specificity. J Biol Chem 2016; 291:7844-57. [PMID: 26861882 DOI: 10.1074/jbc.m115.697268] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 01/31/2023] Open
Abstract
Periplasmic substrate-binding proteins (SBPs) bind to the specific ligand with high affinity and mediate their transport into the cytoplasm via the cognate inner membrane ATP-binding cassette proteins. Because of low sequence identities, understanding the structural basis of substrate recognition by SBPs has remained very challenging. There are several structures available for the ligand-bound sugar SBPs, but very few unliganded structures are reported. No structural data are available for sugar SBPs fromPseudomonassp. to date. This study reports the first high resolution crystal structures of periplasmic glucose-binding protein fromPseudomonas putidaCSV86 (ppGBP) in unliganded form (2.5 Å) and complexed with glucose (1.25 Å) and galactose (1.8 Å). Asymmetric domain closure of ppGBP was observed upon substrate binding. The ppGBP was found to have an affinity of ∼ 0.3 μmfor glucose. The structural analysis showed that the sugars are bound to the protein mainly by hydrogen bonds, and the loss of two strong hydrogen bonds between ppGBP and galactose compared with glucose may be responsible for lowering its affinity toward galactose. The higher stability of ppGBP-glucose complex was also indicated by an 8 °C increase in the melting temperature compared with unliganded form and ppGBP-galactose complex. ppGBP binds to monosaccharide, but the structural features revealed it to have an oligosaccharide-binding protein fold, indicating that during evolution the sugar binding pocket may have undergone structural modulation to accommodate monosaccharide only.
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Affiliation(s)
- Suman Pandey
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Arnab Modak
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prashant S Phale
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Prasenjit Bhaumik
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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12
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Gannimani R, Ramesh M, Mtambo S, Pillay K, Soliman ME, Govender P. γ-Cyclodextrin capped silver nanoparticles for molecular recognition and enhancement of antibacterial activity of chloramphenicol. J Inorg Biochem 2016; 157:15-24. [PMID: 26824520 DOI: 10.1016/j.jinorgbio.2016.01.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/27/2015] [Accepted: 01/07/2016] [Indexed: 01/14/2023]
Abstract
Computational studies were conducted to identify the favourable formation of the inclusion complex of chloramphenicol with cyclodextrins. The results of molecular docking and molecular dynamics predicted the strongest interaction of chloramphenicol with γ-cyclodextrin. Further, the inclusion complex of chloramphenicol with γ-cyclodextrin was experimentally prepared and a phenomenon of inclusion was verified by using different characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, (1)H nuclear magnetic resonance (NMR) and two dimensional nuclear overhauser effect spectroscopy (NOESY) experiments. From these results it was concluded that γ-cyclodextrins could be an appropriate cyclodextrin polymer which can be used to functionalize chloramphenicol on the surface of silver nanoparticles. In addition, γ-cyclodextrin capped silver nanoparticles were synthesized and characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. Molecular recognition of chloramphenicol by these cyclodextrin capped silver nanoparticles was confirmed by surface enhanced raman spectroscopy (SERS) experiments. Synergistic antibacterial effect of chloramphenicol with γ-cyclodextrin capped silver nanoparticles was evaluated against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 5129), Klebsiella pneumoniae (ATCC 700603) and Staphylococcus aureus (ATCC 43300). The results from the antibacterial experiment were favourable thus allowing us to conclude that the approach of modifying organic drug molecules with cyclodextrin capped inorganic silver nanoparticles could help to enhance the antibacterial activity of them.
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Affiliation(s)
- Ramesh Gannimani
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa
| | - Muthusamy Ramesh
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa
| | - Sphamandla Mtambo
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa
| | - Karen Pillay
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa
| | - Mahmoud E Soliman
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa
| | - Patrick Govender
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban 4000, South Africa.
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13
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Ikryannikova LN, Ischenko DS, Lominadze GG, Kanygina AV, Karpova IY, Kostryukova ES, Mayansky NA, Skvortsov VS, Ilina EN, Govorun VM. The mystery of the fourth clone: comparative genomic analysis of four non-typeable Streptococcus pneumoniae strains with different susceptibilities to optochin. Eur J Clin Microbiol Infect Dis 2015; 35:119-30. [PMID: 26563895 DOI: 10.1007/s10096-015-2516-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/26/2015] [Indexed: 11/25/2022]
Abstract
Optochin-resistant pneumococci can be rarely caught in clinical microbiology laboratories because of the routine identification of all such strains as viridans group non-pneumococci. We were lucky to find four non-typeable Streptococcus pneumoniae clones demonstrating the different susceptibilities to optochin: one of them (Spn_13856) was resistant to optochin, while the other three (Spn_1719, Spn_27, and Spn_2298) were susceptible. Whole genome nucleotide sequences of these strains were compared to reveal the differences between the optochin-resistant and optochin-susceptible strains. Two adjacent genes coding maltose O-acetyltransferase and uridine phosphorylase which were presented in the genomes of all optochin-susceptible strains and missed in the optochin-resistant strain were revealed. Non-synonymous substitutions in 14 protein-coding genes were discovered, including the Ala49Ser mutation in the C-subunit of the F0 part of the ATP synthase rotor usually associated with pneumococcal optochin resistance. Modeling of a process of optochin interaction with the F0 part of the ATP synthase rotor indicates that the complex of optochin with "domain C" composed by wild-type C-subunits is more stable than the same complex composed of Ala49Ser mutant C-subunits.
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Affiliation(s)
- L N Ikryannikova
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia.
| | - D S Ischenko
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia
| | - G G Lominadze
- Federal State Budgetary Institute "Scientific Center of Children Health" of RAMS, Moscow, Russia
| | - A V Kanygina
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia
| | - I Y Karpova
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia
| | - E S Kostryukova
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia
| | - N A Mayansky
- Federal State Budgetary Institute "Scientific Center of Children Health" of RAMS, Moscow, Russia
| | - V S Skvortsov
- Institute of Biomedical Chemistry, 10 Pogodinskaya str., Moscow, 119121, Russia
| | - E N Ilina
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia
| | - V M Govorun
- Research Institute of Physical-Chemical Medicine, Ministry of Public Health of Russian Federation, 119992, Malaya Pirogovskaya str., 1a, Moscow, Russia
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14
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Gannimani R, Perumal A, Ramesh M, Pillay K, Soliman ME, Govender P. Antipyrine–gamma cyclodextrin inclusion complex: Molecular modeling, preparation, characterization and cytotoxicity studies. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.02.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Cockburn DW, Orlovsky NI, Foley MH, Kwiatkowski KJ, Bahr CM, Maynard M, Demeler B, Koropatkin NM. Molecular details of a starch utilization pathway in the human gut symbiont Eubacterium rectale. Mol Microbiol 2015; 95:209-30. [PMID: 25388295 PMCID: PMC4437465 DOI: 10.1111/mmi.12859] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2014] [Indexed: 01/07/2023]
Abstract
Eubacterium rectale is a prominent human gut symbiont yet little is known about the molecular strategies this bacterium has developed to acquire nutrients within the competitive gut ecosystem. Starch is one of the most abundant glycans in the human diet, and E. rectale increases in vivo when the host consumes a diet rich in resistant starch, although it is not a primary degrader of this glycan. Here we present the results of a quantitative proteomics study in which we identify two glycoside hydrolase 13 family enzymes, and three ABC transporter solute-binding proteins that are abundant during growth on starch and, we hypothesize, work together at the cell surface to degrade starch and capture the released maltooligosaccharides. EUR_21100 is a multidomain cell wall anchored amylase that preferentially targets starch polysaccharides, liberating maltotetraose, whereas the membrane-associated maltogenic amylase EUR_01860 breaks down maltooligosaccharides longer than maltotriose. The three solute-binding proteins display a range of glycan-binding specificities that ensure the capture of glucose through maltoheptaose and some α1,6-branched glycans. Taken together, we describe a pathway for starch utilization by E. rectale DSM 17629 that may be conserved among other starch-degrading Clostridium cluster XIVa organisms in the human gut.
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Affiliation(s)
- Darrell W. Cockburn
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Nicole I. Orlovsky
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Matthew H. Foley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Kurt J. Kwiatkowski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Constance M. Bahr
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Mallory Maynard
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Borries Demeler
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, TX 78229
| | - Nicole M. Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
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16
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GHOSH SAPTARSHI, PAUL BIJANKUMAR, CHATTOPADHYAY NITIN. Interaction of cyclodextrins with human and bovine serum albumins: A combined spectroscopic and computational investigation. J CHEM SCI 2014. [DOI: 10.1007/s12039-014-0652-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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Medrano FJ, de Souza CS, Romero A, Balan A. Structure determination of a sugar-binding protein from the phytopathogenic bacterium Xanthomonas citri. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:564-71. [PMID: 24817711 DOI: 10.1107/s2053230x14006578] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 03/25/2014] [Indexed: 02/05/2023]
Abstract
The uptake of maltose and related sugars in Gram-negative bacteria is mediated by an ABC transporter encompassing a periplasmic component (the maltose-binding protein or MalE), a pore-forming membrane protein (MalF and MalG) and a membrane-associated ATPase (MalK). In the present study, the structure determination of the apo form of the putative maltose/trehalose-binding protein (Xac-MalE) from the citrus pathogen Xanthomonas citri in space group P6522 is described. The crystals contained two protein molecules in the asymmetric unit and diffracted to 2.8 Å resolution. Xac-MalE conserves the structural and functional features of sugar-binding proteins and a ligand-binding pocket with similar characteristics to eight different orthologues, including the residues for maltose and trehalose interaction. This is the first structure of a sugar-binding protein from a phytopathogenic bacterium, which is highly conserved in all species from the Xanthomonas genus.
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Affiliation(s)
- Francisco Javier Medrano
- Department of Chemical and Physical Biology, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
| | - Cristiane Santos de Souza
- Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, Cidade Universitária, SP, Brazil
| | - Antonio Romero
- Department of Chemical and Physical Biology, Centro de Investigaciones Biologicas (CSIC), Madrid, Spain
| | - Andrea Balan
- Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, Cidade Universitária, SP, Brazil
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18
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Fernandes A, Ivanova G, Brás NF, Mateus N, Ramos MJ, Rangel M, de Freitas V. Structural characterization of inclusion complexes between cyanidin-3-O-glucoside and β-cyclodextrin. Carbohydr Polym 2013; 102:269-77. [PMID: 24507282 DOI: 10.1016/j.carbpol.2013.11.037] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 11/06/2013] [Accepted: 11/26/2013] [Indexed: 11/25/2022]
Abstract
Inclusion complex formation between the multiple equilibrium forms of cyanidin-3-O-glucoside (cy3glc) and β-cyclodextrin (β-CD) was investigated using a combined approach of NMR spectroscopy and Molecular Dynamics simulation. Diffusion ordered NMR spectroscopy (DOSY) and study of nuclear Overhauser effects (NOE) were used to determine the selective intermolecular interactions and structure of these complexes in aqueous solution. The observed chemical shift displacements of resonance signals of protons from the interior of β-CD cavity and protons belonging to the hemiketal (B) and cis-chalcone forms (Cc), the diffusion measurements using DOSY and the NOE studies have anticipated the formation of an inclusion complex between these two forms and β-CD. The analysis of the NMR spectral data has shown no evidence of internal interaction between β-CD and the flavylium cation (AH(+)) or trans-chalcone (Ct) forms of cy3glc. The hemiketal formed a 1:1 inclusion complex with β-cyclodextrin in which the pyranic C ring is deeply included inside the β-CD cavity while B ring lies on the plane of the wider rim of β-CD. The structure of the complexes was also clarified through a theoretical approach by Molecular Dynamics simulation.
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Affiliation(s)
- Ana Fernandes
- Centro de Investigação em Química (CIQ), Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Galya Ivanova
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Natércia F Brás
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Nuno Mateus
- Centro de Investigação em Química (CIQ), Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
| | - Maria J Ramos
- REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Maria Rangel
- REQUIMTE, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Victor de Freitas
- Centro de Investigação em Química (CIQ), Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
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20
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Evidence for an allosteric mechanism of substrate release from membrane-transporter accessory binding proteins. Proc Natl Acad Sci U S A 2011; 108:E1285-92. [PMID: 22084072 DOI: 10.1073/pnas.1112534108] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Numerous membrane importers rely on accessory water-soluble proteins to capture their substrates. These substrate-binding proteins (SBP) have a strong affinity for their ligands; yet, substrate release onto the low-affinity membrane transporter must occur for uptake to proceed. It is generally accepted that release is facilitated by the association of SBP and transporter, upon which the SBP adopts a conformation similar to the unliganded state, whose affinity is sufficiently reduced. Despite the appeal of this mechanism, however, direct supporting evidence is lacking. Here, we use experimental and theoretical methods to demonstrate that an allosteric mechanism of enhanced substrate release is indeed plausible. First, we report the atomic-resolution structure of apo TeaA, the SBP of the Na(+)-coupled ectoine TRAP transporter TeaBC from Halomonas elongata DSM2581(T), and compare it with the substrate-bound structure previously reported. Conformational free-energy landscape calculations based upon molecular dynamics simulations are then used to dissect the mechanism that couples ectoine binding to structural change in TeaA. These insights allow us to design a triple mutation that biases TeaA toward apo-like conformations without directly perturbing the binding cleft, thus mimicking the influence of the membrane transporter. Calorimetric measurements demonstrate that the ectoine affinity of the conformationally biased triple mutant is 100-fold weaker than that of the wild type. By contrast, a control mutant predicted to be conformationally unbiased displays wild-type affinity. This work thus demonstrates that substrate release from SBPs onto their membrane transporters can be facilitated by the latter through a mechanism of allosteric modulation of the former.
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Eitinger T, Rodionov DA, Grote M, Schneider E. Canonical and ECF-type ATP-binding cassette importers in prokaryotes: diversity in modular organization and cellular functions. FEMS Microbiol Rev 2011; 35:3-67. [PMID: 20497229 DOI: 10.1111/j.1574-6976.2010.00230.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Thomas Eitinger
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, Germany
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Crystal Structure of an Essential Enzyme in Seed Starch Degradation: Barley Limit Dextrinase in Complex with Cyclodextrins. J Mol Biol 2010; 403:739-50. [DOI: 10.1016/j.jmb.2010.09.031] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/08/2010] [Accepted: 09/15/2010] [Indexed: 11/21/2022]
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23
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Sohajda T, Béni S, Varga E, Iványi R, Rácz Á, Szente L, Noszál B. Characterization of aspartame–cyclodextrin complexation. J Pharm Biomed Anal 2009; 50:737-45. [DOI: 10.1016/j.jpba.2009.06.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 06/04/2009] [Accepted: 06/05/2009] [Indexed: 11/28/2022]
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