1
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Saxena VK, Vedamurthy G, Singh R. A novel concept of Pyridoxal 5'-phosphate permeability in E.coli for modulating the heterologous expression of PLP dependent proteins. Process Biochem 2022. [DOI: 10.1016/j.procbio.2021.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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2
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Chakraborty T, Polley S, Sinha D, Seal S, Sinha D, Mitra SK, Hazra J, Sau K, Pal M, Sau S. Structurally distinct unfolding intermediates formed from a staphylococcal capsule-producing enzyme retained NADPH binding activity. J Biomol Struct Dyn 2021; 40:9126-9143. [PMID: 33977860 DOI: 10.1080/07391102.2021.1924269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
CapF, a capsule-producing enzyme expressed by Staphylococcus aureus, binds NADPH and exists as a dimer in the aqueous solution. Many other capsule-producing virulent bacteria also express CapF orthologs. To understand the folding-unfolding mechanism of S. aureus CapF, herein a recombinant CapF (rCapF) was individually investigated using urea and guanidine hydrochloride (GdnCl). Unfolding of rCapF by both the denaturants was reversible but proceeded via the synthesis of a different number of intermediates. While two dimeric intermediates (rCapF4 and rCapF5) were formed at 0.5 M and 1.5 M GdnCl, three dimeric intermediates (rCapF1, rCapF2, and rCapF3) were produced at 1 M, 2 M, and 3 M urea, respectively. rCapF5 showed 3.6 fold less NADPH binding activity, whereas other intermediates retained full NADPH binding activity. Compared to rCapF, all of the intermediates (except rCapF3) had a compressed shape. Conversely, rCapF3 possessed a native protein-like shape. The maximum shape loss was in rCapF4 though its secondary structure remained unperturbed. Additionally, the tertiary structure and hydrophobic surface area of the intermediates neither matched with each other nor with those of the native rCapF. Of the four Trp residues in rCapF, one or more Trp residues in the intermediates may have higher solvent accessibility. Using sequence alignment and a tertiary structural model of CapF, we have demonstrated that the region around Trp 137 of CapF may be most sensitive to unfolding, whereas the NADPH binding motif carrying region at the N-terminal end of this protein may be resistant to unfolding, particularly at the low denaturant concentrations.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Soumitra Polley
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Debabrata Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Soham Seal
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Debasmita Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Sudip K Mitra
- Department of Biotechnology, Haldia Institute of Technology, Haldia, West Bengal, India
| | - Joyita Hazra
- Division of Molecular Medicine, Bose Institute, Kolkata, West Bengal, India
| | - Keya Sau
- Department of Biotechnology, Haldia Institute of Technology, Haldia, West Bengal, India
| | - Mahadeb Pal
- Division of Molecular Medicine, Bose Institute, Kolkata, West Bengal, India
| | - Subrata Sau
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
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3
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Ruggieri F, Campillo-Brocal JC, Chen S, Humble MS, Walse B, Logan DT, Berglund P. Insight into the dimer dissociation process of the Chromobacterium violaceum (S)-selective amine transaminase. Sci Rep 2019; 9:16946. [PMID: 31740704 PMCID: PMC6861513 DOI: 10.1038/s41598-019-53177-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
One of the main factors hampering the implementation in industry of transaminase-based processes for the synthesis of enantiopure amines is their often low storage and operational stability. Our still limited understanding of the inactivation processes undermining the stability of wild-type transaminases represents an obstacle to improving their stability through enzyme engineering. In this paper we present a model describing the inactivation process of the well-characterized (S)-selective amine transaminase from Chromobacterium violaceum. The cornerstone of the model, supported by structural, computational, mutagenesis and biophysical data, is the central role of the catalytic lysine as a conformational switch. Upon breakage of the lysine-PLP Schiff base, the strain associated with the catalytically active lysine conformation is dissipated in a slow relaxation process capable of triggering the known structural rearrangements occurring in the holo-to-apo transition and ultimately promoting dimer dissociation. Due to the occurrence in the literature of similar PLP-dependent inactivation models valid for other non-transaminase enzymes belonging to the same fold-class, the role of the catalytic lysine as conformational switch might extend beyond the transaminase enzyme group and offer new insight to drive future non-trivial engineering strategies.
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Affiliation(s)
- Federica Ruggieri
- Department of Industrial Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, SE-106 91, Stockholm, Sweden
- SARomics Biostructures AB, Medicon Village, SE-223 81, Lund, Sweden
| | - Jonatan C Campillo-Brocal
- Department of Industrial Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, SE-106 91, Stockholm, Sweden
| | - Shan Chen
- Department of Industrial Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, SE-106 91, Stockholm, Sweden
| | - Maria S Humble
- Pharem Biotech AB, Biovation Park, SE-151 36, Södertälje, Sweden
| | - Björn Walse
- SARomics Biostructures AB, Medicon Village, SE-223 81, Lund, Sweden
| | - Derek T Logan
- SARomics Biostructures AB, Medicon Village, SE-223 81, Lund, Sweden
| | - Per Berglund
- Department of Industrial Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, SE-106 91, Stockholm, Sweden.
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4
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Verma K, Kundu D, Kundu LM, Singh AK, Dubey VK. Folding and stability of recombinant azoreductase enzyme from Chromobacterium violaceum. Enzyme Microb Technol 2019; 131:109433. [PMID: 31615666 DOI: 10.1016/j.enzmictec.2019.109433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/30/2019] [Accepted: 09/17/2019] [Indexed: 10/26/2022]
Abstract
Azoreductase from Chromobacterium violaceum was characterized biophysically using experimental and computational tools. The in-silico docking and cross-linking experiments using glutaraldehyde suggest dimeric nature of the enzyme. The enzyme structure was modelled and also studied using circular dichroism (CD) spectroscopy which suggests 40% α- helix, 30% β- sheet and 30% random coils. In the modelled structure of the azoreductase, the cofactor flavin mononucleotide (FMN) binding energy was -3.8 kJ/mol. The binding of FMN affects the azoreductase-cofactor complex stability. The stability-folding studies indicate that the cofactor, FMN is required for folding, stability and activity. Overall, the data provides interesting insight into stability and biophysical parameters of the azoreductase protein.
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Affiliation(s)
- Kamalesh Verma
- Centre for the Environment, Indian Institute of Technology Guwahati, Assam 781039, India
| | - Debanjan Kundu
- School of Biochemical Engineering, Indian Institute of Technology (BHU) Varanasi, Uttar Pradesh 221005, India
| | - Lal Mohan Kundu
- Centre for the Environment, Indian Institute of Technology Guwahati, Assam 781039, India; Department of Chemistry, Institute of Technology Guwahati, Assam 781039, India
| | - Ashish Kumar Singh
- School of Biochemical Engineering, Indian Institute of Technology (BHU) Varanasi, Uttar Pradesh 221005, India
| | - Vikash Kumar Dubey
- Centre for the Environment, Indian Institute of Technology Guwahati, Assam 781039, India; School of Biochemical Engineering, Indian Institute of Technology (BHU) Varanasi, Uttar Pradesh 221005, India.
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5
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Conter C, Oppici E, Dindo M, Rossi L, Magnani M, Cellini B. Biochemical properties and oxalate-degrading activity of oxalate decarboxylase from bacillus subtilis at neutral pH. IUBMB Life 2019; 71:917-927. [PMID: 30806021 PMCID: PMC6850040 DOI: 10.1002/iub.2027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 01/14/2019] [Accepted: 01/29/2019] [Indexed: 11/05/2022]
Abstract
Oxalate decarboxylase (OxDC) from Bacillus subtilis is a Mn-dependent hexameric enzyme that converts oxalate to carbon dioxide and formate. OxDC has greatly attracted the interest of the scientific community, mainly due to its biotechnological and medical applications in particular for the treatment of hyperoxaluria, a group of pathologic conditions caused by oxalate accumulation. The enzyme has an acidic optimum pH, but most of its applications involve processes occurring at neutral pH. Nevertheless, a detailed biochemical characterization of the enzyme at neutral pH is lacking. Here, we compared the structural-functional properties at acidic and neutral pH of wild-type OxDC and of a mutant form, called OxDC-DSSN, bearing four amino acid substitutions in the lid (Ser161-to-Asp, Glu162-to-Ser, Asn163-toSer, and Ser164-to-Asn) that improve the oxalate oxidase activity and almost abolish the decarboxylase activity. We found that both enzymatic forms do not undergo major structural changes as a function of pH, although OxDC-DSSN displays an increased tendency to aggregation, which is counteracted by the presence of an active-site ligand. Notably, OxDC and OxDC-DSSN at pH 7.2 retain 7 and 15% activity, respectively, which is sufficient to degrade oxalate in a cellular model of primary hyperoxaluria type I, a rare inherited disease caused by excessive endogenous oxalate production. The significance of the data in the light of the possible use of OxDC as biological drug is discussed. © 2019 IUBMB Life, 1-11, 2019.
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Affiliation(s)
- Carolina Conter
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Verona, Italy
| | - Elisa Oppici
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Verona, Italy
| | - Mirco Dindo
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Barbara Cellini
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
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6
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Ma W, Cao W, Zhang B, Chen K, Liu Q, Li Y, Ouyang P. Engineering a pyridoxal 5'-phosphate supply for cadaverine production by using Escherichia coli whole-cell biocatalysis. Sci Rep 2015; 5:15630. [PMID: 26490441 PMCID: PMC4614675 DOI: 10.1038/srep15630] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/29/2015] [Indexed: 01/24/2023] Open
Abstract
Although the routes of de novo pyridoxal 5′-phosphate (PLP) biosynthesis have been well described, studies of the engineering of an intracellular PLP supply are limited, and the effects of cellular PLP levels on PLP-dependent enzyme-based whole-cell biocatalyst activity have not been described. To investigate the effects of PLP cofactor availability on whole-cell biocatalysis, the ribose 5-phosphate (R5P)-dependent pathway genes pdxS and pdxT of Bacillus subtilis were introduced into the lysine decarboxylase (CadA)-overexpressing Escherichia coli strain BL-CadA. This strain was then used as a whole-cell biocatalyst for cadaverine production from L-lysine. Co-expression strategies were evaluated, and the culture medium was optimised to improve the biocatalyst performance. As a result, the intracellular PLP concentration reached 1144 nmol/gDCW, and a specific cadaverine productivity of 25 g/gDCW/h was achieved; these values were 2.4-fold and 2.9-fold higher than those of unmodified BL-CadA, respectively. Additionally, the resulting strain AST3 showed a cadaverine titre (p = 0.143, α = 0.05) similar to that of the BL-CadA strain with the addition of 0.1 mM PLP. These approaches for improving intracellular PLP levels to enhance whole-cell lysine bioconversion activity show great promise for the engineering of a PLP cofactor to optimise whole-cell biocatalysis.
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Affiliation(s)
- Weichao Ma
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Bioengineering and Biotechnology, Tianshui Normal University, Tianshui 741001, P.R. China
| | - Weijia Cao
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China
| | - Bowen Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China
| | - Kequan Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China
| | - Quanzhen Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China
| | - Yan Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China
| | - Pingkai Ouyang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China
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7
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Grosch JH, Loderer C, Jestel T, Ansorge-Schumacher M, Spieß AC. Carbonyl reductase of Candida parapsilosis – Stability analysis and stabilization strategy. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2014.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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The chaperone role of the pyridoxal 5′-phosphate and its implications for rare diseases involving B6-dependent enzymes. Clin Biochem 2014; 47:158-65. [DOI: 10.1016/j.clinbiochem.2013.11.021] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/28/2013] [Accepted: 11/30/2013] [Indexed: 02/06/2023]
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9
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Bishop DF, Tchaikovskii V, Hoffbrand AV, Fraser ME, Margolis S. X-linked sideroblastic anemia due to carboxyl-terminal ALAS2 mutations that cause loss of binding to the β-subunit of succinyl-CoA synthetase (SUCLA2). J Biol Chem 2012; 287:28943-55. [PMID: 22740690 PMCID: PMC3436539 DOI: 10.1074/jbc.m111.306423] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Indexed: 11/06/2022] Open
Abstract
Mutations in the erythroid-specific aminolevulinic acid synthase gene (ALAS2) cause X-linked sideroblastic anemia (XLSA) by reducing mitochondrial enzymatic activity. Surprisingly, a patient with the classic XLSA phenotype had a novel exon 11 mutation encoding a recombinant enzyme (p.Met567Val) with normal activity, kinetics, and stability. Similarly, both an expressed adjacent XLSA mutation, p.Ser568Gly, and a mutation (p.Phe557Ter) lacking the 31 carboxyl-terminal residues also had normal or enhanced activity, kinetics, and stability. Because ALAS2 binds to the β subunit of succinyl-CoA synthetase (SUCLA2), the mutant proteins were tested for their ability to bind to this protein. Wild type ALAS2 bound strongly to a SUCLA2 affinity column, but the adjacent XLSA mutant enzymes and the truncated mutant did not bind. In contrast, vitamin B6-responsive XLSA mutations p.Arg452Cys and p.Arg452His, with normal in vitro enzyme activity and stability, did not interfere with binding to SUCLA2 but instead had loss of positive cooperativity for succinyl-CoA binding, an increased K(m) for succinyl-CoA, and reduced vitamin B6 affinity. Consistent with the association of SUCLA2 binding with in vivo ALAS2 activity, the p.Met567GlufsX2 mutant protein that causes X-linked protoporphyria bound strongly to SUCLA2, highlighting the probable role of an ALAS2-succinyl-CoA synthetase complex in the regulation of erythroid heme biosynthesis.
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Affiliation(s)
- David F. Bishop
- From the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - Vassili Tchaikovskii
- From the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - A. Victor Hoffbrand
- the Department of Haematology, Royal Free Hospital, London NW3 2QG, United Kingdom, and
| | - Marie E. Fraser
- the Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Steven Margolis
- From the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
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10
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Tanous C, Soutourina O, Raynal B, Hullo MF, Mervelet P, Gilles AM, Noirot P, Danchin A, England P, Martin-Verstraete I. The CymR regulator in complex with the enzyme CysK controls cysteine metabolism in Bacillus subtilis. J Biol Chem 2008; 283:35551-60. [PMID: 18974048 DOI: 10.1074/jbc.m805951200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Several enzymes have evolved as sensors in signal transduction pathways to control gene expression, thereby allowing bacteria to adapt efficiently to environmental changes. We recently identified the master regulator of cysteine metabolism in Bacillus subtilis, CymR, which belongs to the poorly characterized Rrf2 family of regulators. We now report that the signal transduction mechanism controlling CymR activity in response to cysteine availability involves the formation of a stable complex with CysK, a key enzyme for cysteine biosynthesis. We carried out a comprehensive quantitative characterization of this regulator-enzyme interaction by surface plasmon resonance and analytical ultracentrifugation. We also showed that O-acetylserine plays a dual role as a substrate of CysK and as an effector modulating the CymR-CysK complex formation. The ability of B. subtilis CysK to bind to CymR appears to be correlated to the loss of its capacity to form a cysteine synthase complex with CysE. We propose an original model, supported by the determination of the intracellular concentrations of the different partners, by which CysK positively regulates CymR in sensing the bacterial cysteine pool.
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Affiliation(s)
- Catherine Tanous
- Institut Pasteur, UnitédeGénétique des Génomes Bactériens, Plate-forme de Biophysique des Macromolécules et de leurs Interactions, 75724 Paris cedex 15, France
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11
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Hawe A, Sutter M, Jiskoot W. Extrinsic fluorescent dyes as tools for protein characterization. Pharm Res 2008; 25:1487-99. [PMID: 18172579 PMCID: PMC2440933 DOI: 10.1007/s11095-007-9516-9] [Citation(s) in RCA: 872] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 12/05/2007] [Indexed: 11/16/2022]
Abstract
Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization.
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Affiliation(s)
- Andrea Hawe
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marc Sutter
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- Novartis Pharma AG, WSJ-316.4.14, CH-4056 Basel, Switzerland
| | - Wim Jiskoot
- Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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12
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Malerba F, Bellelli A, Giorgi A, Bossa F, Contestabile R. The mechanism of addition of pyridoxal 5'-phosphate to Escherichia coli apo-serine hydroxymethyltransferase. Biochem J 2007; 404:477-85. [PMID: 17341210 PMCID: PMC1896279 DOI: 10.1042/bj20061681] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Previous studies suggest that the addition of pyridoxal 5'-phosphate to apo-serine hydroxymethyltransferase from Escherichia coli is the last event in the enzyme's folding process. We propose a mechanism for this reaction based on quenched-flow, stopped-flow and rapid-scanning stopped-flow experiments. All experiments were performed with an excess of apo-enzyme over cofactor, since excess pyridoxal 5'-phosphate results in a second molecule of cofactor binding to Lys346, which is part of the tetrahydropteroylglutamate-binding site. The equilibrium between the aldehyde and hydrate forms of the cofactor affects the kinetics of addition to the active site. Direct evidence of the formation of an intermediate aldimine between the cofactor and the active-site lysine was obtained. The results have been interpreted according to a three-step mechanism in which: (i) both aldehyde and hydrate forms of the cofactor bind rapidly and non-covalently to the apo-enzyme; (ii) only the aldehyde form reacts with the active-site lysine to give an intermediate internal aldimine with unusual spectral properties; and (iii) a final conformational change gives the native holo-enzyme.
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Affiliation(s)
- Francesca Malerba
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Andrea Bellelli
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Alessandra Giorgi
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Francesco Bossa
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
- To whom correspondence should be addressed (email )
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13
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Cellini B, Bertoldi M, Montioli R, Laurents DV, Paiardini A, Voltattorni CB. Dimerization and Folding Processes of Treponema denticola Cystalysin: The Role of Pyridoxal 5‘-Phosphate. Biochemistry 2006; 45:14140-54. [PMID: 17115709 DOI: 10.1021/bi061496l] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cystalysin, the key virulence factor in the bacterium Treponema denticola responsible for periodontitis, is a homodimeric pyridoxal 5'-phosphate (PLP)-C-S lyase. The dimerization process and the urea-induced unfolding equilibrium of holocystalysin were compared with those of the apo form. The presence of PLP decreases approximately 4 times the monomer-dimer equilibrium dissociation constant. By using a variety of spectroscopic and analytical procedures, we demonstrated a difference in their unfolding profiles. Upon the monomerization of apocystalysin, occurring between 1 and 2 M urea, a self-associated equilibrium intermediate with a very high beta-sheet content is stabilized over the 2.5-4 M urea range, giving rise to a fully unfolded monomer at higher urea concentrations. On the other hand, highly destabilizing conditions, accompanied by the formation of a significant amount of insoluble aggregates, are required for PLP release and monomerization. Refolding studies, together with analysis of the dissociation/association process of cystalysin, shed light on how the protein concentration and the presence or absence of PLP under refolding conditions could affect the recovery of the active dimeric enzyme and the production of insoluble aggregates. When the protein is completely denatured, the best reactivation yield found was approximately 50% and 25% for holo and apocystalysin, respectively. The dimerization and folding processes of cystalysin have been compared with those of another PLP C-S lyase, MalY from E. coli, and the possible relevance of their PLP binding mode in these processes has been discussed.
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Affiliation(s)
- Barbara Cellini
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy
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14
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Jang DS, Lee HJ, Lee B, Hong BH, Cha HJ, Yoon J, Lim K, Yoon YJ, Kim J, Ree M, Lee HC, Choi KY. Detection of an intermediate during the unfolding process of the dimeric ketosteroid isomerase. FEBS Lett 2006; 580:4166-71. [PMID: 16828747 DOI: 10.1016/j.febslet.2006.06.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2006] [Revised: 06/15/2006] [Accepted: 06/23/2006] [Indexed: 10/24/2022]
Abstract
Failure to detect the intermediate in spite of its existence often leads to the conclusion that two-state transition in the unfolding process of the protein can be justified. In contrast to the previous equilibrium unfolding experiment fitted to a two-state model by circular dichroism and fluorescence spectroscopies, an equilibrium unfolding intermediate of a dimeric ketosteroid isomerase (KSI) could be detected by small angle X-ray scattering (SAXS) and analytical ultracentrifugation. The sizes of KSI were determined to be 18.7A in 0M urea, 17.3A in 5.2M urea, and 25.1A in 7M urea by SAXS. The size of KSI in 5.2M urea was significantly decreased compared with those in 0M and 7M urea, suggesting the existence of a compact intermediate. Sedimentation velocity as obtained by ultracentrifugation confirmed that KSI in 5.2M urea is distinctly different from native and fully-unfolded forms. The sizes measured by pulse field gradient nuclear magnetic resonance (NMR) spectroscopy were consistent with those obtained by SAXS. Discrepancy of equilibrium unfolding studies between size measurement methods and optical spectroscopies might be due to the failure in detecting the intermediate by optical spectroscopic methods. Further characterization of the intermediate using (1)H NMR spectroscopy and Kratky plot supported the existence of a partially-folded form of KSI which is distinct from those of native and fully-unfolded KSIs. Taken together, our results suggest that the formation of a compact intermediate should precede the association of monomers prior to the dimerization process during the folding of KSI.
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Affiliation(s)
- Do Soo Jang
- National Research Laboratory of Protein Folding and Engineering, Division of Molecular Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
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