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Polańska O, Szulc N, Stottko R, Olek M, Nadwodna J, Gąsior-Głogowska M, Szefczyk M. Challenges in Peptide Solubilization - Amyloids Case Study. CHEM REC 2024:e202400053. [PMID: 39023378 DOI: 10.1002/tcr.202400053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/23/2024] [Indexed: 07/20/2024]
Abstract
Peptide science has been a rapidly growing research field because of the enormous potential application of these biocompatible and bioactive molecules. However, many factors limit the widespread use of peptides in medicine, and low solubility is among the most common problems that hamper drug development in the early stages of research. Solubility is a crucial, albeit poorly understood, feature that determines peptide behavior. Several different solubility predictors have been proposed, and many strategies and protocols have been reported to dissolve peptides, but none of them is a one-size-fits-all method for solubilization of even the same peptide. In this review, we look for the reasons behind the difficulties in dissolving peptides, analyze the factors influencing peptide aggregation, conduct a critical analysis of solubilization strategies and protocols available in the literature, and give some tips on how to deal with the so-called difficult sequences. We focus on amyloids, which are particularly difficult to dissolve and handle such as amyloid beta (Aβ), insulin, and phenol-soluble modulins (PSMs).
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Affiliation(s)
- Oliwia Polańska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370, Wroclaw, Poland
| | - Natalia Szulc
- Department of Physics and Biophysics, Wroclaw University of Environmental and Life Sciences, Norwida 25, 50-375, Wrocław, Poland
| | - Rafał Stottko
- Faculty of Chemistry, Wrocław University of Science and Technology, Gdanska 7/9, 50-344, Wrocław, Poland
| | - Mateusz Olek
- Faculty of Medical Sciences in Zabrze, Medical University of Silesia in Katowice, Traugutta 2, 41-800 Zabrze, Poland
| | - Julita Nadwodna
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370, Wroclaw, Poland
| | - Marlena Gąsior-Głogowska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370, Wroclaw, Poland
| | - Monika Szefczyk
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370, Wroclaw, Poland
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2
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Effect of C-Terminus Modification in Salmonella typhimurium FliC on Protein Purification Efficacy and Bioactivity. Mol Biotechnol 2018; 61:12-19. [DOI: 10.1007/s12033-018-0135-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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3
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Jeyaharan D, Aston P, Garcia-Perez A, Schouten J, Davis P, Dixon AM. Soluble expression, purification and functional characterisation of carboxypeptidase G2 and its individual domains. Protein Expr Purif 2016; 127:44-52. [PMID: 27374188 DOI: 10.1016/j.pep.2016.06.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/27/2016] [Accepted: 06/29/2016] [Indexed: 11/24/2022]
Abstract
Due to its applications in the treatment of cancer and autoimmune diseases, the 42 kDa zinc-dependent metalloenzyme carboxypeptidase G2 (CPG2) is of great therapeutic interest. An X-ray crystal structure of unliganded CPG2 reported in 1997 revealed the domain architecture and informed early rational drug design efforts, however further efforts at co-crystallization of CPG2 with ligands, substrates or inhibitors have not been reported. Thus key features of CPG2 such as the location of the active site, the presence of additional ligand-binding sites, stability, oligomeric state, and the molecular basis of activity remain largely unknown, with the current working understanding of CPG2 activity based primarily on computational modelling. To facilitate renewed efforts in CPG2 structural biology, we report the first high-yield (250 mg L(-1)) recombinant expression (and purification) of soluble and active CPG2 using the Escherichia coli expression system. We used this protocol to produce full-length enzyme, as well as protein fragments corresponding to the individual catalytic and dimerization domains, and the activity and stability of each construct was characterised. We adapted our protocol to allow for uniform incorporation of NMR labels ((13)C, (15)N and (2)H) and present preliminary solution-state NMR spectra of high quality. Taken together, our results offer a route for production and solution-state characterization that supports renewed effort in CPG2 structural biology as well as design of significantly truncated CPG2 proteins, which retain activity while yielding (potentially) improved immunogenicity.
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Affiliation(s)
| | - Philip Aston
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | | | - James Schouten
- Mologic Ltd, Bedford Technology Park, Thurleigh, Bedford, MK44 2YP, UK
| | - Paul Davis
- Mologic Ltd, Bedford Technology Park, Thurleigh, Bedford, MK44 2YP, UK
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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4
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Frueh DP. Practical aspects of NMR signal assignment in larger and challenging proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 78:47-75. [PMID: 24534088 PMCID: PMC3951217 DOI: 10.1016/j.pnmrs.2013.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 12/05/2013] [Accepted: 12/06/2013] [Indexed: 05/03/2023]
Abstract
NMR has matured into a technique routinely employed for studying proteins in near physiological conditions. However, applications to larger proteins are impeded by the complexity of the various correlation maps necessary to assign NMR signals. This article reviews the data analysis techniques traditionally employed for resonance assignment and describes alternative protocols necessary for overcoming challenges in large protein spectra. In particular, simultaneous analysis of multiple spectra may help overcome ambiguities or may reveal correlations in an indirect manner. Similarly, visualization of orthogonal planes in a multidimensional spectrum can provide alternative assignment procedures. We describe examples of such strategies for assignment of backbone, methyl, and nOe resonances. We describe experimental aspects of data acquisition for the related experiments and provide guidelines for preliminary studies. Focus is placed on large folded monomeric proteins and examples are provided for 37, 48, 53, and 81 kDa proteins.
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Affiliation(s)
- Dominique P Frueh
- Johns Hopkins University School of Medicine, Biophysics and Biophysical Chemistry, 725 N. Wolfe Street, 701 Hunterian, Baltimore, MD 21205-2105, United States.
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5
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Morris AL, Harrison CR. Adsorption of buffer ion pairs can alter long-term electroosmotic flow stability. Electrophoresis 2013; 34:2585-92. [DOI: 10.1002/elps.201200687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/15/2013] [Accepted: 05/05/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Ashley L. Morris
- Department of Chemistry and Biochemistry; San Diego State University; San Diego CA USA
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6
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Sibille N, Bellot G, Wang J, Déméné H. Low concentration of a Gd-chelate increases the signal-to-noise ratio in fast pulsing BEST experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 224:32-37. [PMID: 23010449 DOI: 10.1016/j.jmr.2012.07.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 07/17/2012] [Accepted: 07/31/2012] [Indexed: 06/01/2023]
Abstract
Despite numerous developments in the past few years that aim to increase the sensitivity of NMR multidimensional experiments, NMR spectroscopy still suffers from intrinsic low sensitivity. In this report, we show that the combination of two developments in the field, the Band-selective Excitation Short-Transient (BEST) experiment [Schanda et al., J. Am. Chem. Soc., 128 (2006) 9042] and the addition of the nonionic paramagnetic gadolinium chelate gadodiamide into NMR samples, enhances the signal-to-noise ratio. This effect is shown here for four different proteins, three globular and one unfolded, of molecular weights ranging from 6.5 kDa to 40 kDa, using 2D BEST HSQC and 3D BEST triple resonance sequences. Moreover, we show that the increase in signal-to-noise ratio provided by the gadodiamide is higher for peak resonances with lower than average intensity in BEST experiments. It is interesting to note that these residues are on average the weakest ones in those experiments. In this case, the gadodiamide-mediated increase can reach a value of 60% for low and 30% for high molecular weight proteins respectively. An investigation into the origin of this "paramagnetic gain" in BEST experiments is presented.
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Affiliation(s)
- Nathalie Sibille
- CNRS UMR 5048, Centre de Biochimie Structurale, Montpellier, France
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7
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Vazquez E, Corchero JL, Villaverde A. Post-production protein stability: trouble beyond the cell factory. Microb Cell Fact 2011; 10:60. [PMID: 21806813 PMCID: PMC3162505 DOI: 10.1186/1475-2859-10-60] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 08/01/2011] [Indexed: 12/21/2022] Open
Abstract
Being protein function a conformation-dependent issue, avoiding aggregation during production is a major challenge in biotechnological processes, what is often successfully addressed by convenient upstream, midstream or downstream approaches. Even when obtained in soluble forms, proteins tend to aggregate, especially if stored and manipulated at high concentrations, as is the case of protein drugs for human therapy. Post-production protein aggregation is then a major concern in the pharmaceutical industry, as protein stability, pharmacokinetics, bioavailability, immunogenicity and side effects are largely dependent on the extent of aggregates formation. Apart from acting at the formulation level, the recombinant nature of protein drugs allows intervening at upstream stages through protein engineering, to produce analogue protein versions with higher stability and enhanced therapeutic values.
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Affiliation(s)
- Esther Vazquez
- Institute for Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
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8
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Bellot G, Pascal R, Mendre C, Urbach S, Mouillac B, Déméné H. Expression, purification and NMR characterization of the cyclic recombinant form of the third intracellular loop of the vasopressin type 2 receptor. Protein Expr Purif 2011; 78:131-8. [PMID: 21575724 DOI: 10.1016/j.pep.2011.04.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 04/22/2011] [Accepted: 04/30/2011] [Indexed: 11/25/2022]
Abstract
The vasopressin type 2 (V2R) receptor belongs to the class of G-protein coupled receptors. It is mainly expressed in the membrane of kidney tubules, where it is activated by the extracellular arginine vasopressin. In men, inactivating and activating mutations cause nephrogenic diabetes insipidus and the nephrogenic syndrome of inappropriate antidiuresis respectively. Like most GPCRs, V2R's third intracellular loop (V2R-i3) is involved in the binding and activation of its major effector, the GαS protein. We overexpressed the V2R₂₂₄₋₂₇₄ fragment corresponding to V2R-i3 as a fusion protein with thioredoxin A at the N-terminus and a hexahistidine tag between the two proteins. Recombinant V2R-i3 was designed to harbor N- and C-terminal cysteines, in order to introduce a disulfide bond between N- and C-terminal extremities and hence reproduce the hairpin fold presumably present in the full-length receptor. The fusion protein was produced as inclusion bodies in Escherichia coli and purified by nickel affinity chromatography under denaturing conditions. After a refolding step, thioredoxin and hexahistidine tags were specifically cleaved with the tobacco etch virus protease. The hydrolysis yield, initially very low, increased up to 80% thanks to optimization of buffers and refolding methods. The cleaved fragment, V2₂₂₄₋₂₇₄, devoid of any tag, was then eluted with low imidazole concentrations in a second nickel affinity chromatography in denaturing conditions. The final yield was sufficient to prepare a ¹⁵N-¹³C labeled NMR sample suitable for triple resonance experiments. We assigned all NMR resonances and confirmed the correct peptide sequence. As expected, the peptide forms a hairpin stabilized by a disulfide bond between its N- and C-terminal parts, thus mimicking its native structure in the full-length receptor. This study may provide a strategy for producing and studying the structure/function relationship of GPCR fragments.
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Affiliation(s)
- Gaëtan Bellot
- INSERM U1054, Centre de Biochimie Structurale, 29 Rue de Navacelles, 34090 Montpellier Cedex, France
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Kwan AH, Mobli M, Gooley PR, King GF, Mackay JP. Macromolecular NMR spectroscopy for the non-spectroscopist. FEBS J 2011; 278:687-703. [PMID: 21214860 DOI: 10.1111/j.1742-4658.2011.08004.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
NMR spectroscopy is a powerful tool for studying the structure, function and dynamics of biological macromolecules. However, non-spectroscopists often find NMR theory daunting and data interpretation nontrivial. As the first of two back-to-back reviews on NMR spectroscopy aimed at non-spectroscopists, the present review first provides an introduction to the basics of macromolecular NMR spectroscopy, including a discussion of typical sample requirements and what information can be obtained from simple NMR experiments. We then review the use of NMR spectroscopy for determining the 3D structures of macromolecules and examine how to judge the quality of NMR-derived structures.
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Affiliation(s)
- Ann H Kwan
- School of Molecular Bioscience, University of Sydney, New South Wales, Australia
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10
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Ahmad SS, Dalby PA. Thermodynamic parameters for salt-induced reversible protein precipitation from automated microscale experiments. Biotechnol Bioeng 2010; 108:322-32. [DOI: 10.1002/bit.22957] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Sugiki T, Yoshiura C, Kofuku Y, Ueda T, Shimada I, Takahashi H. High-throughput screening of optimal solution conditions for structural biological studies by fluorescence correlation spectroscopy. Protein Sci 2009; 18:1115-20. [PMID: 19388076 PMCID: PMC2771313 DOI: 10.1002/pro.92] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/27/2009] [Accepted: 02/02/2009] [Indexed: 11/07/2022]
Abstract
Protein aggregation is an essential molecular event in a wide variety of biological situations, and is a causal factor in several degenerative diseases. The aggregation of proteins also frequently hampers structural biological analyses, such as solution NMR studies. Therefore, precise detection and characterization of protein aggregation are of crucial importance for various research fields. In this study, we demonstrate that fluorescence correlation spectroscopy (FCS) using a single-molecule fluorescence detection system enables the detection of otherwise invisible aggregation of proteins at higher protein concentrations, which are suitable for structural biological experiments, and consumes relatively small amounts of protein over a short measurement time. Furthermore, utilizing FCS, we established a method for high-throughput screening of protein aggregation and optimal solution conditions for structural biological experiments.
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Affiliation(s)
- Toshihiko Sugiki
- Japan Biological Informatics Consortium (JBiC)Aomi, Koto-ku, Tokyo 135-8073, Japan
- Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST)Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Chie Yoshiura
- Graduate School of Pharmaceutical Sciences, the University of TokyoHongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yutaka Kofuku
- Graduate School of Pharmaceutical Sciences, the University of TokyoHongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takumi Ueda
- Graduate School of Pharmaceutical Sciences, the University of TokyoHongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ichio Shimada
- Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST)Aomi, Koto-ku, Tokyo 135-0064, Japan
- Graduate School of Pharmaceutical Sciences, the University of TokyoHongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hideo Takahashi
- Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST)Aomi, Koto-ku, Tokyo 135-0064, Japan
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12
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Bellot G, Granier S, Bourguet W, Seyer R, Rahmeh R, Mouillac B, Pascal R, Mendre C, Déméné H. Structure of the third intracellular loop of the vasopressin V2 receptor and conformational changes upon binding to gC1qR. J Mol Biol 2009; 388:491-507. [PMID: 19285506 DOI: 10.1016/j.jmb.2009.02.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 12/23/2008] [Accepted: 02/27/2009] [Indexed: 11/19/2022]
Abstract
The V2 vasopressin receptor is a G-protein-coupled receptor that regulates the renal antidiuretic response. Its third intracellular loop is involved in the coupling not only with the GalphaS protein but also with gC1qR, a potential chaperone of G-protein-coupled receptors. In this report, we describe the NMR solution structure of the V2 i3 loop under a cyclized form (i3_cyc) and characterize its interaction with gC1qR. i3_cyc formed a left-twisted alpha-helical hairpin structure. The building of a model of the entire V2 receptor including the i3_cyc NMR structure clarified the side-chain orientation of charged residues, in agreement with literature mutagenesis reports. In the model, the i3 loop formed a rigid helical column, protruding deep inside the cytoplasm, as does the i3 loop in the recently elucidated structure of squid rhodopsin. However, its higher packing angle resulted in a different structural motif at the intracellular interface, which may be important for the specific recognition of GalphaS. Moreover, we could estimate the apparent K(d) of the i3_cyc/gC1qR complex by anisotropy fluorescence. Using a shorter and more soluble version of i3_cyc, which encompassed the putative site of gC1qR binding, we showed by NMR saturation transfer difference spectroscopy that the binding surface corresponded to the central arginine cluster. Binding to gC1qR induced the folding of the otherwise disordered short peptide into a spiral-like path formed by a succession of I and IV turns. Our simulations suggested that this folding would rigidify the arginine cluster in the entire i3 loop and would alter the conformation of the cytosolic extensions of TM V and TM VI helices. In agreement with this conformational rearrangement, we observed that binding of gC1qR to the full-length receptor modifies the intrinsic tryptophan fluorescence binding curves of V2 to an antagonist.
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Abstract
The major challenges in formulation development for hydrophobic proteins are low solubility often combined with a strong tendency for adsorption. Human serum albumin (HSA) is frequently used as excipient to overcome these problems. Due to several drawbacks with HSA, new ways need to be found to circumvent the use of this excipient in protein formulations. One possible approach is to select an appropriate formulation pH and ionic strength in combination with excipients that provide sufficient stability and solubility for the hydrophobic protein. A reduction in adsorption can be achieved by adding surfactants or using special containers.
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Affiliation(s)
- Andrea Hawe
- Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians-University of Munich, Munich, Germany.
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14
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Benoit I, Coutard B, Oubelaid R, Asther M, Bignon C. Expression in Escherichia coli, refolding and crystallization of Aspergillus niger feruloyl esterase A using a serial factorial approach. Protein Expr Purif 2007; 55:166-74. [PMID: 17533138 DOI: 10.1016/j.pep.2007.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/23/2007] [Accepted: 04/01/2007] [Indexed: 11/19/2022]
Abstract
Hydrolysis of plant biomass is achieved by the combined action of enzymes secreted by microorganisms and directed against the backbone and the side chains of plant cell wall polysaccharides. Among side chains degrading enzymes, the feruloyl esterase A (FAEA) specifically removes feruloyl residues. Thus, FAEA has potential applications in a wide range of industrial processes such as paper bleaching or bio-ethanol production. To gain insight into FAEA hydrolysis activity, we solved its crystal structure. In this paper, we report how the use of four consecutive factorial approaches (two incomplete factorials, one sparse matrix, and one full factorial) allowed expressing in Escherichia coli, refolding and then crystallizing Aspergillus niger FAEA in 6 weeks. Culture conditions providing the highest expression level were determined using an incomplete factorial approach made of 12 combinations of four E. coli strains, three culture media and three temperatures (full factorial: 36 combinations). Aspergillus niger FAEA was expressed in the form of inclusion bodies. These were dissolved using a chaotropic agent, and the protein was purified by affinity chromatography on Ni column under denaturing conditions. A suitable buffer for refolding the protein eluted from the Ni column was found using a second incomplete factorial approach made of 96 buffers (full factorial: 3840 combinations). After refolding, the enzyme was further purified by gel filtration, and then crystallized following a standard protocol: initial crystallization conditions were found using commercial crystallization screens based on a sparse matrix. Crystals were then optimized using a full factorial screen.
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Affiliation(s)
- Isabelle Benoit
- UMR 1163 INRA de Biotechnologie des Champignons Filamenteux, IFR86-BAIM, Université de Provence et de la Méditerranée, ESIL, 163 avenue de Luminy CP 925, 13288 Marseille cedex 09, France
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15
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Mal TK, Takahata S, Ki S, Zheng L, Kokubo T, Ikura M. Functional silencing of TATA-binding protein (TBP) by a covalent linkage of the N-terminal domain of TBP-associated factor 1. J Biol Chem 2007; 282:22228-38. [PMID: 17553784 DOI: 10.1074/jbc.m702988200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
General transcription factor TFIID is comprised of TATA-binding protein (TBP) and TBP-associated factors (TAFs), together playing critical roles in regulation of transcription initiation. The TAF N-terminal domain (TAND) of yeast TAF1 containing two subdomains, TAND1 (residues 10-37) and TAND2 (residues 46-71), is sufficient to interact with TBP and suppress the TATA binding activity of TBP. However, the detailed structural analysis of the complex between yeast TBP and TAND12 (residues 6-71) was hindered by its poor solubility and stability in solution. Here we report a molecular engineering approach where the N terminus of TBP is fused to the C terminus of TAND12 via linkers of various lengths containing (GGGS)(n) sequence, (n = 1, 2, 3). The length of the linker within the TAND12-TBP fusion has a significant effect on solubility and stability (SAS). The construct with (GGGS)(3) linker produces the best quality single-quantum-coherence (HSQC) NMR spectrum with markedly improved SAS. In parallel to these observations, the TAND12-TBP fusion exhibits marked reduction of TBP function in binding to TAF1 as well as temperature sensitivity in in vivo yeast cell growth. Remarkably, the temperature sensitivity was proportional to the length of the linker in the fusions: the construct with (GGGS)(3) linker did not grow at 20 degrees C, while those with (GGGS)(1) and (GGGS)(2) linkers did. These results together indicate that the native interaction between TBP and TAND12 is well maintained in the TAND12-(GGGS)(3)-TBP fusion and that this fusion approach provides an excellent model system to investigate the structural detail of the TBP-TAF1 interaction.
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Affiliation(s)
- Tapas K Mal
- Division of Signaling Biology, Ontario Cancer Institute, Department of Medical Biophysics, University of Toronto, Toronto Medical Discovery Towers, Toronto, Ontario, Canada
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