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Miao H, Zhao Y, Ma Y, Han N, Zhe Y, Tang X, Huang Z. Improving the thermostability of endo-β-1,4-glucanase by the fusion of a module subdivided from hyperthermophilic CBM9_1-2. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.01.028] [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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Miao H, Ma Y, Zhe Y, Tang X, Wu Q, Huang Z, Han N. Improving the Thermostability of a Fungal GH11 Xylanase via Fusion of a Submodule (C2) from Hyperthermophilic CBM9_1-2. Int J Mol Sci 2021; 23:ijms23010463. [PMID: 35008888 PMCID: PMC8745443 DOI: 10.3390/ijms23010463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 11/20/2022] Open
Abstract
Xylanases have been applied in many industrial fields. To improve the activity and thermostability of the xylanase CDBFV from Neocallimastix patriciarum (GenBank accession no. KP691331), submodule C2 from hyperthermophilic CBM9_1-2 was inserted into the N- and/or C-terminal regions of the CDBFV protein (producing C2-CDBFV, CDBFV-C2, and C2-CDBFV-C2) by genetic engineering. CDBFV and the hybrid proteins were successfully expressed in Escherichia coli BL21 (DE3). Enzymatic property analysis indicates that the C2 submodule had a significant effect on enhancing the thermostability of the CDBFV. At the optimal temperature (60.0 °C), the half-lives of the three chimeras C2-CDBFV, CDBFV-C2, and C2-CDBFV-C2 are 1.5 times (37.5 min), 4.9 times (122.2 min), and 3.8 times (93.1 min) longer than that of wild-type CDBFV (24.8 min), respectively. More importantly, structural analysis and molecular dynamics (MD) simulation revealed that the improved thermal stability of the chimera CDBFV-C2 was on account of the formation of four relatively stable additional hydrogen bonds (S42-S462, T59-E277, S41-K463, and S44-G371), which increased the protein structure’s stability. The thermostability characteristics of CDBFV-C2 make it a viable enzyme for industrial applications.
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Affiliation(s)
- Huabiao Miao
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming 650500, China; (H.M.); (X.T.); (Q.W.)
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
| | - Yu Ma
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
| | - Yuanyuan Zhe
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
| | - Xianghua Tang
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming 650500, China; (H.M.); (X.T.); (Q.W.)
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
| | - Qian Wu
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming 650500, China; (H.M.); (X.T.); (Q.W.)
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
| | - Zunxi Huang
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming 650500, China; (H.M.); (X.T.); (Q.W.)
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
- Correspondence: (Z.H.); (N.H.); Tel.: +86-0871-5920830 (Z.H.); Fax: +86-0871-5920952 (Z.H.)
| | - Nanyu Han
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Kunming 650500, China; (H.M.); (X.T.); (Q.W.)
- School of Life Science, Yunnan Normal University, Kunming 650500, China; (Y.M.); (Y.Z.)
- Correspondence: (Z.H.); (N.H.); Tel.: +86-0871-5920830 (Z.H.); Fax: +86-0871-5920952 (Z.H.)
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Abady SM, M Ghanem K, Ghanem NB, Embaby AM. Molecular cloning, heterologous expression, and in silico sequence analysis of Enterobacter GH19 class I chitinase (chiRAM gene). Mol Biol Rep 2021; 49:951-969. [PMID: 34773550 DOI: 10.1007/s11033-021-06914-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 10/30/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND Using in silico sequence analyses, the present study aims to clone and express the gene-encoding sequence of a GH19 chitinase from Enterobacter sp. in Escherichia coli. METHODS AND RESULTS The putative open reading frame of a GH19 chitinase from Enterobacter sp. strain EGY1 was cloned and expressed into pGEM®-T and pET-28a (+) vectors, respectively using a degenerate primer. The isolated nucleotide sequence (1821 bp, GenBank accession no.: MK533791.2) was translated to a chiRAM protein (606 amino acids, UniProt accession no.: A0A4D6J2L9). The in silico protein sequence analysis of chiRAM revealed a class I GH19 chitinase: an N-terminus signal peptide (Met1-Ala23), a catalytic domain (Val83-Glu347 and the catalytic triad Glu149, Glu171, and Ser218), a proline-rich hinge region (Pro414 -Pro450), a polycystic kidney disease protein motif (Gly 465-Ser 533), a C-terminus chitin-binding domain (Ala553- Glu593), and conserved class I motifs (NYNY and AQETGG). A three-dimensional model was constructed by LOMETS MODELLER of PDB template: 2dkvA (class I chitinase of Oryza sativa L. japonica). Recombinant chiRAM was overexpressed as inclusion bodies (IBs) (~ 72 kDa; SDS-PAGE) in 1.0 mM IPTG induced E. coli BL21 (DE3) Rosetta strain at room temperature 18 h after induction. Optimized expression yielded active chiRAM with 1.974 ± 0.0002 U/mL, on shrimp colloidal chitin (SCC), in induced E. coli BL21 (DE3) Rosetta cells growing in SB medium. LC-MS/MS identified a band of 72 kDa in the soluble fraction with a 52.3% coverage sequence exclusive to the GH19 chitinase of Enterobacter cloacae (WP_063869339.1). CONCLUSIONS Although chiRAM of Enterobacter sp. was successfully cloned and expressed in E. coli with appreciable chitinase activity, future studies should focus on minimizing IBs to facilitate chiRAM purification and characterization.
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Affiliation(s)
- Shahinaz M Abady
- Department of Botany and Microbiology, Faculty of Science, Alexandria University, 1 Baghdad Street-Moharam Bek, Alexandria, 21568, Egypt
| | - Khaled M Ghanem
- Department of Botany and Microbiology, Faculty of Science, Alexandria University, 1 Baghdad Street-Moharam Bek, Alexandria, 21568, Egypt
| | - Nevine B Ghanem
- Department of Botany and Microbiology, Faculty of Science, Alexandria University, 1 Baghdad Street-Moharam Bek, Alexandria, 21568, Egypt
| | - Amira M Embaby
- Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, P.O.Box 832, 163 Horreya Avenue, Chatby, Alexandria, 21526, Egypt.
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A Novel Actinobacterial Cutinase Containing a Non-Catalytic Polymer-Binding Domain. Appl Environ Microbiol 2021; 88:e0152221. [PMID: 34705546 DOI: 10.1128/aem.01522-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The single putative cutinase-encoding gene from the genome of Kineococcus radiotolerans SRS30216 was cloned and expressed in Escherichia coli as a secreted fusion protein, designated YebF-KrCUT, where YebF is the extracellular carrier protein. The 294-amino acid sequence of KrCUT is unique among currently characterized cutinases by having a C-terminal extension that consists of a short (Pro-Thr)-rich linker and a 55-amino-acid region resembling the substrate binding domain of poly(hydroxybutyrate) (PHB) depolymerases. Phylogenetically, KrCUT takes a unique position among known cutinases and cutinase-like proteins of bacterial and fungal origin. A modeled structure of KrCUT, although displaying a typical α/ß hydrolase fold, shows some unique loops close to the catalytic site. The 39-kDa YebF-KrCUT fusion protein and a truncated variant thereof were purified to electrophoretic homogeneity and functionally characterized. The melting temperatures (Tm) of KrCUT and its variant KrCUT206 devoid of the putative PHB-binding domain were established to be very similar at 50-51°C. Cutinase activity was confirmed by the appearance of characteristic cutin components, C16 and C18 hydroxyl fatty acids, in the mass chromatograms following incubation of KrCUT with apple cutin as substrate. KrCUT also efficiently degraded synthetic polyesters such as polycaprolactone and poly(1,3-propylene adipate). Although incapable of PHB depolymerization, KrCUT could efficiently bind PHB, confirming the predicted characteristic of the C-terminal region. KrCUT also potentiated the activity of pectate lyase in the degradation of pectin from hemp fibres. This synergistic effect is relevant to the enzyme retting process of natural fibres. IMPORTANCE. To date only a limited number of cutinases have been isolated and characterized from nature, the majority being sourced from phytopathogenic fungi and thermophilic bacteria. The significance of our research relates to the identification and characterization of a unique member of microbial cutinases, of name KrCUT, that was derived from the genome of the Gram-positive Kineococcus radiotolerans SRS30216, a highly radiation-resistant actinobacterium. Given the wide-ranging importance of cutinases in applications such as the degradation of natural and synthetic polymers, in the textile industry, in laundry detergents, or in biocatalysis (e.g., transesterification reactions), our results could foster new research leading to broader biotechnological impacts. This study also demonstrated that genome mining or prospecting is a viable means to discover novel biocatalysts as environmentally friendly and biotechnological tool.
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Carratalá JV, Cisneros A, Hellman E, Villaverde A, Ferrer-Miralles N. Title: insoluble proteins catch heterologous soluble proteins into inclusion bodies by intermolecular interaction of aggregating peptides. Microb Cell Fact 2021; 20:30. [PMID: 33531005 PMCID: PMC7852131 DOI: 10.1186/s12934-021-01524-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/21/2021] [Indexed: 02/06/2023] Open
Abstract
Background Protein aggregation is a biological event observed in expression systems in which the recombinant protein is produced under stressful conditions surpassing the homeostasis of the protein quality control system. In addition, protein aggregation is also related to conformational diseases in animals as transmissible prion diseases or non-transmissible neurodegenerative diseases including Alzheimer, Parkinson’s disease, amyloidosis and multiple system atrophy among others. At the molecular level, the presence of aggregation-prone domains in protein molecules act as seeding igniters to induce the accumulation of protein molecules in protease-resistant clusters by intermolecular interactions. Results
In this work we have studied the aggregating-prone performance of a small peptide (L6K2) with additional antimicrobial activity and we have elucidated the relevance of the accompanying scaffold protein to enhance the aggregating profile of the fusion protein. Furthermore, we demonstrated that the fusion of L6K2 to highly soluble recombinant proteins directs the protein to inclusion bodies (IBs) in E. coli through stereospecific interactions in the presence of an insoluble protein displaying the same aggregating-prone peptide (APP). Conclusions These data suggest that the molecular bases of protein aggregation are related to the net balance of protein aggregation potential and not only to the presence of APPs. This is then presented as a generic platform to generate hybrid protein aggregates in microbial cell factories for biopharmaceutical and biotechnological applications.
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Affiliation(s)
- Jose Vicente Carratalá
- Institute for Biotechnology and Biomedicine, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.,Department of Genetics and Microbiology, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.,Bioengineering, Biomaterials and Nanomedicine Networking Biomedical Research Centre (CIBER-BBN), 08193, Bellaterra, Barcelona, Spain
| | - Andrés Cisneros
- Institute for Biotechnology and Biomedicine, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.,Department of Genetics and Microbiology, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Elijah Hellman
- Institute for Biotechnology and Biomedicine, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.,Department of Genetics and Microbiology, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Antonio Villaverde
- Institute for Biotechnology and Biomedicine, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.,Department of Genetics and Microbiology, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.,Bioengineering, Biomaterials and Nanomedicine Networking Biomedical Research Centre (CIBER-BBN), 08193, Bellaterra, Barcelona, Spain
| | - Neus Ferrer-Miralles
- Institute for Biotechnology and Biomedicine, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain. .,Department of Genetics and Microbiology, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain. .,Bioengineering, Biomaterials and Nanomedicine Networking Biomedical Research Centre (CIBER-BBN), 08193, Bellaterra, Barcelona, Spain.
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Hollmann NM, Jagtap PKA, Masiewicz P, Guitart T, Simon B, Provaznik J, Stein F, Haberkant P, Sweetapple LJ, Villacorta L, Mooijman D, Benes V, Savitski MM, Gebauer F, Hennig J. Pseudo-RNA-Binding Domains Mediate RNA Structure Specificity in Upstream of N-Ras. Cell Rep 2020; 32:107930. [PMID: 32697992 PMCID: PMC7383231 DOI: 10.1016/j.celrep.2020.107930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/03/2020] [Accepted: 06/29/2020] [Indexed: 12/12/2022] Open
Abstract
RNA-binding proteins (RBPs) commonly feature multiple RNA-binding domains (RBDs), which provide these proteins with a modular architecture. Accumulating evidence supports that RBP architectural modularity and adaptability define the specificity of their interactions with RNA. However, how multiple RBDs recognize their cognate single-stranded RNA (ssRNA) sequences in concert remains poorly understood. Here, we use Upstream of N-Ras (Unr) as a model system to address this question. Although reported to contain five ssRNA-binding cold-shock domains (CSDs), we demonstrate that Unr includes an additional four CSDs that do not bind RNA (pseudo-RBDs) but are involved in mediating RNA tertiary structure specificity by reducing the conformational heterogeneity of Unr. Disrupting the interactions between canonical and non-canonical CSDs impacts RNA binding, Unr-mediated translation regulation, and the Unr-dependent RNA interactome. Taken together, our studies reveal a new paradigm in protein-RNA recognition, where interactions between RBDs and pseudo-RBDs select RNA tertiary structures, influence RNP assembly, and define target specificity.
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Affiliation(s)
- Nele Merret Hollmann
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | | | - Pawel Masiewicz
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Tanit Guitart
- Gene Regulation, Stem Cells and Cancer Programme, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Bernd Simon
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Jan Provaznik
- Genomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Frank Stein
- Proteomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Per Haberkant
- Proteomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Lara Jayne Sweetapple
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Laura Villacorta
- Genomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Dylan Mooijman
- Developmental Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Vladimir Benes
- Genomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Mikhail M Savitski
- Proteomics Core Facility, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany; Genome Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Fátima Gebauer
- Gene Regulation, Stem Cells and Cancer Programme, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Janosch Hennig
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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7
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A linker of the proline-threonine repeating motif sequence is bimodal. J Mol Model 2020; 26:178. [PMID: 32562031 DOI: 10.1007/s00894-020-04434-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 06/02/2020] [Indexed: 10/24/2022]
Abstract
The linker of the endoglucanase from Xanthomonas campestris pv. campestris ((PT)12) has a specific sequence, a repeating proline-threonine motif. In order to understand its role, it has been compared to a regular sequence linker, in this work-the cellobiohydrolase 2 from Trichoderma reesei (CBH2). Elastic properties of the two linkers have been estimated by calculating free energy profile along the linker length from an enhanced sampling molecular dynamics simulation. The (PT)12 exhibits more pronounced elastic behaviour than CBH2. The PT repeating motif results in a two-mode energy profile which could be very useful in the enzyme motions along the substrate during hydrolytic catalysis.
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Hu B, Zhu M. Reconstitution of cellulosome: Research progress and its application in biorefinery. Biotechnol Appl Biochem 2019; 66:720-730. [DOI: 10.1002/bab.1804] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 08/03/2019] [Indexed: 09/01/2023]
Affiliation(s)
- Bin‐Bin Hu
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals School of Biology and Biological Engineering South China University of Technology, Guangzhou Higher Education Mega Center Panyu Guangzhou People's Republic of China
- Yunnan Academy of Tobacco Agricultural Sciences Kunming People's Republic of China
- State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou People's Republic of China
| | - Ming‐Jun Zhu
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals School of Biology and Biological Engineering South China University of Technology, Guangzhou Higher Education Mega Center Panyu Guangzhou People's Republic of China
- State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou People's Republic of China
- College of Life and Geographic Sciences Kashi University Kashi People's Republic of China
- The Key Laboratory of Ecology and Biological Resources in Yarkand Oasis at Colleges & Universities under the Department of Education of Xinjiang Uygur Autonomous Region Kashi University Kashi People's Republic of China
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Eijsink VGH, Petrovic D, Forsberg Z, Mekasha S, Røhr ÅK, Várnai A, Bissaro B, Vaaje-Kolstad G. On the functional characterization of lytic polysaccharide monooxygenases (LPMOs). BIOTECHNOLOGY FOR BIOFUELS 2019; 12:58. [PMID: 30923566 PMCID: PMC6423801 DOI: 10.1186/s13068-019-1392-0] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/06/2019] [Indexed: 05/02/2023]
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are abundant in nature and best known for their role in the enzymatic conversion of recalcitrant polysaccharides such as chitin and cellulose. LPMO activity requires an oxygen co-substrate, which was originally thought to be O2, but which may also be H2O2. Functional characterization of LPMOs is not straightforward because typical reaction mixtures will promote side reactions, including auto-catalytic inactivation of the enzyme. For example, despite some recent progress, there is still limited insight into the kinetics of the LPMO reaction. Recent discoveries concerning the role of H2O2 in LPMO catalysis further complicate the picture. Here, we review commonly used methods for characterizing LPMOs, with focus on benefits and potential pitfalls, rather than on technical details. We conclude by pointing at a few key problems and potential misconceptions that should be taken into account when interpreting existing data and planning future experiments.
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Affiliation(s)
- Vincent G. H. Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Dejan Petrovic
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Zarah Forsberg
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Sophanit Mekasha
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Åsmund K. Røhr
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Bastien Bissaro
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), PO Box 5003, 1432 Ås, Norway
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Courtade G, Forsberg Z, Heggset EB, Eijsink VGH, Aachmann FL. The carbohydrate-binding module and linker of a modular lytic polysaccharide monooxygenase promote localized cellulose oxidation. J Biol Chem 2018; 293:13006-13015. [PMID: 29967065 DOI: 10.1074/jbc.ra118.004269] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/23/2018] [Indexed: 01/24/2023] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of polysaccharides such as cellulose and chitin, a feature that makes them key tools in industrial biomass conversion processes. The catalytic domains of a considerable fraction of LPMOs and other carbohydrate-active enzymes (CAZymes) are tethered to carbohydrate-binding modules (CBMs) by flexible linkers. These linkers preclude X-ray crystallographic studies, and the functional implications of these modular assemblies remain partly unknown. Here, we used NMR spectroscopy to characterize structural and dynamic features of full-length modular ScLPMO10C from Streptomyces coelicolor We observed that the linker is disordered and extended, creating distance between the CBM and the catalytic domain and allowing these domains to move independently of each other. Functional studies with cellulose nanofibrils revealed that most of the substrate-binding affinity of full-length ScLPMO10C resides in the CBM. Comparison of the catalytic performance of full-length ScLPMO10C and its isolated catalytic domain revealed that the CBM is beneficial for LPMO activity at lower substrate concentrations and promotes localized and repeated oxidation of the substrate. Taken together, these results provide a mechanistic basis for understanding the interplay between catalytic domains linked to CBMs in LPMOs and CAZymes in general.
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Affiliation(s)
- Gaston Courtade
- From NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | - Zarah Forsberg
- the Faculty of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, N-1432 Ås, Norway, and
| | | | - Vincent G H Eijsink
- the Faculty of Chemistry, Biotechnology and Food Science, NMBU Norwegian University of Life Sciences, N-1432 Ås, Norway, and
| | - Finn L Aachmann
- From NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway,
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11
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Prates ET, Guan X, Li Y, Wang X, Chaffey PK, Skaf MS, Crowley MF, Tan Z, Beckham GT. The impact of O-glycan chemistry on the stability of intrinsically disordered proteins. Chem Sci 2018; 9:3710-3715. [PMID: 29780502 PMCID: PMC5939190 DOI: 10.1039/c7sc05016j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/19/2018] [Indexed: 01/14/2023] Open
Abstract
Protein glycosylation is a diverse post-translational modification that serves myriad biological functions. O-linked glycans in particular vary widely in extent and chemistry in eukaryotes, with secreted proteins from fungi and yeast commonly exhibiting O-mannosylation in intrinsically disordered regions of proteins, likely for proteolysis protection, among other functions. However, it is not well understood why mannose is often the preferred glycan, and more generally, if the neighboring protein sequence and glycan have coevolved to protect against proteolysis in glycosylated intrinsically disordered proteins (IDPs). Here, we synthesized variants of a model IDP, specifically a natively O-mannosylated linker from a fungal enzyme, with α-O-linked mannose, glucose, and galactose moieties, along with a non-glycosylated linker. Upon exposure to thermolysin, O-mannosylation, by far, provides the highest extent of proteolysis protection. To explain this observation, extensive molecular dynamics simulations were conducted, revealing that the axial configuration of the C2-hydroxyl group (2-OH) of α-mannose adjacent to the glycan-peptide bond strongly influences the conformational features of the linker. Specifically, α-mannose restricts the torsions of the IDP main chain more than other glycans whose equatorial 2-OH groups exhibit interactions that favor perpendicular glycan-protein backbone orientation. We suggest that IDP stiffening due to O-mannosylation impairs protease action, with contributions from protein-glycan interactions, protein flexibility, and protein stability. Our results further imply that resistance to proteolysis is an important driving force for evolutionary selection of α-mannose in eukaryotic IDPs, and more broadly, that glycan motifs for proteolysis protection likely coevolve with the protein sequence to which they attach.
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Affiliation(s)
- Erica T Prates
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80403 , USA .
- Institute of Chemistry , Center for Computational Engineering and Sciences , University of Campinas , 13084-862 , SP , Brazil
| | - Xiaoyang Guan
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Yaohao Li
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Xinfeng Wang
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Patrick K Chaffey
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Munir S Skaf
- Institute of Chemistry , Center for Computational Engineering and Sciences , University of Campinas , 13084-862 , SP , Brazil
| | - Michael F Crowley
- Biosciences Center , National Renewable Energy Laboratory , Golden , CO 80403 , USA .
| | - Zhongping Tan
- Department of Chemistry and Biochemistry and BioFrontiers Institute , University of Colorado , Boulder , CO 80303 , USA .
| | - Gregg T Beckham
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , CO 80403 , USA .
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12
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The PT/S-Box of Modular Cellulase AcCel12B Plays a Key Role in the Hydrolysis of Insoluble Cellulose. Catalysts 2018. [DOI: 10.3390/catal8030123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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13
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Distinct roles of N- and O-glycans in cellulase activity and stability. Proc Natl Acad Sci U S A 2017; 114:13667-13672. [PMID: 29229855 DOI: 10.1073/pnas.1714249114] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In nature, many microbes secrete mixtures of glycoside hydrolases, oxidoreductases, and accessory enzymes to deconstruct polysaccharides and lignin in plants. These enzymes are often decorated with N- and O-glycosylation, the roles of which have been broadly attributed to protection from proteolysis, as the extracellular milieu is an aggressive environment. Glycosylation has been shown to sometimes affect activity, but these effects are not fully understood. Here, we examine N- and O-glycosylation on a model, multimodular glycoside hydrolase family 7 cellobiohydrolase (Cel7A), which exhibits an O-glycosylated carbohydrate-binding module (CBM) and an O-glycosylated linker connected to an N- and O-glycosylated catalytic domain (CD)-a domain architecture common to many biomass-degrading enzymes. We report consensus maps for Cel7A glycosylation that include glycan sites and motifs. Additionally, we examine the roles of glycans on activity, substrate binding, and thermal and proteolytic stability. N-glycan knockouts on the CD demonstrate that N-glycosylation has little impact on cellulose conversion or binding, but does have major stability impacts. O-glycans on the CBM have little impact on binding, proteolysis, or activity in the whole-enzyme context. However, linker O-glycans greatly impact cellulose conversion via their contribution to proteolysis resistance. Molecular simulations predict an additional role for linker O-glycans, namely that they are responsible for maintaining separation between ordered domains when Cel7A is engaged on cellulose, as models predict α-helix formation and decreased cellulose interaction for the nonglycosylated linker. Overall, this study reveals key roles for N- and O-glycosylation that are likely broadly applicable to other plant cell-wall-degrading enzymes.
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14
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Keadtidumrongkul P, Suttangkakul A, Pinmanee P, Pattana K, Kittiwongwattana C, Apisitwanich S, Vuttipongchaikij S. Growth modulation effects of CBM2a under the control of AtEXP4 and CaMV35S promoters in Arabidopsis thaliana, Nicotiana tabacum and Eucalyptus camaldulensis. Transgenic Res 2017; 26:447-463. [PMID: 28349287 DOI: 10.1007/s11248-017-0015-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 03/21/2017] [Indexed: 11/29/2022]
Abstract
The expression of cell-wall-targeted Carbohydrate Binding Modules (CBMs) can alter cell wall properties and modulate growth and development in plants such as tobacco and potato. CBM2a identified in xylanase 10A from Cellulomonas fimi is of particular interest for its ability to bind crystalline cellulose. However, its potential for promoting plant growth has not been explored. In this work, we tested the ability of CBM2a to promote growth when expressed using both CaMV35S and a vascular tissue-specific promoter derived from Arabidopsis expansin4 (AtEXP4) in three plant species: Arabidopsis, Nicotiana tabacum and Eucalyptus camaldulensis. In Arabidopsis, the expression of AtEXP4pro:CBM2a showed trends for growth promoting effects including the increase of root and hypocotyl lengths and the enlargements of the vascular xylem area, fiber cells and vessel cells. However, in N. tabacum, the expression of CBM2a under the control of either CaMV35S or AtEXP4 promoter resulted in subtle changes in the plant growth, and the thickness of secondary xylem and vessel and fiber cell sizes were generally reduced in the transgenic lines with AtEXP4pro:CBM2a. In Eucalyptus, while transgenics expressing CaMV35S:CBM2a showed very subtle changes compared to wild type, those transgenics with AtEXP4pro:CBM2a showed increases in plant height, enlargement of xylem areas and xylem fiber and vessel cells. These data provide comparative effects of expressing CBM2a protein in different plant species, and this finding can be applied for plant biomass improvement.
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Affiliation(s)
- Pornthep Keadtidumrongkul
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
| | - Anongpat Suttangkakul
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
- Special Research Unit in Microalgal Molecular Genetics and Functional Genomics (MMGFG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
- Center of Advanced Studies for Tropical Natural Resources, Kasetsart University, 50 Ngam Wong Wan, Chatuchak, Bangkok, 10900, Thailand
| | - Phitsanu Pinmanee
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
| | - Kanokwan Pattana
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
| | - Chokchai Kittiwongwattana
- Department of Biology, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Chalongkrung Road, Ladkrabang, Bangkok, 10520, Thailand
| | - Somsak Apisitwanich
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
- Special Research Unit in Microalgal Molecular Genetics and Functional Genomics (MMGFG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
- Center of Advanced Studies for Tropical Natural Resources, Kasetsart University, 50 Ngam Wong Wan, Chatuchak, Bangkok, 10900, Thailand
- School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand
| | - Supachai Vuttipongchaikij
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand.
- Special Research Unit in Microalgal Molecular Genetics and Functional Genomics (MMGFG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand.
- Center of Advanced Studies for Tropical Natural Resources, Kasetsart University, 50 Ngam Wong Wan, Chatuchak, Bangkok, 10900, Thailand.
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15
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Carlin KB, Cruz-Teran CA, Kumar JP, Gomes C, Rao BM. Combinatorial Pairwise Assembly Efficiently Generates High Affinity Binders and Enables a "Mix-and-Read" Detection Scheme. ACS Synth Biol 2016; 5:1348-1354. [PMID: 27268028 DOI: 10.1021/acssynbio.6b00034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We show that a combinatorial library constructed by random pairwise assembly of low affinity binders can efficiently generate binders with increased affinity. Such a library based on the Sso7d scaffold, from a pool of low affinity binders subjected to random mutagenesis, contained putative high affinity clones for a model target (lysozyme) at higher frequency than a library of monovalent mutants generated by random mutagenesis alone. Increased binding affinity was due to intramolecular avidity generated by linking binders targeting nonoverlapping epitopes; individual binders of KD ∼ 1.3 μM and 250 nM produced a bivalent binder with apparent KD ∼ 2 nM. Furthermore, the bivalent protein retained thermal stability (TM = 84.5 °C) and high recombinant expression yields in E. coli. Finally, when binders comprising the bivalent protein are fused to two of the three fragments of tripartite split-green fluorescent protein (GFP), target-dependent reconstitution of fluorescence occurs, thereby enabling a "mix-and-read" assay for target quantification.
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Affiliation(s)
- Kevin B. Carlin
- Department of Chemical
and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Carlos A. Cruz-Teran
- Department of Chemical
and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jay Prakash Kumar
- Institute of Stem Cell Biology and Regenerative Medicine, NCBS-TIFR, Bangalore 560065, Karnataka, India
- School of Chemical & Biotechnology, SASTRA University, Thanjavur 613401, Tamil Nadu, India
| | - Catherina Gomes
- Department of Chemical
and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Balaji M. Rao
- Department of Chemical
and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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16
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Characterization of a Cellulomonas fimi exoglucanase/xylanase-endoglucanase gene fusion which improves microbial degradation of cellulosic biomass. Enzyme Microb Technol 2016; 93-94:113-121. [DOI: 10.1016/j.enzmictec.2016.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 11/17/2022]
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17
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Labourel A, Crouch LI, Brás JLA, Jackson A, Rogowski A, Gray J, Yadav MP, Henrissat B, Fontes CMGA, Gilbert HJ, Najmudin S, Baslé A, Cuskin F. The Mechanism by Which Arabinoxylanases Can Recognize Highly Decorated Xylans. J Biol Chem 2016; 291:22149-22159. [PMID: 27531750 PMCID: PMC5063996 DOI: 10.1074/jbc.m116.743948] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Indexed: 12/15/2022] Open
Abstract
The enzymatic degradation of plant cell walls is an important biological process of increasing environmental and industrial significance. Xylan, a major component of the plant cell wall, consists of a backbone of β-1,4-xylose (Xylp) units that are often decorated with arabinofuranose (Araf) side chains. A large penta-modular enzyme, CtXyl5A, was shown previously to specifically target arabinoxylans. The mechanism of substrate recognition displayed by the enzyme, however, remains unclear. Here we report the crystal structure of the arabinoxylanase and the enzyme in complex with ligands. The data showed that four of the protein modules adopt a rigid structure, which stabilizes the catalytic domain. The C-terminal non-catalytic carbohydrate binding module could not be observed in the crystal structure, suggesting positional flexibility. The structure of the enzyme in complex with Xylp-β-1,4-Xylp-β-1,4-Xylp-[α-1,3-Araf]-β-1,4-Xylp showed that the Araf decoration linked O3 to the xylose in the active site is located in the pocket (−2* subsite) that abuts onto the catalytic center. The −2* subsite can also bind to Xylp and Arap, explaining why the enzyme can utilize xylose and arabinose as specificity determinants. Alanine substitution of Glu68, Tyr92, or Asn139, which interact with arabinose and xylose side chains at the −2* subsite, abrogates catalytic activity. Distal to the active site, the xylan backbone makes limited apolar contacts with the enzyme, and the hydroxyls are solvent-exposed. This explains why CtXyl5A is capable of hydrolyzing xylans that are extensively decorated and that are recalcitrant to classic endo-xylanase attack.
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Affiliation(s)
- Aurore Labourel
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Lucy I Crouch
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Joana L A Brás
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal, NZYTech Genes & Enzymes, 1649-038 Lisboa, Portugal
| | - Adam Jackson
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Artur Rogowski
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Joseph Gray
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Madhav P Yadav
- the Eastern Regional Research Center, United States Department of Agriculture-Agricultural Research Service, Wyndmoor, Pennsylvania 19038
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, UMR7857 CNRS, Aix-Marseille University, F-13288 Marseille, France, USC1408 Architecture et Fonction des Macromolécules Biologiques, INRA, F-13288 Marseille, France, and the Department of Biological Sciences, King Abdulaziz University, Jedda 21589, Saudi Arabia
| | - Carlos M G A Fontes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal, NZYTech Genes & Enzymes, 1649-038 Lisboa, Portugal
| | - Harry J Gilbert
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Shabir Najmudin
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal,
| | - Arnaud Baslé
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom,
| | - Fiona Cuskin
- From the Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom,
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18
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Wei G, Xi W, Nussinov R, Ma B. Protein Ensembles: How Does Nature Harness Thermodynamic Fluctuations for Life? The Diverse Functional Roles of Conformational Ensembles in the Cell. Chem Rev 2016; 116:6516-51. [PMID: 26807783 PMCID: PMC6407618 DOI: 10.1021/acs.chemrev.5b00562] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
All soluble proteins populate conformational ensembles that together constitute the native state. Their fluctuations in water are intrinsic thermodynamic phenomena, and the distributions of the states on the energy landscape are determined by statistical thermodynamics; however, they are optimized to perform their biological functions. In this review we briefly describe advances in free energy landscape studies of protein conformational ensembles. Experimental (nuclear magnetic resonance, small-angle X-ray scattering, single-molecule spectroscopy, and cryo-electron microscopy) and computational (replica-exchange molecular dynamics, metadynamics, and Markov state models) approaches have made great progress in recent years. These address the challenging characterization of the highly flexible and heterogeneous protein ensembles. We focus on structural aspects of protein conformational distributions, from collective motions of single- and multi-domain proteins, intrinsically disordered proteins, to multiprotein complexes. Importantly, we highlight recent studies that illustrate functional adjustment of protein conformational ensembles in the crowded cellular environment. We center on the role of the ensemble in recognition of small- and macro-molecules (protein and RNA/DNA) and emphasize emerging concepts of protein dynamics in enzyme catalysis. Overall, protein ensembles link fundamental physicochemical principles and protein behavior and the cellular network and its regulation.
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Affiliation(s)
- Guanghong Wei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China
| | - Wenhui Xi
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Sciences (MOE), and Department of Physics, Fudan University, Shanghai, P. R. China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
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19
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Extending the linker region increases the activity of the Bacillus subtilis cellulase CelI15. Biotechnol Lett 2016; 38:1587-93. [PMID: 27271520 DOI: 10.1007/s10529-016-2136-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022]
Abstract
OBJECTIVES To investigate the effect of the linker region (LR) on the enzymatic activity, stability, and flexibility of Bacillus subtilis cellulase CelI15, six mutants were constructed that contained increasing numbers of the LR. RESULTS The CelI15 mutant with three copies of the LR (approx. 57 amino acids) showed the highest activity, which was almost 20 % greater than that of wild type CelI15. The stability of the mutant enzymes increased as the copy number of the LR decreased. However, the substrate affinity of the mutant enzymes increased as the LR copy number increased, and the mutant with four copies of the LR exhibited the highest substrate affinity. Additionally, the flexibility of the CelI15 mutants increased as the LR copy number increased from zero to four copies, although it decreased sharply for the mutant with five copies of the LR. CONCLUSION The activity of CelI15 was increased by increasing the LR copy number, which could be a potential way to improve its enzymatic properties.
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20
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Kopka B, Diener M, Wirtz A, Pohl M, Jaeger KE, Krauss U. Purification and simultaneous immobilization of Arabidopsis thaliana hydroxynitrile lyase using a family 2 carbohydrate-binding module. Biotechnol J 2015; 10:811-9. [PMID: 25755120 DOI: 10.1002/biot.201400786] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/13/2015] [Accepted: 03/04/2015] [Indexed: 11/12/2022]
Abstract
Tedious, time- and labor-intensive protein purification and immobilization procedures still represent a major bottleneck limiting the widespread application of enzymes in synthetic chemistry and industry. We here exemplify a simple strategy for the direct site-specific immobilization of proteins from crude cell extracts by fusion of a family 2 carbohydrate-binding module (CBM) derived from the exoglucanase/xylanase Cex from Cellulomonas fimi to a target enzyme. By employing a tripartite fusion protein consisting of the CBM, a flavin-based fluorescent protein (FbFP), and the Arabidopsis thaliana hydroxynitrile lyase (AtHNL), binding to cellulosic carrier materials can easily be monitored via FbFP fluorescence. Adsorption properties (kinetics and quantities) were studied for commercially available Avicel PH-101 and regenerated amorphous cellulose (RAC) derived from Avicel. The resulting immobilizates showed similar activities as the wild-type enzyme but displayed increased stability in the weakly acidic pH range. Finally, Avicel, RAC and cellulose acetate (CA) preparations were used for the synthesis of (R)-mandelonitrile in micro-aqueous methyl tert-butyl ether (MTBE) demonstrating the applicability and stability of the immobilizates for biotransformations in both aqueous and organic reaction systems.
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Affiliation(s)
- Benita Kopka
- Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
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21
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Payne CM, Knott BC, Mayes HB, Hansson H, Himmel ME, Sandgren M, Ståhlberg J, Beckham GT. Fungal Cellulases. Chem Rev 2015; 115:1308-448. [DOI: 10.1021/cr500351c] [Citation(s) in RCA: 533] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506, United States
| | - Brandon C. Knott
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
| | - Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henrik Hansson
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Mats Sandgren
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
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22
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Greene ER, Himmel ME, Beckham GT, Tan Z. Glycosylation of Cellulases: Engineering Better Enzymes for Biofuels. Adv Carbohydr Chem Biochem 2015; 72:63-112. [PMID: 26613815 DOI: 10.1016/bs.accb.2015.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cellulose in plant cell walls is the largest reservoir of renewable carbon on Earth. The saccharification of cellulose from plant biomass into soluble sugars can be achieved using fungal and bacterial cellulolytic enzymes, cellulases, and further converted into fuels and chemicals. Most fungal cellulases are both N- and O-glycosylated in their native form, yet the consequences of glycosylation on activity and structure are not fully understood. Studying protein glycosylation is challenging as glycans are extremely heterogeneous, stereochemically complex, and glycosylation is not under direct genetic control. Despite these limitations, many studies have begun to unveil the role of cellulase glycosylation, especially in the industrially relevant cellobiohydrolase from Trichoderma reesei, Cel7A. Glycosylation confers many beneficial properties to cellulases including enhanced activity, thermal and proteolytic stability, and structural stabilization. However, glycosylation must be controlled carefully as such positive effects can be dampened or reversed. Encouragingly, methods for the manipulation of glycan structures have been recently reported that employ genetic tuning of glycan-active enzymes expressed from homogeneous and heterologous fungal hosts. Taken together, these studies have enabled new strategies for the exploitation of protein glycosylation for the production of enhanced cellulases for biofuel production.
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23
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van Zyl LJ, Schubert WD, Tuffin MI, Cowan DA. Structure and functional characterization of pyruvate decarboxylase from Gluconacetobacter diazotrophicus. BMC STRUCTURAL BIOLOGY 2014; 14:21. [PMID: 25369873 PMCID: PMC4428508 DOI: 10.1186/s12900-014-0021-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/25/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND Bacterial pyruvate decarboxylases (PDC) are rare. Their role in ethanol production and in bacterially mediated ethanologenic processes has, however, ensured a continued and growing interest. PDCs from Zymomonas mobilis (ZmPDC), Zymobacter palmae (ZpPDC) and Sarcina ventriculi (SvPDC) have been characterized and ZmPDC has been produced successfully in a range of heterologous hosts. PDCs from the Acetobacteraceae and their role in metabolism have not been characterized to the same extent. Examples include Gluconobacter oxydans (GoPDC), G. diazotrophicus (GdPDC) and Acetobacter pasteutrianus (ApPDC). All of these organisms are of commercial importance. RESULTS This study reports the kinetic characterization and the crystal structure of a PDC from Gluconacetobacter diazotrophicus (GdPDC). Enzyme kinetic analysis indicates a high affinity for pyruvate (K M 0.06 mM at pH 5), high catalytic efficiencies (1.3 • 10(6) M(-1) • s(-1) at pH 5), pHopt of 5.5 and Topt at 45°C. The enzyme is not thermostable (T½ of 18 minutes at 60°C) and the calculated number of bonds between monomers and dimers do not give clear indications for the relatively lower thermostability compared to other PDCs. The structure is highly similar to those described for Z. mobilis (ZmPDC) and A. pasteurianus PDC (ApPDC) with a rmsd value of 0.57 Å for Cα when comparing GdPDC to that of ApPDC. Indole-3-pyruvate does not serve as a substrate for the enzyme. Structural differences occur in two loci, involving the regions Thr341 to Thr352 and Asn499 to Asp503. CONCLUSIONS This is the first study of the PDC from G. diazotrophicus (PAL5) and lays the groundwork for future research into its role in this endosymbiont. The crystal structure of GdPDC indicates the enzyme to be evolutionarily closely related to homologues from Z. mobilis and A. pasteurianus and suggests strong selective pressure to keep the enzyme characteristics in a narrow range. The pH optimum together with reduced thermostability likely reflect the host organisms niche and conditions under which these properties have been naturally selected for. The lack of activity on indole-3-pyruvate excludes this decarboxylase as the enzyme responsible for indole acetic acid production in G. diazotrophicus.
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Affiliation(s)
- Leonardo J van Zyl
- Institute for Microbial Biotechnology and Metagenomics (IMBM), University of the Western Cape, Robert Sobukwe Road, Bellville, Cape Town, South Africa.
| | - Wolf-Dieter Schubert
- Department of Biochemistry, University of Pretoria, 2 Lynnwood Road, Pretoria, 0002, South Africa.
| | - Marla I Tuffin
- Institute for Microbial Biotechnology and Metagenomics (IMBM), University of the Western Cape, Robert Sobukwe Road, Bellville, Cape Town, South Africa.
| | - Don A Cowan
- Department of Genetics, University of Pretoria, Pretoria, 0002, South Africa.
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24
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Ferella L, Luchinat C, Ravera E, Rosato A. SedNMR: a web tool for optimizing sedimentation of macromolecular solutes for SSNMR. JOURNAL OF BIOMOLECULAR NMR 2013; 57:319-26. [PMID: 24243317 DOI: 10.1007/s10858-013-9795-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 11/11/2013] [Indexed: 05/09/2023]
Abstract
We have proposed solid state NMR (SSNMR) of sedimented solutes as a novel approach to sample preparation for biomolecular SSNMR without crystallization or other sample manipulations. The biomolecules are confined by high gravity--obtained by centrifugal forces either directly in a SSNMR rotor or in a ultracentrifugal device--into a hydrated non-crystalline solid suitable for SSNMR investigations. When gravity is removed, the sample reverts to solution and can be treated as any solution NMR sample. We here describe a simple web tool to calculate the relevant parameters for the success of the experiment.
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Affiliation(s)
- Lucio Ferella
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, FI, Italy
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25
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Vidangos N, Maris AE, Young A, Hong E, Pelton JG, Batchelor JD, Wemmer DE. Structure, function, and tethering of DNA-binding domains in σ⁵⁴ transcriptional activators. Biopolymers 2013; 99:1082-96. [PMID: 23818155 PMCID: PMC3932985 DOI: 10.1002/bip.22333] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 11/07/2022]
Abstract
We compare the structure, activity, and linkage of DNA-binding domains (DBDs) from σ(54) transcriptional activators and discuss how the properties of the DBDs and the linker to the neighboring domain are affected by the overall properties and requirements of the full proteins. These transcriptional activators bind upstream of specific promoters that utilize σ(54)-polymerase. Upon receiving a signal the activators assemble into hexamers, which then, through adenosine triphosphate (ATP) hydrolysis, drive a conformational change in polymerase that enables transcription initiation. We present structures of the DBDs of activators nitrogen regulatory protein C 1 (NtrC1) and Nif-like homolog 2 (Nlh2) from the thermophile Aquifex aeolicus. The structures of these domains and their relationship to other parts of the activators are discussed. These structures are compared with previously determined structures of the DBDs of NtrC4, NtrC, ZraR, and factor for inversion stimulation. The N-terminal linkers that connect the DBDs to the central domains in NtrC1 and Nlh2 were studied and found to be unstructured. Additionally, a crystal structure of full-length NtrC1 was solved, but density of the DBDs was extremely weak, further indicating that the linker between ATPase and DBDs functions as a flexible tether. Flexible linking of ATPase and DBDs is likely necessary to allow assembly of the active hexameric ATPase ring. The comparison of this set of activators also shows clearly that strong dimerization of the DBD only occurs when other domains do not dimerize strongly.
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Affiliation(s)
- Natasha Vidangos
- Department of Chemistry and QB3 Institute, University of California, Berkeley, CA, 94720-1460
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Kamat RK, Ma W, Yang Y, Zhang Y, Wang C, Kumar CV, Lin Y. Adsorption and hydrolytic activity of the polycatalytic cellulase nanocomplex on cellulose. ACS APPLIED MATERIALS & INTERFACES 2013; 5:8486-8494. [PMID: 23968137 DOI: 10.1021/am401916k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The formation of polycatalytic enzyme complexes may enhance the effectiveness of enzymes due to improved substrate interaction and synergistic actions of multiple enzymes in proximity. Much effort has been made to develop highly efficient polycatalytic cellulase complexes by immobilizing cellulases on low-cost polymer or nanoparticle scaffolds, aiming at their potential applications in biomass conversion to fuels. However, some key cellulases carry out the hydrolytic reaction on crystalline cellulose in a directional, processive manner. A large, artificial polycatalytic complex is unlikely to undergo a highly coordinated motion to slide on the cellulose surface as a whole unit. The mechanism underlying the activity enhancements observed in some artificial cellulase complexes and the limit of this approach remain elusive. Herein, we report the synthesis of polycatalytic cellulase complexes bound to colloidal polymer nanoparticles with a magnetic core and describe their unique adsorption, hydrolytic activities, and motions on cellulose. The polycatalytic clusters of cellulases on colloidal polymers show an increased rate of hydrolytic reactions on cellulose, but this was observed mainly at relatively low cellulase-to-cellulose ratios. Enhanced efficiency is mainly attributed to increased local concentrations of cellulases on the scaffolds and their polyvalent interactions with cellulose. However, once bound, the polycatalytic complexes can only carry out reactions locally and are not capable of relocating to new sites rapidly due to their lack of long-range surface mobility and their extremely tight binding. The development of highly optimized polycatalytic complexes may arise by developing novel nanoscaffolds that induce concerted motion of the complex as a whole.
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Affiliation(s)
- Ranjan K Kamat
- Polymer Program, Institute of Material Science, §Department of Chemistry, and ∥Department of Molecular and Cellular Biology, University of Connecticut , Storrs, Connecticut 06269, United States
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Payne CM, Resch MG, Chen L, Crowley MF, Himmel ME, Taylor LE, Sandgren M, Ståhlberg J, Stals I, Tan Z, Beckham GT. Glycosylated linkers in multimodular lignocellulose-degrading enzymes dynamically bind to cellulose. Proc Natl Acad Sci U S A 2013; 110:14646-51. [PMID: 23959893 PMCID: PMC3767562 DOI: 10.1073/pnas.1309106110] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plant cell-wall polysaccharides represent a vast source of food in nature. To depolymerize polysaccharides to soluble sugars, many organisms use multifunctional enzyme mixtures consisting of glycoside hydrolases, lytic polysaccharide mono-oxygenases, polysaccharide lyases, and carbohydrate esterases, as well as accessory, redox-active enzymes for lignin depolymerization. Many of these enzymes that degrade lignocellulose are multimodular with carbohydrate-binding modules (CBMs) and catalytic domains connected by flexible, glycosylated linkers. These linkers have long been thought to simply serve as a tether between structured domains or to act in an inchworm-like fashion during catalytic action. To examine linker function, we performed molecular dynamics (MD) simulations of the Trichoderma reesei Family 6 and Family 7 cellobiohydrolases (TrCel6A and TrCel7A, respectively) bound to cellulose. During these simulations, the glycosylated linkers bind directly to cellulose, suggesting a previously unknown role in enzyme action. The prediction from the MD simulations was examined experimentally by measuring the binding affinity of the Cel7A CBM and the natively glycosylated Cel7A CBM-linker. On crystalline cellulose, the glycosylated linker enhances the binding affinity over the CBM alone by an order of magnitude. The MD simulations before and after binding of the linker also suggest that the bound linker may affect enzyme action due to significant damping in the enzyme fluctuations. Together, these results suggest that glycosylated linkers in carbohydrate-active enzymes, which are intrinsically disordered proteins in solution, aid in dynamic binding during the enzymatic deconstruction of plant cell walls.
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Affiliation(s)
- Christina M. Payne
- Biosciences Center and
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506
| | | | - Liqun Chen
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | | | | | | | - Mats Sandgren
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Ingeborg Stals
- Faculty of Applied Bioscience Engineering, University College Ghent, 9000 Ghent, Belgium
- Department of Biochemistry and Molecular Biology, Ghent University, 9000 Ghent, Belgium; and
| | - Zhongping Tan
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | - Gregg T. Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401
- Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401
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Yaniv O, Morag E, Borovok I, Bayer EA, Lamed R, Frolow F, Shimon LJW. Structure of a family 3a carbohydrate-binding module from the cellulosomal scaffoldin CipA of Clostridium thermocellum with flanking linkers: implications for cellulosome structure. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:733-7. [PMID: 23832198 PMCID: PMC3702315 DOI: 10.1107/s174430911301614x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 06/10/2013] [Indexed: 11/10/2022]
Abstract
The cellulosome of the cellulolytic bacterium Clostridium thermocellum has a structural multi-modular protein called CipA (cellulosome-integrating protein A) that includes nine enzyme-binding cohesin modules and a family 3 cellulose-binding module (CBM3a). In the CipA protein, the CBM3a module is located between the second and third cohesin modules and is connected to them via proline/threonine-rich linkers. The structure of CBM3a with portions of the C- and N-terminal flanking linker regions, CBM3a-L, has been determined to a resolution of 1.98 Å. The structure is a β-sandwich with a structural Ca(2+) ion. The structure is consistent with the previously determined CipA CBM structure; however, the structured linker regions provide a deeper insight into the overall cellulosome structure and assembly.
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Affiliation(s)
- Oren Yaniv
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
- The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ely Morag
- Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
- The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Edward A. Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
- The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Felix Frolow
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
- The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Linda J. W. Shimon
- Department of Chemical Research Support, The Weizmann Institute of Science, 76100 Rehovot, Israel
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Lu X, Liu S, Feng Y, Rao S, Zhou X, Wang M, Du G, Chen J. Enhanced thermal stability of Pseudomonas aeruginosa lipoxygenase through modification of two highly flexible regions. Appl Microbiol Biotechnol 2013; 98:1663-9. [DOI: 10.1007/s00253-013-5039-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/06/2013] [Accepted: 06/06/2013] [Indexed: 01/20/2023]
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Lobo MDP, Silva FDA, Landim PGDC, da Cruz PR, de Brito TL, de Medeiros SC, Oliveira JTA, Vasconcelos IM, Pereira HD, Grangeiro TB. Expression and efficient secretion of a functional chitinase from Chromobacterium violaceum in Escherichia coli. BMC Biotechnol 2013; 13:46. [PMID: 23725035 PMCID: PMC3701571 DOI: 10.1186/1472-6750-13-46] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 05/17/2013] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Chromobacterium violaceum is a free-living β-proteobacterium found in tropical and subtropical regions. The genomic sequencing of C. violaceum ATCC 12472 has revealed many genes that underpin its adaptability to diverse ecosystems. Moreover, C. violaceum genes with potential applications in industry, medicine and agriculture have also been identified, such as those encoding chitinases. However, none of the chitinase genes of the ATCC 12472 strain have been subjected to experimental validation. Chitinases (EC 3.2.1.14) hydrolyze the β-(1,4) linkages in chitin, an abundant biopolymer found in arthropods, mollusks and fungi. These enzymes are of great biotechnological interest as potential biocontrol agents against pests and pathogens. This work aimed to experimentally validate one of the chitinases from C. violaceum. RESULTS The open reading frame (ORF) CV2935 of C. violaceum ATCC 12472 encodes a protein (439 residues) that is composed of a signal peptide, a chitin-binding domain, a linker region, and a C-terminal catalytic domain belonging to family 18 of the glycoside hydrolases. The ORF was amplified by PCR and cloned into the expression vector pET303/CT-His. High levels of chitinolytic activity were detected in the cell-free culture supernatant of E. coli BL21(DE3) cells harboring the recombinant plasmid and induced with IPTG. The secreted recombinant protein was purified by affinity chromatography on a chitin matrix and showed an apparent molecular mass of 43.8 kDa, as estimated by denaturing polyacrylamide gel electrophoresis. N-terminal sequencing confirmed the proper removal of the native signal peptide during the secretion of the recombinant product. The enzyme was able to hydrolyze colloidal chitin and the synthetic substrates p-nitrophenyl-β-D-N,N'-diacetylchitobiose and p-nitrophenyl-β-D-N,N',N"-triacetylchitotriose. The optimum pH for its activity was 5.0, and the enzyme retained ~32% of its activity when heated to 60°C for 30 min. CONCLUSIONS A C. violaceum chitinase was expressed in E. coli and purified by affinity chromatography on a chitin matrix. The secretion of the recombinant protein into the culture medium was directed by its native signal peptide. The mature enzyme was able to hydrolyze colloidal chitin and synthetic substrates. This newly identified signal peptide is a promising secretion factor that should be further investigated in future studies, aiming to demonstrate its usefulness as an alternative tool for the extracellular production of recombinant proteins in E. coli.
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Affiliation(s)
- Marina Duarte Pinto Lobo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, CE CEP 60.455-970, Brazil
| | - Fredy Davi Albuquerque Silva
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, CE CEP 60.455-970, Brazil
| | | | | | - Thaís Lima de Brito
- Departamento de Biologia, UFC, Laboratório de Genética Molecular, Fortaleza, CE, Brazil
| | | | - José Tadeu Abreu Oliveira
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, CE CEP 60.455-970, Brazil
| | - Ilka Maria Vasconcelos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, CE CEP 60.455-970, Brazil
| | - Humberto D’Muniz Pereira
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense, 400, São Carlos, SP CEP 13.566-590, Brazil
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31
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A single-molecule analysis reveals morphological targets for cellulase synergy. Nat Chem Biol 2013; 9:356-61. [DOI: 10.1038/nchembio.1227] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 02/28/2013] [Indexed: 11/08/2022]
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Bertini I, Engelke F, Gonnelli L, Knott B, Luchinat C, Osen D, Ravera E. On the use of ultracentrifugal devices for sedimented solute NMR. JOURNAL OF BIOMOLECULAR NMR 2012; 54:123-7. [PMID: 22872367 DOI: 10.1007/s10858-012-9657-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/26/2012] [Indexed: 05/09/2023]
Abstract
We have recently proposed sedimented solute NMR (SedNMR) as a solid-state method to access biomolecules without the need of crystallization or other sample manipulation. The drawback of SedNMR is that samples are intrinsically diluted and this is detrimental for the signal intensity. Ultracentrifugal devices can be used to increase the amount of sample inside the rotor, overcoming the intrinsic sensitivity limitation of the method. We designed two different devices and we here report the directions for using such devices and the relevant equations for determining the parameters for sedimentation.
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Affiliation(s)
- Ivano Bertini
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, FI, Italy.
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Yuwen T, Post CB, Skrynnikov N. Domain cooperativity in multidomain proteins: what can we learn from molecular alignment in anisotropic media? JOURNAL OF BIOMOLECULAR NMR 2011; 51:131-50. [PMID: 21947922 PMCID: PMC4721247 DOI: 10.1007/s10858-011-9548-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 07/07/2011] [Indexed: 05/13/2023]
Abstract
Many proteins have modular design with multiple globular domains connected via flexible linkers. As a simple model of such system, we study a tandem construct consisting of two identical SH3 domains and a variable-length Gly/Ser linker. When the linker is short, this construct represents a dumbbell-shaped molecule with limited amount of domain-domain mobility. Due to its elongated shape, this molecule efficiently aligns in steric alignment media. As the length of the linker increases, the two domains become effectively uncoupled and begin to behave as independent entities. Consequently, their degree of alignment drops, approaching that found in the (near-spherical) isolated SH3 domains. To model the dependence of alignment parameters on the length of the interdomain linker, we have generated in silico a series of conformational ensembles representing SH3 tandems with different linker length. These ensembles were subsequently used as input for alignment prediction software PALES. The predicted alignment tensors were compared with the results of experimental measurements using a series of tandem-SH3 samples in PEG/hexanol alignment media. This comparison broadly confirmed the expected trends. At the same time, it has been found that the isolated SH3 domain aligns much stronger than expected. This finding can be attributed to complex morphology of the PEG/hexanol media and/or to weak site-specific interactions between the protein and the media. In the latter case, there are strong indications that electrostatic interactions may play a role. The fact that PEG/hexanol does not behave as a simple steric media should serve as a caution for studies that use PALES as a quantitative prediction tool (especially for disordered proteins). Further progress in this area depends on our ability to accurately model the anisotropic media and its site-specific interactions with protein molecules. Once this ability is improved, it should be possible to use the alignment parameters as a measure of domain-domain cooperativity, thus identifying the situations where two domains transiently interact with each other or become coupled through a partially structured linker.
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Affiliation(s)
- Tairan Yuwen
- Department of Chemistry, Purdue University, West Lafayette IN 47907, USA
| | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette IN 47907, USA
| | - Nikolai Skrynnikov
- Department of Chemistry, Purdue University, West Lafayette IN 47907, USA
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Beckham GT, Bomble YJ, Matthews JF, Taylor CB, Resch MG, Yarbrough JM, Decker SR, Bu L, Zhao X, McCabe C, Wohlert J, Bergenstråhle M, Brady JW, Adney WS, Himmel ME, Crowley MF. The O-glycosylated linker from the Trichoderma reesei Family 7 cellulase is a flexible, disordered protein. Biophys J 2011; 99:3773-81. [PMID: 21112302 DOI: 10.1016/j.bpj.2010.10.032] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 10/19/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022] Open
Abstract
Fungi and bacteria secrete glycoprotein cocktails to deconstruct cellulose. Cellulose-degrading enzymes (cellulases) are often modular, with catalytic domains for cellulose hydrolysis and carbohydrate-binding modules connected by linkers rich in serine and threonine with O-glycosylation. Few studies have probed the role that the linker and O-glycans play in catalysis. Since different expression and growth conditions produce different glycosylation patterns that affect enzyme activity, the structure-function relationships that glycosylation imparts to linkers are relevant for understanding cellulase mechanisms. Here, the linker of the Trichoderma reesei Family 7 cellobiohydrolase (Cel7A) is examined by simulation. Our results suggest that the Cel7A linker is an intrinsically disordered protein with and without glycosylation. Contrary to the predominant view, the O-glycosylation does not change the stiffness of the linker, as measured by the relative fluctuations in the end-to-end distance; rather, it provides a 16 Å extension, thus expanding the operating range of Cel7A. We explain observations from previous biochemical experiments in the light of results obtained here, and compare the Cel7A linker with linkers from other cellulases with sequence-based tools to predict disorder. This preliminary screen indicates that linkers from Family 7 enzymes from other genera and other cellulases within T. reesei may not be as disordered, warranting further study.
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Affiliation(s)
- Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado, USA
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Adams JJ, Currie MA, Ali S, Bayer EA, Jia Z, Smith SP. Insights into higher-order organization of the cellulosome revealed by a dissect-and-build approach: crystal structure of interacting Clostridium thermocellum multimodular components. J Mol Biol 2010; 396:833-9. [PMID: 20070943 DOI: 10.1016/j.jmb.2010.01.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 01/05/2010] [Accepted: 01/06/2010] [Indexed: 10/20/2022]
Abstract
Cellulosomes are large, multienzyme, plant cell wall-degrading protein complexes found affixed to the surface of a variety of anaerobic microbes. The core of the cellulosome is a noncatalytic scaffoldin protein, which contains several type-I cohesin modules that bind type-I dockerin-containing enzymatic subunits, a cellulose-binding module, an X module, and a type-II dockerin that interacts with type-II cohesin-containing cell surface proteins. The unique arrangement of the enzymatic subunits in the cellulosome complex, made possible by the scaffoldin subunit, promotes enhanced substrate degradation relative to the enzymes free in solution. Despite representative high-resolution structures of all of the individual modules of the cellulosome, this mechanism of enzymatic synergy remains poorly understood. Consequently, a model of the entire cellulosome and a detailed picture of intermodular contacts will provide more detailed insight into cellulosome activity. Toward this goal, we have solved the structure of a multimodular heterodimeric complex from Clostridium thermocellum composed of the type-II cohesin module of the cell surface protein SdbA bound to a trimodular C-terminal fragment of the scaffoldin subunit CipA to a resolution of 1.95 A. The linker that connects the ninth type-I cohesin module and the X module has elevated temperature factors, reflecting an inherent flexibility within this region. Interestingly, a novel dimer interface was observed between CipA and a second, symmetry-related CipA molecule within the crystal structure, mediated by contacts between a type-I cohesin and an X module of a symmetry mate, resulting in two intertwined scaffoldins. Sedimentation velocity experiments confirmed that dimerization also occurs in solution. These observations support the intriguing possibility that individual cellulosomes can associate with one another via inter-scaffoldin interactions, which may play a role in the mechanism of action of the complex.
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Affiliation(s)
- Jarrett J Adams
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
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Matamá T, Araújo R, Gübitz GM, Casal M, Cavaco-Paulo A. Functionalization of cellulose acetate fibers with engineered cutinases. Biotechnol Prog 2009; 26:636-43. [DOI: 10.1002/btpr.364] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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39
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Noach I, Frolow F, Alber O, Lamed R, Shimon LJW, Bayer EA. Intermodular linker flexibility revealed from crystal structures of adjacent cellulosomal cohesins of Acetivibrio cellulolyticus. J Mol Biol 2009; 391:86-97. [PMID: 19501595 DOI: 10.1016/j.jmb.2009.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/25/2009] [Accepted: 06/02/2009] [Indexed: 10/20/2022]
Abstract
Cellulosome complexes comprise an intercalated set of multimodular dockerin-containing enzymatic subunits connected to cohesin-containing nonenzymatic subunits called scaffoldins. The adjoining modules in each cellulosomal subunit are interconnected by a variety of linker segments of different lengths and composition. The exact role of the cellulosomal linkers has yet to be described, although it is assumed that they contribute to the architecture and action of the cellulosome by providing the protein subunits with flexibility and by providing spacers between the enzymatic modules that could enhance interactions with the cellulose substrate. Here we present four crystal structures of Acetivibrio cellulolyticus cellulosomal type II cohesins with linker extensions. Two of the structures represent two different crystal forms (trigonal and orthorhombic) of the same N-terminal cohesin module (CohB1) together with its full (6-residue) native C-terminal linker, derived from scaffoldin B. The other two structures belong to the adjacent (second) cohesin module (CohB2), each of which was crystallized with the same 6-residue linker segment, but now positioned at the N-terminus and with either a truncated (5-residue) or a full-length (45-residue) C-terminal linker, respectively. Comparison between the two CohB1 structures revealed significant differences in the conformation of their equivalent C-terminal linker segment. In one crystal form a helical conformation was observed, as opposed to an extended conformation in the other. The CohB2 structures also displayed diverse conformations in their linker segments. In these structures, different linker conformations were observed in the individual molecules within the asymmetric unit of each structure. This conformational diversity implies that the linkers may adopt alternative conformations in their natural environment, consistent with varying environmental conditions. The findings suggest that linkers can play an important role in the assembly, dynamics and function of the cellulosomal components.
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Affiliation(s)
- Ilit Noach
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
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40
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Abstract
We develop a mechanochemical model for the dynamics of cellulase, a two-domain enzyme connected by a peptide linker, as it extracts and hydrolyzes a cellulose polymer from a crystalline substrate. We consider two random walkers, representing the catalytic domain (CD) and the carbohydrate binding module (CBM), whose rates for stepping are biased by the coupling through the linker and the energy required to lift the cellulose polymer from the crystalline surface. Our results show that the linker length and stiffness play a critical role in the cooperative action of the CD and CBM domains and that, for a given linker length, the steady-state hydrolysis shows a maximum at some intermediate linker stiffness. The maximum hydrolysis rate corresponds to a transition of the linker from a compressed to an extended conformation, where the system exhibits maximum fluctuation, as measured by the variance of the separation distance between the two domains and the dispersion around the mean hydrolysis speed. In the range of experimentally known values of the parameters of our model, improving the intrinsic hydrolytic activity of the CD leads to a proportional increase in the overall hydrolysis rate.
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Affiliation(s)
- Christina L. Ting
- Biochemistry and Molecular Biophysics, California Institute of Technology, Pasadena, CA 91125
| | - Dmitrii E. Makarov
- Department of Chemistry and Biochemistry and Institute for Theoretical Chemistry, University of Texas at Austin, Austin, Texas, 78712
| | - Zhen-Gang Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
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41
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Bertini I, Kursula P, Luchinat C, Parigi G, Vahokoski J, Wilmanns M, Yuan J. Accurate Solution Structures of Proteins from X-ray Data and a Minimal Set of NMR Data: Calmodulin−Peptide Complexes As Examples. J Am Chem Soc 2009; 131:5134-44. [DOI: 10.1021/ja8080764] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
| | - Petri Kursula
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
| | - Juha Vahokoski
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
| | - Matthias Wilmanns
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
| | - Jing Yuan
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, EMBL-Hamburg c/o DESY, Hamburg, Germany, Department of Biochemistry, University of Oulu, Oulu, Finland, and Department of Agricultural Biotechnology, University of Florence, via Maragliano 75-77, 50144 Florence, Italy
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42
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Cloning of a rumen fungal xylanase gene and purification of the recombinant enzyme via artificial oil bodies. Appl Microbiol Biotechnol 2008; 79:225-33. [PMID: 18415096 DOI: 10.1007/s00253-008-1418-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 02/14/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
Abstract
A gene encoding a xylanase, named xynS20, was cloned from the ruminal fungus Neocallimastix patriciarum. The DNA sequence of xynS20 revealed that the gene was 1,008 bp in size and encoded amino acid sequences with a predicted molecular weight of 36 kDa. The amino acid sequence alignment showed that the highest sequence identity (28.4%) is with insect gut xylanase XYL6805. According to the sequence-based classification, a putative conserved domain of glycosyl hydrolase family 11 was detected at the N-terminus of XynS20 and a putative conserved domain of family 1 carbohydrate-binding module (CBM) was observed at the C-terminus of XynS20. An Asn-rich linker sequence was found between the N-terminal catalytic domain and the C-terminal CBM of XynS20. To examine the activity of the gene product, xynS20 gene was cloned as an oleosin-fused protein, expressed in Escherichia coli, affinity-purified by formation of artificial oil bodies, released from oleosin by intein-mediated peptide cleavage, and finally harvested by concentration of the supernatant. The specific activity of purified XynS20 toward oat spelt xylan was 1,982.8 U mg(-1). The recombinant XynS20 was stable in the mild acid pH range from 5.0 to 6.0, and the optimum pH was 6.0. The optimal reaction temperature of XynS20 was 45 degrees C; at temperatures below 30 and above 55 degrees C, enzyme activity was less than 50% of that at the optimal temperature.
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43
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Abstract
The flexibility of protein structures is important in allowing the variety of motions, covering a wide range of magnitudes and frequencies, essential to biological activity. Protein flexibility is also implicated in denaturation, allowing proteins to take up nonactive conformations that have free energies close to that of the native state. High-frequency dielectric measurement can be used to study the flexibility of proteins by probing the relaxation of dipolar constituents of their structures. In this work, 14 hydrated globular proteins are investigated using this method. Four relaxation processes are identified, one of which, with a relaxation time of 19 ns, can be correlated with the sum of the number densities of protein glycine and alanine residues. A second with a relaxation time of 2 ns shows a dependence on the number of threonine residues. It is concluded that the dipolar peptide groups of the protein backbone associated with these residues are responsible for these dielectric responses, with the lower frequency dispersion being due to backbone mobility in the hydrophobic environment of the protein core and the higher frequency response being associated with mobility on the more hydrophilic protein surface. The correlation of protein backbone flexibility with particular side chains indicates that these protein motions are under the direct control of the amino acid sequence of the protein.
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Affiliation(s)
- Stephen Bone
- Institute for Bioelectronic and Molecular Microsystems, Bangor University, Dean Street, Bangor LL571UT, Gwynedd, UK. s.bone@.bangor.ac.uk
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Characterization of a cellulose binding domain from Clostridium cellulovorans endoglucanase-xylanase D and its use as a fusion partner for soluble protein expression in Escherichia coli. J Biotechnol 2008; 135:319-25. [DOI: 10.1016/j.jbiotec.2008.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 04/23/2008] [Accepted: 05/02/2008] [Indexed: 11/19/2022]
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45
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Bertini I, Calderone V, Fragai M, Jaiswal R, Luchinat C, Melikian M, Mylonas E, Svergun DI. Evidence of reciprocal reorientation of the catalytic and hemopexin-like domains of full-length MMP-12. J Am Chem Soc 2008; 130:7011-21. [PMID: 18465858 DOI: 10.1021/ja710491y] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The proteolytic activity of matrix metalloproteinases toward extracellular matrix components (ECM), cytokines, chemokines, and membrane receptors is crucial for several homeostatic and pathological processes. Active MMPs are a family of single-chain enzymes (23 family members in the human genome), most of which constituted by a catalytic domain and by a hemopexin-like domain connected by a linker. The X-ray structures of MMP-1 and MMP-2 suggest a conserved and well-defined spatial relationship between the two domains. Here we present structural data for MMP-12, suitably stabilized against self-hydrolysis, both in solution (NMR and SAXS) and in the solid state (X-ray), showing that the hemopexin-like and the catalytic domains experience conformational freedom with respect to each other on a time scale shorter than 10(-8) s. Hints on the probable conformations are also obtained. This experimental finding opens new perspectives for the often hypothesized active role of the hemopexin-like domain in the enzymatic activity of MMPs.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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46
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Holland NB, Nishimiya Y, Tsuda S, Sönnichsen FD. Two domains of RD3 antifreeze protein diffuse independently. Biochemistry 2008; 47:5935-41. [PMID: 18459801 DOI: 10.1021/bi8001924] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Antifreeze proteins (AFPs) make up a class of structurally diverse proteins that help to protect many organisms from freezing temperatures by inhibiting ice crystal growth at temperatures below the colligative freezing point. AFPs are typically small proteins with a relatively flat, slightly hydrophobic binding region that matches the lattice structure of a specific ice crystal plane. The only known two-domain AFP is RD3 from the Antarctic eel pout. It consists of two nearly identical type III domains connected by a nine-residue linker. This protein exhibits higher activity than the single-domain protein at low concentrations. The initial solution structure of RD3 revealed that the domains were aligned so that the binding regions were nearly coplanar, effectively doubling the surface area for binding. A more recent report suggests that the domains may not be aligned in solution but rather diffuse independently. To resolve the issue, we have measured the NMR residual dipolar couplings using alignment media of stretched gels and filamentous phage to determine the relative orientation of the domains. We find that the two domains of RD3 are free to move relative to each other, within the constraint of the flexible nine-residue linker. Our data show that there is no strongly preferred alignment in solution. Furthermore, the flexibility and length of the linker are sufficient to allow the two domains to have their binding faces in the same orientation and coplanar for simultaneous binding to an ice crystal surface.
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Affiliation(s)
- Nolan B Holland
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
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47
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Sonan G, Receveur-Brechot V, Duez C, Aghajari N, Czjzek M, Haser R, Gerday C. The linker region plays a key role in the adaptation to cold of the cellulase from an Antarctic bacterium. Biochem J 2008; 407:293-302. [PMID: 17635108 PMCID: PMC2049020 DOI: 10.1042/bj20070640] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The psychrophilic cellulase, Cel5G, from the Antarctic bacterium Pseudoalteromonas haloplanktis is composed of a catalytic module (CM) joined to a carbohydrate-binding module (CBM) by an unusually long, extended and flexible linker region (LR) containing three loops closed by three disulfide bridges. To evaluate the possible role of this region in cold adaptation, the LR was sequentially shortened by protein engineering, successively deleting one and two loops of this module, whereas the last disulfide bridge was also suppressed by replacing the last two cysteine residue by two alanine residues. The kinetic and thermodynamic properties of the mutants were compared with those of the full-length enzyme, and also with those of the cold-adapted CM alone and with those of the homologous mesophilic enzyme, Cel5A, from Erwinia chrysanthemi. The thermostability of the mutated enzymes as well as their relative flexibility were evaluated by differential scanning calorimetry and fluorescence quenching respectively. The topology of the structure of the shortest mutant was determined by SAXS (small-angle X-ray scattering). The data indicate that the sequential shortening of the LR induces a regular decrease of the specific activity towards macromolecular substrates, reduces the relative flexibility and concomitantly increases the thermostability of the shortened enzymes. This demonstrates that the long LR of the full-length enzyme favours the catalytic efficiency at low and moderate temperatures by rendering the structure not only less compact, but also less stable, and plays a crucial role in the adaptation to cold of this cellulolytic enzyme.
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Affiliation(s)
- Guillaume K. Sonan
- *Laboratoire de Biochimie et Centre d'Ingénierie des Protéines, Institut de Chimie B6, Université de Liège, B-4000 Liège Sart-Tilman, Belgium
| | - Véronique Receveur-Brechot
- †Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS et Universités d'Aix-Marseille I et II, 163 avenue de Luminy, F-13488 Marseille cedex, France
| | - Colette Duez
- *Laboratoire de Biochimie et Centre d'Ingénierie des Protéines, Institut de Chimie B6, Université de Liège, B-4000 Liège Sart-Tilman, Belgium
| | - Nushin Aghajari
- ‡Laboratoire de Bio Cristallographie, Institut de Biologie et Chimie des Protéines, CNRS et Université Claude Bernard Lyon 1, UMR 5086, IFR 128 “Biosciences Lyon-Gerland”, 7 Passage du Vercors, F-69367 Lyon Cedex 07 France
| | - Mirjam Czjzek
- §Station Biologique de Roscoff, Végétaux Marins et Biomolécules, UMR 7139, Place George Teissier, BP 74, F-29682 Roscoff cedex, France
| | - Richard Haser
- ‡Laboratoire de Bio Cristallographie, Institut de Biologie et Chimie des Protéines, CNRS et Université Claude Bernard Lyon 1, UMR 5086, IFR 128 “Biosciences Lyon-Gerland”, 7 Passage du Vercors, F-69367 Lyon Cedex 07 France
| | - Charles Gerday
- *Laboratoire de Biochimie et Centre d'Ingénierie des Protéines, Institut de Chimie B6, Université de Liège, B-4000 Liège Sart-Tilman, Belgium
- To whom correspondence should be addressed (email )
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48
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Ludwiczek ML, Heller M, Kantner T, McIntosh LP. A secondary xylan-binding site enhances the catalytic activity of a single-domain family 11 glycoside hydrolase. J Mol Biol 2007; 373:337-54. [PMID: 17822716 DOI: 10.1016/j.jmb.2007.07.057] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 07/24/2007] [Indexed: 11/20/2022]
Abstract
Bacillus circulans xylanase (BcX) is a single-domain family 11 glycoside hydrolase. Using NMR-monitored titrations, we discovered that an inactive variant of this enzyme, E78Q-BcX, bound xylooligosaccharides not only within its pronounced active site (AS) cleft, but also at a distal surface region. Chemical shift perturbation mapping and affinity electrophoresis, combined with mutational studies, identified the xylan-specific secondary binding site (SBS) as a shallow groove lined by Asn, Ser, and Thr residues and with a Trp at one end. The AS and SBS bound short xylooligosaccharides with similar dissociation constants in the millimolar range. However, the on and off-rates to the SBS were at least tenfold faster than those of kon approximately 3x10(5) M(-1) s(-1) and koff approximately 1000 s(-1) measured for xylotetraose to the AS of E78Q-BcX. Consistent with their structural differences, this suggests that a conformational change in the enzyme and/or the substrate is required for association to and dissociation from the deep AS, but not the shallow SBS. In contrast to the independent binding of small xylooligosaccharides, high-affinity binding of soluble and insoluble xylan, as well as xylododecaose, occurred cooperatively to the two sites. This was evidenced by an approximately 100-fold increase in relative Kd values for these ligands upon mutation of the SBS. The SBS also enhances the activity of BcX towards soluble and insoluble xylan through a significant reduction in the Michaelis KM values for these polymeric substrates. This study provides an unexpected example of how a single domain family 11 xylanase overcomes the lack of a carbohydrate-binding module through the use of a secondary binding site to enhance substrate specificity and affinity.
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Affiliation(s)
- Martin L Ludwiczek
- Department of Biochemistry and Molecular Biology, Department of Chemistry, The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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49
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Abstract
The assembly of proteins that display complementary activities into supramolecular intra- and extracellular complexes is central to cellular function. One such nanomachine of considerable biological and industrial significance is the plant cell wall degrading apparatus of anaerobic bacteria termed the cellulosome. The Clostridium thermocellum cellulosome assembles through the interaction of a type I dockerin module in the catalytic entities with one of several type I cohesin modules in the non-catalytic scaffolding protein. Recent structural studies have provided the molecular details of how dockerin-cohesin interactions mediate both cellulosome assembly and the retention of the protein complex on the bacterial cell surface. The type I dockerin, which displays near-perfect sequence and structural symmetry, interacts with its cohesin partner through a dual binding mode in which either the N- or C-terminal helix dominate heterodimer formation. The biological significance of this dual binding mode is discussed with respect to the plasticity of the orientation of the catalytic subunits within this supramolecular assembly. The flexibility in the quaternary structure of the cellulosome may reflect the challenges presented by the degradation of a heterogenous recalcitrant insoluble substrate by an intricate macromolecular complex, in which the essential synergy between the catalytic subunits is a key feature of cellulosome function.
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Affiliation(s)
- Harry J Gilbert
- Institute for Cell and Molecular Biosciences, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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