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Biophysical and biochemical studies of a major endoglucanase secreted by Xanthomonas campestris pv. campestris. Enzyme Microb Technol 2016; 91:1-7. [PMID: 27444323 DOI: 10.1016/j.enzmictec.2016.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 05/14/2016] [Accepted: 05/20/2016] [Indexed: 12/23/2022]
Abstract
Endoglucanases are the main cellulolytic enzymes secreted by the bacterium Xanthomonas campestris pv. campestris (Xcc). The major endoglucanase exported by this bacterium into an external milieu is an enzyme XccCel5A, which belongs to GH5 family subfamily 1 and is encoded by the gene engXCA. We purified XccCel5A using ammonium sulfate precipitation followed by size exclusion chromatography and identified it by zymogram analysis. Circular dichroism and fluorescence spectroscopy studies showed that XccCel5A is stable in a wide pH range and up to about 55°C and denatures at the higher temperatures. The optimal conditions for enzyme activity were identified as T=45°C and pH=7.0. Under the optimum conditions the catalytic efficiency (kcat/KM) of the enzyme was determined as 5.16×10(4)s(-1)M(-1) using carboxymethylcellulose (CMC) as a substrate. Our SAXS studies revealed extended tadpole-shape molecular assembly, typical for cellulases, and allowed to determine an overall shape of the enzyme and a relative position of the catalytic and cellulose binding domains.
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2
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Hamid SBA, Islam MM, Das R. Cellulase biocatalysis: key influencing factors and mode of action. CELLULOSE 2015; 22:2157-2182. [DOI: 10.1007/s10570-015-0672-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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3
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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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4
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Bianchetti CM, Brumm P, Smith RW, Dyer K, Hura GL, Rutkoski TJ, Phillips GN. Structure, dynamics, and specificity of endoglucanase D from Clostridium cellulovorans. J Mol Biol 2013; 425:4267-85. [PMID: 23751954 PMCID: PMC4039632 DOI: 10.1016/j.jmb.2013.05.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 05/22/2013] [Accepted: 05/30/2013] [Indexed: 11/17/2022]
Abstract
The enzymatic degradation of cellulose is a critical step in the biological conversion of plant biomass into an abundant renewable energy source. An understanding of the structural and dynamic features that cellulases utilize to bind a single strand of crystalline cellulose and hydrolyze the β-1,4-glycosidic bonds of cellulose to produce fermentable sugars would greatly facilitate the engineering of improved cellulases for the large-scale conversion of plant biomass. Endoglucanase D (EngD) from Clostridium cellulovorans is a modular enzyme comprising an N-terminal catalytic domain and a C-terminal carbohydrate-binding module, which is attached via a flexible linker. Here, we present the 2.1-Å-resolution crystal structures of full-length EngD with and without cellotriose bound, solution small-angle X-ray scattering (SAXS) studies of the full-length enzyme, the characterization of the active cleft glucose binding subsites, and substrate specificity of EngD on soluble and insoluble polymeric carbohydrates. SAXS data support a model in which the linker is flexible, allowing EngD to adopt an extended conformation in solution. The cellotriose-bound EngD structure revealed an extended active-site cleft that contains seven glucose-binding subsites, but unlike the majority of structurally determined endocellulases, the active-site cleft of EngD is partially enclosed by Trp162 and Tyr232. EngD variants, which lack Trp162, showed a significant reduction in activity and an alteration in the distribution of cellohexaose degradation products, suggesting that Trp162 plays a direct role in substrate binding.
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Affiliation(s)
- Christopher M. Bianchetti
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI 53706, USA
| | - Phillip Brumm
- Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI 53706, USA
- Lucigen Corporation and C5-6 Technologies, Madison WI 53562, USA
| | - Robert W. Smith
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI 53706, USA
| | - Kevin Dyer
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Greg L. Hura
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Thomas J. Rutkoski
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI 53706, USA
| | - George N. Phillips
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, WI 53706, USA
- Department of Biochemistry and Cell Biology Rice University, Houston, TX 77005
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5
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Lima MA, Oliveira-Neto M, Kadowaki MAS, Rosseto FR, Prates ET, Squina FM, Leme AFP, Skaf MS, Polikarpov I. Aspergillus niger β-glucosidase has a cellulase-like tadpole molecular shape: insights into glycoside hydrolase family 3 (GH3) β-glucosidase structure and function. J Biol Chem 2013; 288:32991-3005. [PMID: 24064212 DOI: 10.1074/jbc.m113.479279] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aspergillus niger is known to secrete large amounts of β-glucosidases, which have a variety of biotechnological and industrial applications. Here, we purified an A. niger β-glucosidase (AnBgl1) and conducted its biochemical and biophysical analyses. Purified enzyme with an apparent molecular mass of 116 kDa forms monomers in solution as judged by native gel electrophoresis and has a pI value of 4.55, as found for most of the fungi of β-glucosidases. Surprisingly, the small angle x-ray experiments reveal that AnBgl1 has a tadpole-like structure, with the N-terminal catalytic domain and C-terminal fibronectin III-like domain (FnIII) connected by the long linker peptide (∼100 amino acid residues) in an extended conformation. This molecular organization resembles the one adopted by other cellulases (such as cellobiohydrolases, for example) that frequently contain a catalytic domain linked to the cellulose-binding module that mediates their binding to insoluble and polymeric cellulose. The reasons why AnBgl1, which acts on the small soluble substrates, has a tadpole molecular shape are not entirely clear. However, our enzyme pulldown assays with different polymeric substrates suggest that AnBgl1 has little or no capacity to bind to and to adsorb cellulose, xylan, and starch, but it has high affinity to lignin. Molecular dynamics simulations suggested that clusters of residues located in the C-terminal FnIII domain interact strongly with lignin fragments. The simulations showed that numerous arginine residues scattered throughout the FnIII surface play an important role in the interaction with lignin by means of cation-π stacking with the lignin aromatic rings. These results indicate that the C-terminal FnIII domain could be operational for immobilization of the enzyme on the cell wall and for the prevention of unproductive binding of cellulase to the biomass lignin.
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Affiliation(s)
- Marisa A Lima
- From the Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos 13560-970, SP
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6
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Serag MF, Kaji N, Tokeshi M, Baba Y. Introducing carbon nanotubes into living walled plant cells through cellulase-induced nanoholes. RSC Adv 2012. [DOI: 10.1039/c1ra00760b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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8
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Quirk A, Lipkowski J, Vandenende C, Cockburn D, Clarke AJ, Dutcher JR, Roscoe SG. Direct visualization of the enzymatic digestion of a single fiber of native cellulose in an aqueous environment by atomic force microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:5007-13. [PMID: 20170174 DOI: 10.1021/la9037028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Atomic force microscopy (AFM) was used to study native cellulose films prepared from a bacterial cellulose source, Acetobacter xylinum, using a novel application of the Langmuir-Blodgett technique. These films allowed high-resolution AFM images of single fibers and their microfibril structure to be obtained. Two types of experiments were performed. First, the fibers were characterized using samples that were dried after LB deposition. Next, novel protocols that allowed us to image single fibers of cellulose in films that were never dried were developed. This procedure allowed us to perform in situ AFM imaging studies of the enzymatic hydrolysis of single cellulose fibers in solution using cellulolytic enzymes. The in situ degradation of cellulose fibers was monitored over a 9 h period using AFM. These studies provided the first direct, real-time images of the enzymatic degradation of a single cellulose fiber. We have demonstrated the tremendous potential of AFM to study the mechanism of the enzymatic digestion of cellulose and to identify the most effective enzymes for the digestion of various cellulose structures or isomorphs.
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Affiliation(s)
- Amanda Quirk
- Department of Chemistry, University of Guelph, Guelph, Ontario, N1G 2W1 Canada
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9
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Poon DKY, Withers SG, McIntosh LP. Direct demonstration of the flexibility of the glycosylated proline-threonine linker in the Cellulomonas fimi Xylanase Cex through NMR spectroscopic analysis. J Biol Chem 2006; 282:2091-100. [PMID: 17121820 DOI: 10.1074/jbc.m609670200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The modular xylanase Cex (or CfXyn10A) from Cellulomonas fimi consists of an N-terminal catalytic domain and a C-terminal cellulose-binding domain, joined by a glycosylated proline-threonine (PT) linker. To characterize the conformation and dynamics of the Cex linker and the consequences of its modification, we have used NMR spectroscopy to study full-length Cex in its nonglycosylated ( approximately 47 kDa) and glycosylated ( approximately 51 kDa) forms. The PT linker lacks any predominant structure in either form as indicated by random coil amide chemical shifts. Furthermore, heteronuclear (1)H-(15)N nuclear Overhauser effect relaxation measurements demonstrate that the linker is flexible on the ns-to-ps time scale and that glycosylation partially dampens this flexibility. The catalytic and cellulose-binding domains also exhibit identical amide chemical shifts whether in isolation or in the context of either unmodified or glycosylated full-length Cex. Therefore, there are no noncovalent interactions between the two domains of Cex or between either domain and the linker. This conclusion is supported by the distinct (15)N relaxation properties of the two domains, as well as their differential alignment within a magnetic field by Pf1 phage particles. These data demonstrate that the PT linker is a flexible tether, joining the structurally independent catalytic and cellulose-binding domains of Cex in an ensemble of conformations; however, more extended forms may predominate because of restrictions imparted by the alternating proline residues. This supports the postulate that the binding-domain anchors Cex to the surface of cellulose, whereas the linker provides flexibility for the catalytic domain to hydrolyze nearby hemicellulose (xylan) chains.
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Affiliation(s)
- David K Y Poon
- Department of Biochemistry and Molecular Biology, The Protein Engineering Network of Centres of Excellence, and The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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10
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Abstract
Cellulomonas is a unique bacterium possessing not only the capacity to degrade various carbohydrates, such as starch, xylan and cellulose, but crystalline cellulose as well. It has developed a complex battery of glucanases to deal with substrates possessing such extensive microheterogeneities. Some of these enzymes are multifunctional, as well as cross inducible, possessing a multi-domain structure; these enzymes are thought to have arisen by the shuffling of these domains. Intergeneric hybrids have been constructed between Cellulomonas and Zymomonas so as to enhance the industrial potential of this organism. This review examines the unique features of this microorganism and evaluates its key role in the conversion of complex wastes to useful products, by virtue of its unusual attributes.
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Affiliation(s)
- P Chaudhary
- Molecular Biology Research Laboratory, Department of Zoology, University of Poona, Pune-411 007, India
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11
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Receveur V, Czjzek M, Schülein M, Panine P, Henrissat B. Dimension, shape, and conformational flexibility of a two domain fungal cellulase in solution probed by small angle X-ray scattering. J Biol Chem 2002; 277:40887-92. [PMID: 12186865 DOI: 10.1074/jbc.m205404200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellulase Cel45 from Humicola insolens has a modular structure with a catalytic module and a cellulose-binding module (CBM) separated by a 36 amino acid, glycosylated, linker peptide. The solution conformation of the entire two domain Cel45 protein as well as the effect of the length and flexibility of the linker on the spatial arrangement of the constitutive modules were studied by small angle x-ray scattering combined with the known three-dimensional structure of the individual modules. The measured dimensions of the enzyme show that the linker exhibits an extended conformation leading to a maximum extension between the two centers of mass of each module corresponding to about four cellobiose units on a cellulose chain. The glycosylation of the linker is the key factor defining its extended conformation, and a five proline stretch mutation on the linker was found to confer a higher rigidity to the enzyme. Our study shows that the respective positioning of the catalytic module and the CBM onto the insoluble substrate is most likely influenced by the linker structure and flexibility. Our results are consistent with a model where cellulases can move on the surface of cellulose with a caterpillar-like displacement with free energy restrictions.
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Affiliation(s)
- Véronique Receveur
- Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS and Universités d'Aix-Marseille I and II, 31 Chemin Joseph Aiguier, 13402 Marseille cedex 20, France.
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12
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Genetics and Properties of Cellulases. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2001. [DOI: 10.1007/3-540-49194-5_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
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13
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Suvajittanont W, McGuire J, Bothwell MK. Adsorption of thermomonospora fusca E(5) cellulase on silanized silica. Biotechnol Bioeng 2000; 67:12-8. [PMID: 10581431 DOI: 10.1002/1097-0290(20000105)67:1<12::aid-bit2>3.0.co;2-#] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The adsorption kinetics and dodeceyltrimethylammonium-bromide-mediated elution of Thermomonospora fusca E(5) cellulase were recorded in situ, at hydrophobic, silanized silica. Experiments were performed at different solution concentrations, ranging from 0.001 to 0.70 mg/mL. Plateau values of adsorbed mass generally increased with increasing solution concentration, with the adsorbed layer being only partially eluted by buffer. Treatment with surfactant removed more of the adsorbed enzyme in each case, with the remaining adsorbed mass varying little among experiments. Adsorption of E(5) into this nonremovable state was suggested to occur early in the adsorption process and continue until some critical surface concentration was reached. Beyond this critical value of adsorbed mass, adsorption progressed with the protein adopting more loosely bound states. Adsorption kinetic data were interpreted with reference to an adsorption mechanism allowing for irreversible adsorption into two dissimilar states. These states were distinguished by differences in occupied interfacial area, and binding strength, presumably a result of differences in structure. Comparison of the data to the kinetic model based on this mechanism showed that the fraction of adsorbed molecules present in the more tightly bound state decreased as adsorption occurred from solutions of increasing concentration. However, the absolute values of more tightly bound molecules were less dependent on adsorption conditions.
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Affiliation(s)
- W Suvajittanont
- Bioengineering, Oregon State University, 116 Gilmore Hall, Corvallis, Oregon 97331-3906, USA
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14
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Chacón P, Morán F, Díaz JF, Pantos E, Andreu JM. Low-resolution structures of proteins in solution retrieved from X-ray scattering with a genetic algorithm. Biophys J 1998; 74:2760-75. [PMID: 9635731 PMCID: PMC1299618 DOI: 10.1016/s0006-3495(98)77984-6] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Small-angle x-ray solution scattering (SAXS) is analyzed with a new method to retrieve convergent model structures that fit the scattering profiles. An arbitrary hexagonal packing of several hundred beads containing the problem object is defined. Instead of attempting to compute the Debye formula for all of the possible mass distributions, a genetic algorithm is employed that efficiently searches the configurational space and evolves best-fit bead models. Models from different runs of the algorithm have similar or identical structures. The modeling resolution is increased by reducing the bead radius together with the search space in successive cycles of refinement. The method has been tested with protein SAXS (0.001 < S < 0.06 A(-1)) calculated from x-ray crystal structures, adding noise to the profiles. The models obtained closely approach the volumes and radii of gyration of the known structures, and faithfully reproduce the dimensions and shape of each of them. This includes finding the active site cavity of lysozyme, the bilobed structure of gamma-crystallin, two domains connected by a stalk in betab2-crystallin, and the horseshoe shape of pancreatic ribonuclease inhibitor. The low-resolution solution structure of lysozyme has been directly modeled from its experimental SAXS profile (0.003 < S < 0.03 A(-1)). The model describes lysozyme size and shape to the resolution of the measurement. The method may be applied to other proteins, to the analysis of domain movements, to the comparison of solution and crystal structures, as well as to large macromolecular assemblies.
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Affiliation(s)
- P Chacón
- Centro de Investigaciones Biológicas, C.S.I.C. Velázquez 144, Madrid, Spain
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15
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Lehner D, Zipper P, Henriksson G, Pettersson G. Small-angle X-ray scattering studies on cellobiose dehydrogenase from Phanerochaete chrysosporium. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1293:161-9. [PMID: 8652622 DOI: 10.1016/0167-4838(95)00245-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Limited proteolysis of cellobiose dehydrogenase (CDH) from the white rot fungus Phanerochaete chrysosporium by papain cleaves the enzyme into two fragments containing flavin (FAD) and heme, respectively. Small-angle X-ray scattering (SAXS) was employed to investigate size and shape of intact CDH and of its fragments in solution. The largest dimension of CDH amounts to about 18 nm, whereas the corresponding quantity of each of the two fragments is only around 9 nm. CDH as well as its fragments appear to be of prolate shape, the cross-section of the FAD fragment (diameter 4.3 to 5.1 nm) being considerably larger than that of the heme fragment (diameter 3.3 nm). These findings suggest a collinear arrangement of the two domains in the CDH particle. Simulations based on the method of finite elements corroborate this structure model and furthermore suggest the existence of a possibly flexible linker between the two domains.
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Affiliation(s)
- D Lehner
- Institute of Physical Chemistry, University of Graz, Austria
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16
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Brun E, Gans P, Marion D, Barras F. Overproduction, Purification and Characterization of the Cellulose-Binding Domain of the Erwinia Chrysanthemi Secreted Endoglucanase EGZ. ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1432-1033.1995.0142f.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Kleman-Leyer KM, Gilkes NR, Miller RC, Kirk TK. Changes in the molecular-size distribution of insoluble celluloses by the action of recombinant Cellulomonas fimi cellulases. Biochem J 1994; 302 ( Pt 2):463-9. [PMID: 8092998 PMCID: PMC1137251 DOI: 10.1042/bj3020463] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Specific patterns of attacks of cotton, bacterial cellulose and bacterial microcrystalline cellulose (BMCC) by recombinant cellulases of Cellulomonas fimi were investigated. Molecular-size distributions of the celluloses were determined by high-performance size-exclusion chromatography. Chromatography of cotton and bacterial celluloses revealed single major peaks centered over progressively lower molecular-mass positions during attack by endoglucanase CenA. In advanced stages, a second peak appeared at very low average size (approx. 11 glucosyl units); ultimate weight losses were approximately 30%. The isolated catalytic domain of CenA, p30, gave results very similar to those with complete CenA. CenA did not effectively depolymerize or solubilize BMCC significantly. Molecular-size distributions of cotton and bacterial cellulose incubated with endoglucanases CenB or CenD exhibited one major peak regardless of incubation time; low-molecular-mass fragments did not accumulate. Weight losses were 40 and 35% respectively. The single peak shifted to lower-molecular-mass positions as incubation continued, but high-molecular-mass material persisted. CenB and CenD readily attacked and solubilized BMCC (approx. 70%). We conclude that CenA attacks cellulose by preferentially cleaving completely through the cellulose microfibrils at the amorphous sites, and much more slowly by degrading the crystalline surfaces. Conversely, CenB and CenD cleave the amorphous regions much less efficiently while vigorously degrading the surfaces of the crystalline regions of the microfibrils.
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Affiliation(s)
- K M Kleman-Leyer
- Department of Bacteriology, University of Wisconsin-Madison 53706
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18
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Din N, Forsythe IJ, Burtnick LD, Gilkes NR, Miller RC, Warren RA, Kilburn DG. The cellulose-binding domain of endoglucanase A (CenA) from Cellulomonas fimi: evidence for the involvement of tryptophan residues in binding. Mol Microbiol 1994; 11:747-55. [PMID: 8196546 DOI: 10.1111/j.1365-2958.1994.tb00352.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cellulomonas fimi endo-beta-1,4-glucanase A (CenA) contains a discrete N-terminal cellulose-binding domain (CBDCenA). Related CBDs occur in at least 16 bacterial glycanases and are characterized by four highly conserved Trp residues, two of which correspond to W14 and W68 of CBDCenA. The adsorption of CBDCenA to crystalline cellulose was compared with that of two Trp mutants (W14A and W68A). The affinities of the mutant CBDs for cellulose were reduced by approximately 50- and 30-fold, respectively, relative to the wild type. Physical measurements indicated that the mutant CBDs fold normally. Fluorescence data indicated that W14 and W68 were exposed on the CBD, consistent with their participation in binding to cellobiosyl residues on the cellulose surface.
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Affiliation(s)
- N Din
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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19
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Gilkes NR, Kilburn DG, Miller RC, Warren RA, Sugiyama J, Chanzy H, Henrissat B. Visualization of the adsorption of a bacterial endo-beta-1,4-glucanase and its isolated cellulose-binding domain to crystalline cellulose. Int J Biol Macromol 1993; 15:347-51. [PMID: 8110656 DOI: 10.1016/0141-8130(93)90052-n] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Endo-beta-1,4-glucanase A (CenA), a cellulase from the bacterium Cellulomonas fimi, is composed of two domains: a catalytic domain and a cellulose-binding domain. Adsorption of CenA and its isolated cellulose-binding domain (CBD.PTCenA) to Valonia cellulose microcrystals was examined by transmission electron microscopy using an antibody sandwich technique (CenA/CBD.PTCenA-alpha CenA IgG-protein A-gold conjugate). Adsorption of both CenA and CBD.PTCenA occurred along the lengths of the microcrystals, with an apparent preference for certain crystal faces or edges. CenA or CBD.PTCenA, but not the isolated catalytic domain, were shown to prevent the flocculation of microcrystalline bacterial cellulose. The cellulose-binding domain may assist crystalline cellulose hydrolysis in vitro by promoting substrate dispersion.
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Affiliation(s)
- N R Gilkes
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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20
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Bedarkar S, Gilkes NR, Kilburn DG, Kwan E, Rose DR, Miller RC, Warren RA, Withers SG. Crystallization and preliminary X-ray diffraction analysis of the catalytic domain of Cex, an exo-beta-1,4-glucanase and beta-1,4-xylanase from the bacterium Cellulomonas fimi. J Mol Biol 1992; 228:693-5. [PMID: 1453471 DOI: 10.1016/0022-2836(92)90852-b] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Single crystals of the catalytic domain of Cex, an exo-beta-1,4-glucanase and beta-1,4-xylanase from the cellulolytic bacterium Cellulomonas fimi, have been grown in the presence of polyethylene glycol 4000 using the vapour diffusion technique. The crystals, which diffract to better than 2.0 A resolution, belong to space group P4(1)2(1)2 or P4(3)2(1)2 and have cell constants: a = b = 88.21 A, c = 81.10 A; alpha = beta = gamma = 90 degrees.
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Affiliation(s)
- S Bedarkar
- Ontario Cancer Institute, Toronto, Canada
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Gilkes N, Jervis E, Henrissat B, Tekant B, Miller RC, Warren R, Kilburn D. The adsorption of a bacterial cellulase and its two isolated domains to crystalline cellulose. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50488-4] [Citation(s) in RCA: 187] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Miller PB, Shen H, Gilkes NR, Kilburn DG, Miller RC, Plaut AG, Warren RJ. Endoglucanase A fromCellulomonas fimiin which the hinge sequence of human IgA1 is substituted for the linker connecting its two domains is hydrolyzed by IgA proteases fromNeisseria gonorrhoeae. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05259.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Gilkes NR, Claeyssens M, Aebersold R, Henrissat B, Meinke A, Morrison HD, Kilburn DG, Warren RA, Miller RC. Structural and functional relationships in two families of beta-1,4-glycanases. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 202:367-77. [PMID: 1761039 DOI: 10.1111/j.1432-1033.1991.tb16384.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
CenA and Cex are beta-1,4-glycanases produced by the cellulolytic bacterium Cellulomonas fimi. Both enzymes are composed of two domains and contain six Cys residues. Two disulfide bonds were assigned in both enzymes by peptide analysis of the isolated catalytic domains. A further disulfide bond was deduced in both cellulose-binding domains from the absence of free thiols under denaturing conditions. Corresponding Cys residues are conserved in eight of nine other known C. fimi-type cellulose-binding domains. CenA and Cex belong to families B and F, respectively, in the classification of beta-1,4-glucanases and beta-1,4-xylanases based on similarities in catalytic domain primary structure. Disulfide bonds in the CenA catalytic domain correspond to the two disulfide bonds in the catalytic domain of Trichoderma reesei cellobiohydrolase II (family B) which stabilize loops forming the active-site tunnel. Sequence alignment indicates the probable occurrence of disulfides at equivalent positions in the two other family B enzymes. Partial resequencing of the gene encoding Streptomyces KSM-9 beta-1,4-glucanase CasA (family B) revealed five errors in the original nucleotide sequence analysis. The corrected amino acid sequence contains an Asp residue corresponding to the proposed proton donor in hydrolysis catalysed by cellobiohydrolase II. Cys residues which form disulfide bonds in the Cex catalytic domain are conserved in XynZ of Clostridium thermocellum and Xyn of Cryptococcus albidus but not in the other eight known family F enzymes. Like other members of its family, Cex catalyses xylan hydrolysis. The catalytic efficiency (kcat/Km) for hydrolysis of the heterosidic bond of p-nitrophenyl-beta-D-xylobioside is 14,385 min-1.mM-1 at 25 degrees C; the corresponding kcat/Km for p-nitrophenyl-beta-D-cellobioside hydrolysis is 296 min-1.mM-1.
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Affiliation(s)
- N R Gilkes
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Fierobe HP, Gaudin C, Belaich A, Loutfi M, Faure E, Bagnara C, Baty D, Belaich JP. Characterization of endoglucanase A from Clostridium cellulolyticum. J Bacteriol 1991; 173:7956-62. [PMID: 1744052 PMCID: PMC212590 DOI: 10.1128/jb.173.24.7956-7962.1991] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A construction was carried out to obtain a high level of expression in Escherichia coli of the gene celCCA, coding for the endoglucanase A from Clostridium cellulolyticum (EGCCA). The enzyme was purified in two forms with different molecular weights, 51,000 and 44,000. The smaller protein was probably the result of proteolysis, although great care was taken to prevent this process from occurring. Evidence was found for the loss of the conserved reiterated domains which are characteristic of C. thermocellum and C. cellulolyticum cellulases. The two forms were extensively studied, and it was demonstrated that although they had the same pH and temperature optima, they differed in their catalytic properties. The truncated protein gave the more efficient catalytic parameters on carboxymethyl cellulose and showed improved endoglucanase characteristics, whereas the intact enzyme showed truer cellulase characteristics. The possible role of clostridial reiterated domains in the hydrolytic activity toward crystalline cellulose is discussed.
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Affiliation(s)
- H P Fierobe
- Laboratoire de Chimie Bactérienne, Marseille, France
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Non–Hydrolytic Disruption of Cellulose Fibres by the Binding Domain of a Bacterial Cellulase. ACTA ACUST UNITED AC 1991. [DOI: 10.1038/nbt1191-1096] [Citation(s) in RCA: 222] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Shen H, Schmuck M, Pilz I, Gilkes N, Kilburn D, Miller R, Warren R. Deletion of the linker connecting the catalytic and cellulose-binding domains of endoglucanase A (CenA) of Cellulomonas fimi alters its conformation and catalytic activity. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99167-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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