1
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Dantuluri S, Abdullahu L, Munir A, Katolik A, Damha MJ, Shuman S. Substrate analogs that trap the 2'-phospho-ADP-ribosylated RNA intermediate of the Tpt1 (tRNA 2'-phosphotransferase) reaction pathway. RNA 2020; 26:373-381. [PMID: 31932322 PMCID: PMC7075268 DOI: 10.1261/rna.074377.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/10/2020] [Indexed: 05/06/2023]
Abstract
The enzyme Tpt1 removes an internal RNA 2'-PO4 via a two-step reaction in which: (i) the 2'-PO4 attacks NAD+ to form an RNA-2'-phospho-(ADP-ribose) intermediate and nicotinamide; and (ii) transesterification of the ADP-ribose O2″ to the RNA 2'-phosphodiester yields 2'-OH RNA and ADP-ribose-1″,2″-cyclic phosphate. Because step 2 is much faster than step 1, the ADP-ribosylated RNA intermediate is virtually undetectable under normal circumstances. Here, by testing chemically modified nucleic acid substrates for activity with bacterial Tpt1 enzymes, we find that replacement of the ribose-2'-PO4 nucleotide with arabinose-2'-PO4 selectively slows step 2 of the reaction pathway and results in the transient accumulation of high levels of the reaction intermediate. We report that replacing the NMN ribose of NAD+ with 2'-fluoroarabinose (thereby eliminating the ribose O2″ nucleophile) results in durable trapping of RNA-2'-phospho-(ADP-fluoroarabinose) as a "dead-end" product of step 1. Tpt1 enzymes from diverse taxa differ in their capacity to use ara-2″F-NAD+ as a substrate.
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Affiliation(s)
- Swathi Dantuluri
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Leonora Abdullahu
- Department of Chemistry, McGill University, Montreal, Quebec H3A0B8, Canada
| | - Annum Munir
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Adam Katolik
- Department of Chemistry, McGill University, Montreal, Quebec H3A0B8, Canada
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec H3A0B8, Canada
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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2
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Koendjbiharie JG, Hon S, Pabst M, Hooftman R, Stevenson DM, Cui J, Amador-Noguez D, Lynd LR, Olson DG, van Kranenburg R. The pentose phosphate pathway of cellulolytic clostridia relies on 6-phosphofructokinase instead of transaldolase. J Biol Chem 2020; 295:1867-1878. [PMID: 31871051 PMCID: PMC7029132 DOI: 10.1074/jbc.ra119.011239] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/16/2019] [Indexed: 01/24/2023] Open
Abstract
The genomes of most cellulolytic clostridia do not contain genes annotated as transaldolase. Therefore, for assimilating pentose sugars or for generating C5 precursors (such as ribose) during growth on other (non-C5) substrates, they must possess a pathway that connects pentose metabolism with the rest of metabolism. Here we provide evidence that for this connection cellulolytic clostridia rely on the sedoheptulose 1,7-bisphosphate (SBP) pathway, using pyrophosphate-dependent phosphofructokinase (PPi-PFK) instead of transaldolase. In this reversible pathway, PFK converts sedoheptulose 7-phosphate (S7P) to SBP, after which fructose-bisphosphate aldolase cleaves SBP into dihydroxyacetone phosphate and erythrose 4-phosphate. We show that PPi-PFKs of Clostridium thermosuccinogenes and Clostridium thermocellum indeed can convert S7P to SBP, and have similar affinities for S7P and the canonical substrate fructose 6-phosphate (F6P). By contrast, (ATP-dependent) PfkA of Escherichia coli, which does rely on transaldolase, had a very poor affinity for S7P. This indicates that the PPi-PFK of cellulolytic clostridia has evolved the use of S7P. We further show that C. thermosuccinogenes contains a significant SBP pool, an unusual metabolite that is elevated during growth on xylose, demonstrating its relevance for pentose assimilation. Last, we demonstrate that a second PFK of C. thermosuccinogenes that operates with ATP and GTP exhibits unusual kinetics toward F6P, as it appears to have an extremely high degree of cooperative binding, resulting in a virtual on/off switch for substrate concentrations near its K½ value. In summary, our results confirm the existence of an SBP pathway for pentose assimilation in cellulolytic clostridia.
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Affiliation(s)
| | - Shuen Hon
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755; Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830
| | - Martin Pabst
- Cell Systems Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Robert Hooftman
- Laboratory of Microbiology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
| | - David M Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Jingxuan Cui
- Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830; Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, 03755
| | - Daniel Amador-Noguez
- Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830; Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Lee R Lynd
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755; Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830; Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, 03755
| | - Daniel G Olson
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755; Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830
| | - Richard van Kranenburg
- Corbion, 4206 AC Gorinchem, The Netherlands; Laboratory of Microbiology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands.
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3
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Yoav S, Stern J, Salama-Alber O, Frolow F, Anbar M, Karpol A, Hadar Y, Morag E, Bayer EA. Directed Evolution of Clostridium thermocellum β-Glucosidase A Towards Enhanced Thermostability. Int J Mol Sci 2019; 20:E4701. [PMID: 31547488 PMCID: PMC6801902 DOI: 10.3390/ijms20194701] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/19/2019] [Accepted: 09/20/2019] [Indexed: 12/27/2022] Open
Abstract
β-Glucosidases are key enzymes in the process of cellulose utilization. It is the last enzyme in the cellulose hydrolysis chain, which converts cellobiose to glucose. Since cellobiose is known to have a feedback inhibitory effect on a variety of cellulases, β-glucosidase can prevent this inhibition by hydrolyzing cellobiose to non-inhibitory glucose. While the optimal temperature of the Clostridium thermocellum cellulosome is 70 °C, C. thermocellum β-glucosidase A is almost inactive at such high temperatures. Thus, in the current study, a random mutagenesis directed evolutionary approach was conducted to produce a thermostable mutant with Kcat and Km, similar to those of the wild-type enzyme. The resultant mutant contained two mutations, A17S and K268N, but only the former was found to affect thermostability, whereby the inflection temperature (Ti) was increased by 6.4 °C. A17 is located near the central cavity of the native enzyme. Interestingly, multiple alignments revealed that position 17 is relatively conserved, whereby alanine is replaced only by serine. Upon the addition of the thermostable mutant to the C. thermocellum secretome for subsequent hydrolysis of microcrystalline cellulose at 70 °C, a higher soluble glucose yield (243%) was obtained compared to the activity of the secretome supplemented with the wild-type enzyme.
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Affiliation(s)
- Shahar Yoav
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, the Advanced School for Environmental Studies, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Orly Salama-Alber
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Felix Frolow
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Michael Anbar
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Alon Karpol
- CelDezyner, 2 Bergman St, Tamar Science Park, Rehovot 7670504, Israel.
| | - Yitzhak Hadar
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, the Advanced School for Environmental Studies, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Ely Morag
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel.
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Pavlenko OS, Gra OA, Mustafaev ON, Kabarbaeva KV, Sadovskaya NS, Tyurin AA, Fadeev VS, Goldenkova-Pavlova IV. Thermostable Lichenase from Clostridium thermocellum as a Host Protein in the Domain Insertion Approach. Biochemistry (Mosc) 2019; 84:931-940. [PMID: 31522675 DOI: 10.1134/s0006297919080091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 12/17/2023]
Abstract
Clostridium thermocellum lichenase (endo-β-1,3;1,4-glucan-D-glycosyl hydrolase, EC 3.2.1.73 (P29716)) has been tested for the insertion of two model fluorescent proteins (EGFP and TagRFP) into two regions of this enzyme. Functional folding of the resulting proteins was confirmed by retention of lichenase activity and EGFP and TagRFP fluorescence. These results convincingly demonstrate that (i) the two experimentally selected lichenase loop regions may serve as the areas for domain insertion without disturbing enzyme folding in vivo; (ii) lichenase permits not only single but also tandem insertions of large protein domains. High specific activity, outstanding thermostability, and efficient in vitro refolding of thermostable lichenase make it an attractive new host protein for the insertional fusion of domains in the engineering of multifunctional proteins.
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Affiliation(s)
- O S Pavlenko
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia.
| | - O A Gra
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia
| | - O N Mustafaev
- Baku State University, Department of Biophysics and Molecular Biology, Baku, AZ1106, Azerbaijan.
| | - K V Kabarbaeva
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia
| | - N S Sadovskaya
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia
| | - A A Tyurin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia
| | - V S Fadeev
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia
| | - I V Goldenkova-Pavlova
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia.
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5
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Munir A, Abdullahu L, Banerjee A, Damha MJ, Shuman S. NAD +-dependent RNA terminal 2' and 3' phosphomonoesterase activity of a subset of Tpt1 enzymes. RNA 2019; 25:783-792. [PMID: 31019096 PMCID: PMC6573784 DOI: 10.1261/rna.071142.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/04/2019] [Indexed: 05/06/2023]
Abstract
The enzyme Tpt1 removes the 2'-PO4 at the splice junction generated by fungal tRNA ligase; it does so via a two-step reaction in which (i) the internal RNA 2'-PO4 attacks NAD+ to form an RNA-2'-phospho-ADP-ribosyl intermediate; and (ii) transesterification of the ribose O2″ to the 2'-phosphodiester yields 2'-OH RNA and ADP-ribose-1″,2″-cyclic phosphate products. The role that Tpt1 enzymes play in taxa that have no fungal-type RNA ligase remains obscure. An attractive prospect is that Tpt1 enzymes might catalyze reactions other than internal RNA 2'-PO4 removal, via their unique NAD+-dependent transferase mechanism. This study extends the repertoire of the Tpt1 enzyme family to include the NAD+-dependent conversion of RNA terminal 2' and 3' monophosphate ends to 2'-OH and 3'-OH ends, respectively. The salient finding is that different Tpt1 enzymes vary in their capacity and positional specificity for terminal phosphate removal. Clostridium thermocellum and Aeropyrum pernix Tpt1 proteins are active on 2'-PO4 and 3'-PO4 ends, with a 2.4- to 2.6-fold kinetic preference for the 2'-PO4 The accumulation of a terminal 3'-phospho-ADP-ribosylated RNA intermediate during the 3'-phosphotransferase reaction suggests that the geometry of the 3'-p-ADPR adduct is not optimal for the ensuing transesterification step. Chaetomium thermophilum Tpt1 acts specifically on a terminal 2'-PO4 end and not with a 3'-PO4 In contrast, Runella slithyformis Tpt1 and human Tpt1 are ineffective in removing either a 2'-PO4 or 3'-PO4 end.
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Affiliation(s)
- Annum Munir
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Leonora Abdullahu
- Department of Chemistry, McGill University, Montreal, Quebec, Canada H3A0B8
| | - Ankan Banerjee
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec, Canada H3A0B8
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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6
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Nath P, Dhillon A, Kumar K, Sharma K, Jamaldheen SB, Moholkar VS, Goyal A. Development of bi-functional chimeric enzyme (CtGH1-L1-CtGH5-F194A) from endoglucanase (CtGH5) mutant F194A and β-1,4-glucosidase (CtGH1) from Clostridium thermocellum with enhanced activity and structural integrity. Bioresour Technol 2019; 282:494-501. [PMID: 30897487 DOI: 10.1016/j.biortech.2019.03.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/08/2019] [Accepted: 03/09/2019] [Indexed: 06/09/2023]
Abstract
Site-directed mutagenesis of β-1,4-endoglucanase from family 5 glycoside hydrolase (CtGH5) from Clostridium thermocellum was performed to develop a mutant CtGH5-F194A that gave 40 U/mg specific activity against carboxymethyl cellulose, resulting 2-fold higher activity than wild-type CtGH5. CtGH5-F194A was fused with a β-1,4-glucosidase, CtGH1 from Clostridium thermocellum to develop a chimeric enzyme. The chimera (CtGH1-L1-CtGH5-F194A) expressed as a soluble protein using E. coli BL-21cells displaying 3- to 5-fold higher catalytic efficiency for endoglucanase and β-glucosidase activities. TLC analysis of hydrolysed product of CMC by chimera 1 revealed glucose as final product confirming both β-1,4-endoglucanase and β-1,4-glucosidase activities, while the products of CtGH5-F194A were cellobiose and cello-oligosaccharides. Protein melting studies of CtGH5-F194A showed melting temperature (Tm), 68 °C and of CtGH1, 79 °C, whereas, chimera showed 78 °C. The improved structural integrity, thermostability and enhanced bi-functional enzyme activities of chimera makes it potentially useful for industrial application in converting biomass to glucose and thus bioethanol.
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Affiliation(s)
- Priyanka Nath
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India; DBT PAN-IIT Center for Bioenergy, Indian Institute of Technology Guwahati, India
| | - Arun Dhillon
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Krishan Kumar
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Kedar Sharma
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Sumitha Banu Jamaldheen
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India; Centre for Energy, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Vijayanand Suryakant Moholkar
- Centre for Energy, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India; DBT PAN-IIT Center for Bioenergy, Indian Institute of Technology Guwahati, India; Centre for Energy, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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7
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Sharma K, Fontes CMGA, Najmudin S, Goyal A. Molecular organization and protein stability of the Clostridium thermocellum glucuronoxylan endo-β-1,4-xylanase of family 30 glycoside hydrolase in solution. J Struct Biol 2019; 206:335-344. [PMID: 30959107 DOI: 10.1016/j.jsb.2019.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/02/2019] [Accepted: 04/04/2019] [Indexed: 11/19/2022]
Abstract
Glucuronoxylan-β-1,4-xylanohydrolase from Clostridium thermocellum (CtXynGH30) hydrolyzes β-1,4-xylosidic linkages in 4-O-Methyl-D-glucuronoxylan. CtXynGH30 comprises an N-terminal catalytic domain, CtXyn30A, joined by a typical linker sequence to a family 6 carbohydrate-binding module, termed CtCBM6. ITC, mass spectrometric and enzyme activity analyses of CtXyn30A:CtCBM6 (1:1 M ratio), CtXyn30A and CtXynGH30 showed that the linker peptide plays a key role in connecting and orienting CtXyn30A and CtCBM6 modules resulting in the enhanced activity of CtXynGH30. To visualize the disposition of the two protein domains of CtXynGH30, SAXS analysis revealed that CtXynGH30 is monomeric and has a boot-shaped molecular envelope in solution with a Dmax of 18 nm and Rg of 3.6 nm. Kratky plot displayed the protein in a fully folded and flexible state. The ab initio derived dummy atom model of CtXynGH30 superposed well with the modelled structure.
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Affiliation(s)
- Kedar Sharma
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Carlos M G A Fontes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Shabir Najmudin
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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8
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Grove TL, Himes PM, Hwang S, Yumerefendi H, Bonanno JB, Kuhlman B, Almo SC, Bowers AA. Structural Insights into Thioether Bond Formation in the Biosynthesis of Sactipeptides. J Am Chem Soc 2017; 139:11734-11744. [PMID: 28704043 PMCID: PMC6443407 DOI: 10.1021/jacs.7b01283] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Sactipeptides are ribosomally synthesized peptides that contain a characteristic thioether bridge (sactionine bond) that is installed posttranslationally and is absolutely required for their antibiotic activity. Sactipeptide biosynthesis requires a unique family of radical SAM enzymes, which contain multiple [4Fe-4S] clusters, to form the requisite thioether bridge between a cysteine and the α-carbon of an opposing amino acid through radical-based chemistry. Here we present the structure of the sactionine bond-forming enzyme CteB, from Clostridium thermocellum ATCC 27405, with both SAM and an N-terminal fragment of its peptidyl-substrate at 2.04 Å resolution. CteB has the (β/α)6-TIM barrel fold that is characteristic of radical SAM enzymes, as well as a C-terminal SPASM domain that contains two auxiliary [4Fe-4S] clusters. Importantly, one [4Fe-4S] cluster in the SPASM domain exhibits an open coordination site in absence of peptide substrate, which is coordinated by a peptidyl-cysteine residue in the bound state. The crystal structure of CteB also reveals an accessory N-terminal domain that has high structural similarity to a recently discovered motif present in several enzymes that act on ribosomally synthesized and post-translationally modified peptides (RiPPs), known as a RiPP precursor peptide recognition element (RRE). This crystal structure is the first of a sactionine bond forming enzyme and sheds light on structures and mechanisms of other members of this class such as AlbA or ThnB.
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Affiliation(s)
- Tyler L. Grove
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Paul M. Himes
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
| | - Sungwon Hwang
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
| | - Hayretin Yumerefendi
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jeffrey B. Bonanno
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Steven C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Albert A Bowers
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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9
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Affiliation(s)
- Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100, Israel
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10
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Xu Q, Resch MG, Podkaminer K, Yang S, Baker JO, Donohoe BS, Wilson C, Klingeman DM, Olson DG, Decker SR, Giannone RJ, Hettich RL, Brown SD, Lynd LR, Bayer EA, Himmel ME, Bomble YJ. Dramatic performance of Clostridium thermocellum explained by its wide range of cellulase modalities. Sci Adv 2016; 2:e1501254. [PMID: 26989779 PMCID: PMC4788478 DOI: 10.1126/sciadv.1501254] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/30/2015] [Indexed: 05/18/2023]
Abstract
Clostridium thermocellum is the most efficient microorganism for solubilizing lignocellulosic biomass known to date. Its high cellulose digestion capability is attributed to efficient cellulases consisting of both a free-enzyme system and a tethered cellulosomal system wherein carbohydrate active enzymes (CAZymes) are organized by primary and secondary scaffoldin proteins to generate large protein complexes attached to the bacterial cell wall. This study demonstrates that C. thermocellum also uses a type of cellulosomal system not bound to the bacterial cell wall, called the "cell-free" cellulosomal system. The cell-free cellulosome complex can be seen as a "long range cellulosome" because it can diffuse away from the cell and degrade polysaccharide substrates remotely from the bacterial cell. The contribution of these two types of cellulosomal systems in C. thermocellum was elucidated by characterization of mutants with different combinations of scaffoldin gene deletions. The primary scaffoldin, CipA, was found to play the most important role in cellulose degradation by C. thermocellum, whereas the secondary scaffoldins have less important roles. Additionally, the distinct and efficient mode of action of the C. thermocellum exoproteome, wherein the cellulosomes splay or divide biomass particles, changes when either the primary or secondary scaffolds are removed, showing that the intact wild-type cellulosomal system is necessary for this essential mode of action. This new transcriptional and proteomic evidence shows that a functional primary scaffoldin plays a more important role compared to secondary scaffoldins in the proper regulation of CAZyme genes, cellodextrin transport, and other cellular functions.
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Affiliation(s)
- Qi Xu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
| | - Michael G. Resch
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Kara Podkaminer
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
| | - Shihui Yang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - John O. Baker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
| | - Bryon S. Donohoe
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
| | - Charlotte Wilson
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Dawn M. Klingeman
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Daniel G. Olson
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
| | - Stephen R. Decker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
| | - Richard J. Giannone
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Robert L. Hettich
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Steven D. Brown
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Lee R. Lynd
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
| | | | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
- BioEnergy Science Center, Oak Ridge, TN 37831, USA
- Corresponding author. E-mail:
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11
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Thompson RA, Layton DS, Guss AM, Olson DG, Lynd LR, Trinh CT. Elucidating central metabolic redox obstacles hindering ethanol production in Clostridium thermocellum. Metab Eng 2015; 32:207-219. [PMID: 26497628 DOI: 10.1016/j.ymben.2015.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 10/08/2015] [Accepted: 10/12/2015] [Indexed: 01/24/2023]
Abstract
Clostridium thermocellum is an anaerobic, Gram-positive, thermophilic bacterium that has generated great interest due to its ability to ferment lignocellulosic biomass to ethanol. However, ethanol production is low due to the complex and poorly understood branched metabolism of C. thermocellum, and in some cases overflow metabolism as well. In this work, we developed a predictive stoichiometric metabolic model for C. thermocellum which incorporates the current state of understanding, with particular attention to cofactor specificity in the atypical glycolytic enzymes and the complex energy, redox, and fermentative pathways with the goal of aiding metabolic engineering efforts. We validated the model's capability to encompass experimentally observed phenotypes for the parent strain and derived mutants designed for significant perturbation of redox and energy pathways. Metabolic flux distributions revealed significant alterations in key metabolic branch points (e.g., phosphoenol pyruvate, pyruvate, acetyl-CoA, and cofactor nodes) in engineered strains for channeling electron and carbon fluxes for enhanced ethanol synthesis, with the best performing strain doubling ethanol yield and titer compared to the parent strain. In silico predictions of a redox-imbalanced genotype incapable of growth were confirmed in vivo, and a mutant strain was used as a platform to probe redox bottlenecks in the central metabolism that hinder efficient ethanol production. The results highlight the robustness of the redox metabolism of C. thermocellum and the necessity of streamlined electron flux from reduced ferredoxin to NAD(P)H for high ethanol production. The model was further used to design a metabolic engineering strategy to phenotypically constrain C. thermocellum to achieve high ethanol yields while requiring minimal genetic manipulations. The model can be applied to design C. thermocellum as a platform microbe for consolidated bioprocessing to produce ethanol and other reduced metabolites.
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Affiliation(s)
- R Adam Thompson
- Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville and Oak Ridge National Laboratory, Oak Ridge, TN, USA; BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Donovan S Layton
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Adam M Guss
- Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville and Oak Ridge National Laboratory, Oak Ridge, TN, USA; BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Biosciecnes Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Daniel G Olson
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Lee R Lynd
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Cong T Trinh
- Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville and Oak Ridge National Laboratory, Oak Ridge, TN, USA; BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN, USA.
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12
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Stern J, Kahn A, Vazana Y, Shamshoum M, Moraïs S, Lamed R, Bayer EA. Significance of relative position of cellulases in designer cellulosomes for optimized cellulolysis. PLoS One 2015; 10:e0127326. [PMID: 26024227 PMCID: PMC4449128 DOI: 10.1371/journal.pone.0127326] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/13/2015] [Indexed: 11/23/2022] Open
Abstract
Degradation of cellulose is of major interest in the quest for alternative sources of renewable energy, for its positive effects on environment and ecology, and for use in advanced biotechnological applications. Due to its microcrystalline organization, celluose is extremely difficult to degrade, although numerous microbes have evolved that produce the appropriate enzymes. The most efficient known natural cellulolytic system is produced by anaerobic bacteria, such as C. thermocellum, that possess a multi-enzymatic complex termed the cellulosome. Our laboratory has devised and developed the designer cellulosome concept, which consists of chimaeric scaffoldins for controlled incorporation of recombinant polysaccharide-degrading enzymes. Recently, we reported the creation of a combinatorial library of four cellulosomal modules comprising a basic chimaeric scaffoldin, i.e., a CBM and 3 divergent cohesin modules. Here, we employed selected members of this library to determine whether the position of defined cellulolytic enzymes is important for optimized degradation of a microcrystalline cellulosic substrate. For this purpose, 10 chimaeric scaffoldins were used for incorporation of three recombinant Thermobifida fusca enzymes: the processive endoglucanase Cel9A, endoglucanase Cel5A and exoglucanase Cel48A. In addition, we examined whether the characteristic properties of the T. fusca enzymes as designer cellulosome components are unique to this bacterium by replacing them with parallel enzymes from Clostridium thermocellum. The results support the contention that for a given set of cellulosomal enzymes, their relative position within a scaffoldin can be critical for optimal degradation of microcrystaline cellulosic substrates.
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Affiliation(s)
- Johanna Stern
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Amaranta Kahn
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Yael Vazana
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Melina Shamshoum
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Sarah Moraïs
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Edward A. Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
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13
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Chakraborty S, Fernandes VO, Dias FMV, Prates JAM, Ferreira LMA, Fontes CMGA, Goyal A, Centeno MSJ. Role of pectinolytic enzymes identified in Clostridium thermocellum cellulosome. PLoS One 2015; 10:e0116787. [PMID: 25658912 PMCID: PMC4319962 DOI: 10.1371/journal.pone.0116787] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/09/2014] [Indexed: 11/30/2022] Open
Abstract
The cloning, expression and characterization of three cellulosomal pectinolytic enzymes viz., two variants of PL1 (PL1A and PL1B) and PL9 from Clostridium thermocellum was carried out. The comparison of the primary sequences of PL1A, PL1B and PL9 revealed that these proteins displayed considerable sequence similarities with family 1 and 9 polysaccharide lyases, respectively. PL1A, PL1B and PL9 are the putative catalytic domains of protein sequence ABN54148.1 and ABN53381.1 respectively. These two protein sequences also contain putative carbohydrate binding module (CBM) and type-I dockerin. The associated putative CBM of PL1A showed strong homology with family 6 CBMs while those of PL1B and PL9 showed homology with family 35 CBMs. Recombinant derivatives of these three enzymes showed molecular masses of approximately 34 kDa, 40 kDa and 32 kDa for PL1A, PL1B and PL9, respectively. PL1A, PL1B and PL9 displayed high activity toward polygalacturonic acid and pectin (up to 55% methyl-esterified) from citrus fruits. However, PL1B showed relatively higher activity towards 55% and 85% methyl-esterified pectin (citrus). PL1A and PL9 showed higher activity on rhamnogalacturonan than PL1B. Both PL1A and PL9 displayed maximum activity at pH 8.5 with optimum temperature of 50°C and 60°C respectively. PL1B achieved highest activity at pH 9.8, under an optimum temperature of 50°C. PL1A, PL1B and PL9 all produced two or more unsaturated galacturonates from pectic substrates as displayed by TLC analysis confirming that they are endo-pectate lyase belonging to family 1 and 9, respectively. This report reveals that pectinolytic activity displayed by Clostridium thermocellum cellulosome is coordinated by a sub-set of at least three multi-modular enzymes.
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Affiliation(s)
- Soumyadeep Chakraborty
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Vania O. Fernandes
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Fernando M. V. Dias
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Jose A. M. Prates
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Luis M. A. Ferreira
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | | | - Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
- * E-mail: (AG); (MSJC)
| | - Maria S. J. Centeno
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (AG); (MSJC)
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14
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Kislitsyn YA, Samygina VR, Dvortsov IA, Lunina NA, Kuranova IP, Velikodvorskaya GA. Crystallization and preliminary X-ray diffraction studies of the family 54 carbohydrate-binding module from laminarinase (β-1,3-glucanase) Lic16A of Clostridium thermocellum. Acta Crystallogr F Struct Biol Commun 2015; 71:217-20. [PMID: 25664799 PMCID: PMC4321479 DOI: 10.1107/s2053230x15000539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 01/11/2015] [Indexed: 11/11/2022] Open
Abstract
The crystallization and preliminary X-ray diffraction analysis of the carbohydrate-binding module (CBM) from laminarinase Lic16A of the hyperthermophilic anaerobic bacterium Clostridium thermocellum (ctCBM54) are reported. Recombinant ctCBM54 was prepared using an Escherichia coli/pQE30 overexpression system and was crystallized by the hanging-drop vapour-diffusion method. X-ray diffraction data were collected to 2.1 Å resolution using synchrotron radiation. The crystals belonged to space group P6322, with unit-cell parameters a = b = 130.15, c = 131.05 Å. The three-dimensional structure of ctCBM54 will provide valuable information about the structure-function relation of the laminarinase Lic16A and will allow the exploitation of this binding module in biotechnological applications.
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Affiliation(s)
- Yury A. Kislitsyn
- A. V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky Prospect 59, Moscow 117333, Russian Federation
| | - Valeriya R. Samygina
- A. V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky Prospect 59, Moscow 117333, Russian Federation
| | - Igor A. Dvortsov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Square 2, Moscow 123182, Russian Federation
| | - Nataliya A. Lunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Square 2, Moscow 123182, Russian Federation
| | - Inna P. Kuranova
- A. V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninsky Prospect 59, Moscow 117333, Russian Federation
| | - Galina A. Velikodvorskaya
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Square 2, Moscow 123182, Russian Federation
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15
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Gupta A, Das SP, Ghosh A, Choudhary R, Das D, Goyal A. Bioethanol production from hemicellulose rich Populus nigra involving recombinant hemicellulases from Clostridium thermocellum. Bioresour Technol 2014; 165:205-13. [PMID: 24767793 DOI: 10.1016/j.biortech.2014.03.132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/22/2014] [Accepted: 03/24/2014] [Indexed: 05/11/2023]
Abstract
Bioethanol was produced from poplar leafy biomass rich in hemicelluloses content involving recombinant Clostridium thermocellum hemicellulases and pentose sugar utilizing Candida shehatae. FT-IR analysis revealed effective AFEX pretreatment of poplar leaves. Repetitive batch strategy yielded ∼1.5-fold rise in cell biomass and specific activity of both, acetylxylanesterase (Axe) and GH43 hemicellulase. TLC and HPAEC exhibited xylose and arabinose release from hydrolyzed biomass. SSF trial with 1% (wv(-1)) pretreated poplar and mixed enzymes showed ∼1.5-fold higher ethanol titre as compared with SHF. The shake flask SSF with 5% (wv(-1)) pretreated poplar furnished 4.56 and 5.43gL(-1) ethanol with Axe and mixed enzymes, respectively. Whereas, bioreactor scale-up exhibited ∼1.25-fold increase in ethanol titres (5.68, 6.75gL(-1)) as compared with shake flask with an yield of 0.295 (gg(-1)) and 0.351 (gg(-1)), respectively with Axe and mixed enzymes.
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Affiliation(s)
- Ashutosh Gupta
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Saprativ P Das
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Arabinda Ghosh
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Rajan Choudhary
- Department of Biotechnology, National Institute of Technology Durgapur, Durgapur 713209, West Bengal, India
| | - Debasish Das
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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16
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Costa M, Fernandes VO, Ribeiro T, Serrano L, Cardoso V, Santos H, Lordelo M, Ferreira LMA, Fontes CMGA. Construction of GH16 β-glucanase mini-cellulosomes to improve the nutritive value of barley-based diets for broilers. J Agric Food Chem 2014; 62:7496-7506. [PMID: 25010714 DOI: 10.1021/jf502157y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Anaerobic cellulolytic bacteria organize a comprehensive range of cellulases and hemicellulases in high molecular weight multienzyme complexes termed cellulosomes. Integration of cellulosomal components occurs via highly ordered protein-protein interactions between cohesins and dockerins. This paper reports the production of mini-cellulosomes containing one (GH16-1C) or three (GH16-3C) copies of Clostridium thermocellum glucanase 16A (CtGlc16A). Barley β-1,3-1,4-glucans are known to be antinutritive for monogastric animals, particularly for poultry. GH16-1C and GH16-3C were used to supplement barley-based diets for broilers. The data revealed that the two mini-cellulosomes effectively improved the nutritive value of barley-based diets for broilers. Analysis of mini-cellulosome molecular integrity revealed that linker sequences separating protein domains in scaffoldins and cellulosomal catalytic units are highly susceptible to proteolytic attack in vivo. The data suggest that linker protection could result in further improvements in enzyme efficacy to improve the nutritive value of barley-based diets for monogastric animals.
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Affiliation(s)
- Mónica Costa
- CIISA-Faculdade de Medicina Veterinária, Universidade de Lisboa , Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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17
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Zhang L, Zhao P, Chen CC, Huang CH, Ko TP, Zheng Y, Guo RT. Preliminary X-ray diffraction analysis of a thermophilic β-1,3-1,4-glucanase from Clostridium thermocellum. Acta Crystallogr F Struct Biol Commun 2014; 70:946-8. [PMID: 25005095 PMCID: PMC4089538 DOI: 10.1107/s2053230x14009376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/25/2014] [Indexed: 11/10/2022] Open
Abstract
β-1,3-1,4-Glucanases catalyze the specific hydrolysis of internal β-1,4-glycosidic bonds adjacent to the 3-O-substituted glucose residues in mixed-linked β-glucans. The thermophilic glycoside hydrolase CtGlu16A from Clostridium thermocellum exhibits superior thermal profiles, high specific activity and broad pH adaptability. Here, the catalytic domain of CtGlu16A was expressed in Escherichia coli, purified and crystallized in the trigonal space group P3121, with unit-cell parameters a=b=74.5, c=182.9 Å, by the sitting-drop vapour-diffusion method and diffracted to 1.95 Å resolution. The crystal contains two protein molecules in an asymmetric unit. Further structural determination and refinement are in progress.
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Affiliation(s)
- Lilan Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, People’s Republic of China
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, People’s Republic of China
| | - Puya Zhao
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, People’s Republic of China
| | - Chun-Chi Chen
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, People’s Republic of China
| | - Chun-Hsiang Huang
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, People’s Republic of China
| | - Tzu-Ping Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Yingying Zheng
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, People’s Republic of China
| | - Rey-Ting Guo
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Science, Tianjin 300308, People’s Republic of China
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18
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Goyal A, Ahmed S, Fontes CMGA, Najmudin S. Crystallization and preliminary X-ray crystallographic analysis of a novel α-L-arabinofuranosidase (CtGH43) from Clostridium thermocellum ATCC 27405. Acta Crystallogr F Struct Biol Commun 2014; 70:616-8. [PMID: 24817722 PMCID: PMC4014331 DOI: 10.1107/s2053230x14006402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/22/2014] [Indexed: 11/10/2022] Open
Abstract
The truncated carbohydrate-active enzyme belonging to family 43 glycoside hydrolase from Clostridium thermocellum (CtGH43) is an α-L-arabinofuranosidase that in combination with endoxylanase leads to complete breakdown of L-arabinosyl-substituted xylans. The recombinant enzyme CtGH43 from C. thermocellum was overexpressed in Escherichia coli and purified by immobilized metal-ion affinity chromatography. The recombinant CtGH43 has a molecular mass of 35.86 kDa. Preliminary structural characterization was carried out on CtGH43 crystallized from different conditions, which gave either cube-shaped or brick-shaped crystals. These diffracted to a resolution of 1.65 Å for the cubic form and 1.1 Å for the monoclinic form. Molecular replacement was used to solve the CtGH43 structure.
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Affiliation(s)
- Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, India
- CIISA–Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Shadab Ahmed
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, India
| | - Carlos M. G. A. Fontes
- CIISA–Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Shabir Najmudin
- CIISA–Faculdade de Medicina Veterinaria, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
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Verma AK, Goyal A. [In silico structural characterization and molecular docking studies of first glucuronoxylan-xylanohydrolase (Xyn30a) from family-30 glycosyl hydrolase (GH30) from Clostridium thermocellum]. Mol Biol (Mosk) 2014; 48:322-332. [PMID: 25850302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
CtXynGH30 is a carbohydrate active modular enzyme and component of cellulosome of Clostridium thermocellum. The full length CtXynGH30 contains an N-terminal catalytic module named as Xyn30A and a family 6 carbohydrate binding module (CBM6) at C-terminuis. Xyn30A was modeled by computer program Modeller9v8 taking crystal structure of XynC from B. subtilis as a template to generate the molecular model. Model refinement was done using energy minimization by implementing steepest descent algorithm with GROMOS96 43al force field. Quality assessment by Ramachandran plot showed that 91% amino acids lie in most favourable region and 9% in additional allowed region. Structural analysis depicted that Xyn30A has a (beta/alpha)8 barrel fold. Ad- ditionally, it had a beta-strand rich structure called 'side beta-structure' attached with main catalytic core. Structural superimposition reflected that Glu136 act as a catalytic acid/base while Glu225 act as a catalytic nucleophile. Multiple sequence alignment showed that these catalytic residues are conserved within the family. The docking results showed that these residues display polar interaction with linear and substituted xylo-oligosaccharides. The binding interaction of ligands depicted that aromatic amino acids Trp81, Tyr139, Trp143, Phe172, His198, Tyr200, Tyr227, Trp264 and Tyr265 create binding site pocket around the active site. We report overall structural feature, conserved active site residues and enzymeligand docking of first glucuronoxylan-xylanohydrolase (Xyn30A) of family 30 glycosyl hydrolase (GH30) from Clostridium thermocellum.
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Chen L, Wang L, Zhang H. [Mics of the Clostridium thermocellum in lignocellulose degradation--a review]. Wei Sheng Wu Xue Bao 2014; 54:121-128. [PMID: 24818461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Clostridium thermocellum ( C. thermocellum ) is the dominant microorganism that can efficiently degrade lignocellulose. Extensive studies were done for secreting the cell surface-bound protein complex known as the cellulosome. C. thermocellum is regulated by carbon sources, reflected in overall multiple cellulase production and in the cellulosomal subunit profile. To produce a cellulosomal protein complex is a dynamic assembly process. In recent years, it becomes a hotspot to study how C. thermocellum senses the insoluble substrate, regulates the secretion of relevant enzymes, and assembles the supramolecular-degradation enzyme complex. This review summarized the research advance in genomics, transcriptomics, proteomics and extracellular carbohydrate-sensing mechanism in C. thermocellum, and analyzed the mechanism and dynamic process of C. thermocellum in lignocellulose degradation.
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Ghosh A, Luís AS, Brás JLA, Fontes CMGA, Goyal A. Thermostable recombinant β-(1→4)-mannanase from C. thermocellum: biochemical characterization and manno-oligosaccharides production. J Agric Food Chem 2013; 61:12333-12344. [PMID: 24224831 DOI: 10.1021/jf403111g] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Functional attributes of a thermostable β-(1→4)-mannanase were investigated from Clostridium thermocellum ATCC 27405. Its sequence comparison the exhibited highest similarity with Man26B of C. thermocellum F1. The full length CtManf and truncated CtManT were cloned in the pET28a(+) vector and expressed in E. coli BL21(DE3) cells, exhibiting 53 kDa and 38 kDa proteins, respectively. On the basis of the substrate specificity and hydrolyzed product profile, CtManf and CtManT were classified as β-(1→4)-mannanase. A 1.5 fold higher activity of both enzymes was observed by Ca(2+) and Mg(2+) salts. Plausible mannanase activity of CtManf was revealed by the classical hydrolysis pattern of carob galactomannan and the release of manno-oligosaccharides. Notably highest protein concentrations of CtManf and CtManT were achieved in tryptone yeast extract (TY) medium, as compared with other defined media. Both CtManf and CtManT displayed stability at 60 and 50 °C, respectively, and Ca(2+) ions imparted higher thermostability, resisting their melting up to 100 °C.
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Affiliation(s)
- Arabinda Ghosh
- Department of Biotechnology, Indian Institute of Technology Guwahati , Guwahati-781 039, Assam, India
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22
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Alahuhta M, Adney WS, Himmel ME, Lunin VV. Structure of Acidothermus cellulolyticus family 74 glycoside hydrolase at 1.82 Å resolution. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1335-8. [PMID: 24316824 PMCID: PMC3855714 DOI: 10.1107/s1744309113030005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/01/2013] [Indexed: 11/11/2022]
Abstract
Here, a 1.82 Å resolution X-ray structure of a glycoside hydrolase family 74 (GH74) enzyme from Acidothermus cellulolyticus is reported. The resulting structure was refined to an R factor of 0.150 and an Rfree of 0.196. Structural analysis shows that five related structures have been reported with a secondary-structure similarity of between 75 and 89%. The five similar structures were all either Clostridium thermocellum or Geotrichum sp. M128 GH74 xyloglucanases. Structural analysis indicates that the A. cellulolyticus GH74 enzyme is an endoxyloglucanase, as it lacks a characteristic loop that blocks one end of the active site in exoxyloglucanases. Superimposition with the C. thermocellum GH74 shows that Asp451 and Asp38 are the catalytic residues.
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Affiliation(s)
- Markus Alahuhta
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - William S. Adney
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Michael E. Himmel
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Vladimir V. Lunin
- BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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Verma AK, Goyal A, Freire F, Bule P, Venditto I, Brás JLA, Santos H, Cardoso V, Bonifácio C, Thompson A, Romão MJ, Prates JAM, Ferreira LMA, Fontes CMGA, Najmudin S. Overexpression, crystallization and preliminary X-ray crystallographic analysis of glucuronoxylan xylanohydrolase (Xyn30A) from Clostridium thermocellum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1440-2. [PMID: 24316849 PMCID: PMC3855739 DOI: 10.1107/s1744309113025050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 09/09/2013] [Indexed: 11/10/2022]
Abstract
The modular carbohydrate-active enzyme belonging to glycoside hydrolase family 30 (GH30) from Clostridium thermocellum (CtXynGH30) is a cellulosomal protein which plays an important role in plant cell-wall degradation. The full-length CtXynGH30 contains an N-terminal catalytic module (Xyn30A) followed by a family 6 carbohydrate-binding module (CBM6) and a dockerin at the C-terminus. The recombinant protein has a molecular mass of 45 kDa. Preliminary structural characterization was carried out on Xyn30A crystallized in different conditions. All tested crystals belonged to space group P1 with one molecule in the asymmetric unit. Molecular replacement has been used to solve the Xyn30A structure.
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Affiliation(s)
- Anil Kumar Verma
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - Filipe Freire
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Pedro Bule
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Immacolata Venditto
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Joana L. A. Brás
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Helena Santos
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Vânia Cardoso
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Cecília Bonifácio
- REQUIMTE–CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Andrew Thompson
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette, France
| | - Maria João Romão
- REQUIMTE–CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - José A. M. Prates
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Luís M. A. Ferreira
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Carlos M. G. A. Fontes
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Shabir Najmudin
- CIISA–Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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Ahmed S, Luis AS, Bras JLA, Ghosh A, Gautam S, Gupta MN, Fontes CMGA, Goyal A. A novel α-L-arabinofuranosidase of family 43 glycoside hydrolase (Ct43Araf) from Clostridium thermocellum. PLoS One 2013; 8:e73575. [PMID: 24039988 PMCID: PMC3767815 DOI: 10.1371/journal.pone.0073575] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 07/27/2013] [Indexed: 11/25/2022] Open
Abstract
The study describes a comparative analysis of biochemical, structural and functional properties of two recombinant derivatives from Clostridium thermocellum ATCC 27405 belonging to family 43 glycoside hydrolase. The family 43 glycoside hydrolase encoding α-L-arabinofuranosidase (Ct43Araf) displayed an N-terminal catalytic module CtGH43 (903 bp) followed by two carbohydrate binding modules CtCBM6A (405 bp) and CtCBM6B (402 bp) towards the C-terminal. Ct43Araf and its truncated derivative CtGH43 were cloned in pET-vectors, expressed in Escherichia coli and functionally characterized. The recombinant proteins displayed molecular sizes of 63 kDa (Ct43Araf) and 34 kDa (CtGH43) on SDS-PAGE analysis. Ct43Araf and CtGH43 showed optimal enzyme activities at pH 5.7 and 5.4 and the optimal temperature for both was 50°C. Ct43Araf and CtGH43 showed maximum activity with rye arabinoxylan 4.7 Umg(-1) and 5.0 Umg(-1), respectively, which increased by more than 2-fold in presence of Ca(2+) and Mg(2+) salts. This indicated that the presence of CBMs (CtCBM6A and CtCBM6B) did not have any effect on the enzyme activity. The thin layer chromatography and high pressure anion exchange chromatography analysis of Ct43Araf hydrolysed arabinoxylans (rye and wheat) and oat spelt xylan confirmed the release of L-arabinose. This is the first report of α-L-arabinofuranosidase from C. thermocellum having the capacity to degrade both p-nitrophenol-α-L-arabinofuranoside and p-nitrophenol-α-L-arabinopyranoside. The protein melting curves of Ct43Araf and CtGH43 demonstrated that CtGH43 and CBMs melt independently. The presence of Ca(2+) ions imparted thermal stability to both the enzymes. The circular dichroism analysis of CtGH43 showed 48% β-sheets, 49% random coils but only 3% α-helices.
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Affiliation(s)
- Shadab Ahmed
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Ana Sofia Luis
- CIISA-Faculdade de MedicinaVeterinaria, Avenida da Universidade Técnica, Lisbon, Portugal
| | - Joana L. A. Bras
- CIISA-Faculdade de MedicinaVeterinaria, Avenida da Universidade Técnica, Lisbon, Portugal
| | - Arabinda Ghosh
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Saurabh Gautam
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
| | - Munishwar N. Gupta
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
| | - Carlos M. G. A. Fontes
- CIISA-Faculdade de MedicinaVeterinaria, Avenida da Universidade Técnica, Lisbon, Portugal
| | - Arun Goyal
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
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Abstract
Ribose-5-phosphate isomerase (Rpi) catalyzes the interconversion of D-ribose-5-phosphate and D-ribulose-5-phosphate and plays an essential role in the pentose phosphate pathway and the Calvin cycle of photosynthesis. RpiB, one of the two isoforms of Rpi, is also a potential drug target for some pathogenic bacteria. Clostridium thermocellum ribose-5-phosphate isomerase (CtRpi), belonging to the RpiB family, has recently been employed in the industrial production of rare sugars because of its fast reaction kinetics and narrow substrate specificity. It is known that this enzyme adopts a proton transfer mechanism. It was suggested that the deprotonated Cys65 attracts the proton at C2 of the substrate to initiate the isomerization reaction, and this step is the rate-limiting step. However the elaborate catalytic mechanism is still unclear. We have performed quantum mechanical/molecular mechanical simulations of this rate-limiting step of the reaction catalyzed by CtRpi with the substrate D-ribose. Our results demonstrate that the deprotonated Cys65 is not a stable reactant. Instead, our calculations revealed a concerted proton-transfer mechanism: Asp8, a highly conserved residue in the RpiB family, performs as the base to abstract the proton at Cys65 and Cys65 in turn abstracting the proton of the D-ribose simultaneously. Moreover, we found Thr67 cannot catalyze the proton transfer from O2 to O1 of the D-ribose alone. Water molecule(s) may assist this proton transfer with Thr67. Our findings lead to a clear understanding of the catalysis mechanism of the RpiB family and should guide experiments to increase the catalysis efficiency. This study also highlights the importance of initial protonation states of cysteines.
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Affiliation(s)
- Jun Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Weitao Yang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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26
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Abstract
Cell-free biosystems comprised of synthetic enzymatic pathways would be a promising biomanufacturing platform due to several advantages, such as high product yield, fast reaction rate, easy control and access, and so on. However, it was essential to produce (purified) enzymes at low costs and stabilize them for a long time so to decrease biocatalyst costs. We studied the stability of the four recombinant enzyme mixtures, all of which originated from thermophilic microorganisms: triosephosphate isomerase (TIM) from Thermus thermophiles, fructose bisphosphate aldolase (ALD) from Thermotoga maritima, fructose bisphosphatase (FBP) from T. maritima, and phosphoglucose isomerase (PGI) from Clostridium thermocellum. It was found that TIM and ALD were very stable at evaluated temperature so that they were purified by heat precipitation followed by gradient ammonia sulfate precipitation. In contrast, PGI was not stable enough for heat treatment. In addition, the stability of a low concentration PGI was enhanced by more than 25 times in the presence of 20 mg/L bovine serum albumin or the other three enzymes. At a practical enzyme loading of 1000 U/L for each enzyme, the half-life time of free PGI was prolong to 433 h in the presence of the other three enzymes, resulting in a great increase in the total turn-over number of PGI to 6.2×109 mole of product per mole of enzyme. This study clearly suggested that the presence of other proteins had a strong synergetic effect on the stabilization of the thermolabile enzyme PGI due to in vitro macromolecular crowding effect. Also, this result could be used to explain why not all enzymes isolated from thermophilic microorganisms are stable in vitro because of a lack of the macromolecular crowding environment.
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Affiliation(s)
- Suwan Myung
- Biological Systems Engineering Department, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, United States of America
- Institute for Critical Technology and Applied Science (ICTAS), Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Y-H Percival Zhang
- Biological Systems Engineering Department, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, United States of America
- Institute for Critical Technology and Applied Science (ICTAS), Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- Cell Free Bioinnovations Inc., Blacksburg, Virginia, United States of America
- Gate Fuels Inc., Blacksburg, Virginia, United States of America
- * E-mail:
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27
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Vaithanomsat P, Kosugi A, Apiwatanapiwat W, Thanapase W, Waeonukul R, Tachaapaikoon C, Pason P, Mori Y. Efficient saccharification for non-treated cassava pulp by supplementation of Clostridium thermocellum cellulosome and Thermoanaerobacter brockii β-glucosidase. Bioresour Technol 2013; 132:383-386. [PMID: 23245453 DOI: 10.1016/j.biortech.2012.11.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/02/2012] [Accepted: 11/03/2012] [Indexed: 06/01/2023]
Abstract
Cassava pulp containing 60% starch and 20% cellulose is a promising renewable source for bioethanol. The starch granule was observed to tightly bind cellulose fiber. To achieve an efficient degradation for cassava pulp, saccharification tests without pre-gelatinization treatment were carried out using combination of commercial α-amylase with cellulosome from Clostridium thermocellum S14 and β-glucosidase (rCglT) from Thermoanaerobacter brockii. The saccharification rate for cassava pulp was shown 59% of dry matter. To obtain maximum saccharification rate, glucoamylase (GA) from C. thermocellum S14 was supplemented to the combination. The result showed gradual increase in the saccharification rate to 74% (dry matter). Supplementation of GA to the combination of commercial α-amylase, cellulosome and rCglT is powerful method for efficient saccharification of cassava pulp without pretreatment.
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Affiliation(s)
- Pilanee Vaithanomsat
- Nanotechnology and Biotechnology Division, Kasetsart Agricultural and Agro-Industrial Product Improvement Institute, Kasetsart University, 50, Ngamwongwan Rd., Bangkok 10900, Thailand.
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28
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Choi HW, Kim NH, Lee YK, Hwang BK. The pepper extracellular xyloglucan-specific endo-β-1,4-glucanase inhibitor protein gene, CaXEGIP1, is required for plant cell death and defense responses. Plant Physiol 2013; 161:384-96. [PMID: 23093361 PMCID: PMC3532269 DOI: 10.1104/pp.112.203828] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/19/2012] [Indexed: 05/19/2023]
Abstract
Plants produce various proteinaceous inhibitors to protect themselves against microbial pathogen attack. A xyloglucan-specific endo-β-1,4-glucanase inhibitor1 gene, CaXEGIP1, was isolated and functionally characterized in pepper (Capsicum annuum) plants. CaXEGIP1 was rapidly and strongly induced in pepper leaves infected with avirulent Xanthomonas campestris pv vesicatoria, and purified CaXEGIP1 protein significantly inhibited the hydrolytic activity of the glycoside hydrolase74 family xyloglucan-specific endo-β-1,4-glucanase from Clostridium thermocellum. Soluble-modified green fluorescent protein-tagged CaXEGIP1 proteins were mainly localized to the apoplast of onion (Allium cepa) epidermal cells. Agrobacterium tumefaciens-mediated overexpression of CaXEGIP1 triggered pathogen-independent, spontaneous cell death in pepper and Nicotiana benthamiana leaves. CaXEGIP1 silencing in pepper conferred enhanced susceptibility to virulent and avirulent X. campestris pv vesicatoria, accompanied by a compromised hypersensitive response and lowered expression of defense-related genes. Overexpression of dexamethasone:CaXEGIP1 in Arabidopsis (Arabidopsis thaliana) enhanced resistance to Hyaloperonospora arabidopsidis infection. Comparative histochemical and proteomic analyses revealed that CaXEGIP1 overexpression induced a spontaneous cell death response and also increased the expression of some defense-related proteins in transgenic Arabidopsis leaves. This response was also accompanied by cell wall thickening and darkening. Together, these results suggest that pathogen-inducible CaXEGIP1 positively regulates cell death-mediated defense responses in plants.
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29
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Cheng F, Sheng J, Dong R, Men Y, Gan L, Shen L. Novel xylanase from a holstein cattle rumen metagenomic library and its application in xylooligosaccharide and ferulic Acid production from wheat straw. J Agric Food Chem 2012; 60:12516-12524. [PMID: 23134352 DOI: 10.1021/jf302337w] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A novel gene fragment containing a xylanase was identified from a Holstein cattle rumen metagenomic library. The novel xylanase (Xyln-SH1) belonged to the glycoside hydrolase family 10 (GH10) and exhibited a maximum of 44% identity to the glycoside hydrolase from Clostridium thermocellum ATCC 27405. Xyln-SH1 was heterologously expressed, purified, and characterized. A high level of activity was obtained under the optimum conditions of pH 6.5 and 40 °C. A substrate utilization study indicated that Xyln-SH1 was cellulase-free and strictly specific to xylan from softwood. The synergistic effects of Xyln-SH1 and feruloyl esterase (FAE-SH1) were observed for the release of xylooligosaccharides (XOS) and ferulic acid (FA) from wheat straw. In addition, a high dose of Xyln-SH1 alone was observed to improve the release of FA from wheat straw. These features suggest that this enzyme has substantial potential to improve biomass degradation and industrial applications.
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Affiliation(s)
- Fansheng Cheng
- College of Food Science and Nutritional Engineering, China Agricultural University , Beijing 100083, China
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30
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Affiliation(s)
- Shi-You Ding
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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31
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Dvortsov IA, Lunina NA, Zverlov VV, Velikodvorskaia GA. [The properties of four C-terminal carbohydrate-binding modules (CBM4) of laminarinase Lic16A of Clostridium thermocellum]. Mol Biol (Mosk) 2012; 46:915-921. [PMID: 23350238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
At the C-terminus of multimodular laminarinase Lic16A Clostridium thermocellum four carbohydrate-binding modules (CBM), belonging to family 4, were found. The isolated CBM - CBM4_1, CBM4_2, CBM4_3, CBM4_4 and the tandem CBM4_(1-4) were obtained. None of the recombinant proteins did have the affinity to soluble beta-1,3-1,4-glucans--laminarin and lihenan--the main specific substrates of Licl6A. All modules, except CBM4_4, had the ability to bind bacterial crystalline cellulose, that was atypical for the family 4 CBMs. We found that all CBMs 4 of Licl6A had affinity for xylan, chitin, beta-glucan from yeast cell wall and Avicel, while CBM4_3 and CBM4_4 had additional affinity to chitosan. The tandem CBM4_(1-4) had the highest affinity to yeast cell wall beta-glucan, avicel and pustulan. The binding constants for these substrates were about 100 times higher than that of the individual modules, suggesting a synergy in the process of absorption to these polysaccharides. This finding helps to explain the evolutionary process of CBM multiplication.
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32
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Gefen G, Anbar M, Morag E, Lamed R, Bayer EA. Enhanced cellulose degradation by targeted integration of a cohesin-fused β-glucosidase into the Clostridium thermocellum cellulosome. Proc Natl Acad Sci U S A 2012; 109:10298-303. [PMID: 22689961 PMCID: PMC3387075 DOI: 10.1073/pnas.1202747109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The conversion of recalcitrant plant-derived cellulosic biomass into biofuels is dependent on highly efficient cellulase systems that produce near-quantitative levels of soluble saccharides. Similar to other fungal and bacterial cellulase systems, the multienzyme cellulosome system of the anaerobic, cellulolytic bacterium Clostridium thermocellum is strongly inhibited by the major end product cellobiose. Cellobiose-induced inhibition can be relieved via its cleavage to noninhibitory glucose by the addition of exogenous noncellulosomal enzyme β-glucosidase; however, because the cellulosome is adsorbed to the insoluble substrate only a fraction of β-glucosidase would be available to the cellulosome. Towards this end, we designed a chimeric cohesin-fused β-glucosidase (BglA-CohII) that binds directly to the cellulosome through an unoccupied dockerin module of its major scaffoldin subunit. The β-glucosidase activity is thus focused at the immediate site of cellobiose production by the cellulosomal enzymes. BglA-CohII was shown to retain cellobiase activity and was readily incorporated into the native cellulosome complex. Surprisingly, it was found that the native C. thermocellum cellulosome exists as a homooligomer and the high-affinity interaction of BglA-CohII with the scaffoldin moiety appears to dissociate the oligomeric state of the cellulosome. Complexation of the cellulosome and BglA-CohII resulted in higher overall degradation of microcrystalline cellulose and pretreated switchgrass compared to the native cellulosome alone or in combination with wild-type BglA in solution. These results demonstrate the effect of enzyme targeting and its potential for enhanced degradation of cellulosic biomass.
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Affiliation(s)
- Gilad Gefen
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michael Anbar
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ely Morag
- Designer Energy Ltd., 2 Bergman Street, Rehovot, Israel; and
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Edward A. Bayer
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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Krauss J, Zverlov VV, Schwarz WH. In vitro reconstitution of the complete Clostridium thermocellum cellulosome and synergistic activity on crystalline cellulose. Appl Environ Microbiol 2012; 78:4301-7. [PMID: 22522677 PMCID: PMC3370548 DOI: 10.1128/aem.07959-11] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/30/2012] [Indexed: 11/20/2022] Open
Abstract
Artificial cellulase complexes active on crystalline cellulose were reconstituted in vitro from a native mix of cellulosomal enzymes and CipA scaffoldin. Enzymes containing dockerin modules for binding to the corresponding cohesin modules were prepared from culture supernatants of a C. thermocellum cipA mutant. They were reassociated to cellulosomes via dockerin-cohesin interaction. Recombinantly produced mini-CipA proteins with one to three cohesins either with or without the carbohydrate-binding module (CBM) and the complete CipA protein were used as the cellulosomal backbone. The binding between cohesins and dockerins occurred spontaneously. The hydrolytic activity against soluble and crystalline cellulosic compounds showed that the composition of the complex does not seem to be dependent on which CipA-derived cohesin was used for reconstitution. Binding did not seem to have an obvious local preference (equal binding to Coh1 and Coh6). The synergism on crystalline cellulose increased with an increasing number of cohesins in the scaffoldin. The in vitro-formed complex showed a 12-fold synergism on the crystalline substrate (compared to the uncomplexed components). The activity of reconstituted cellulosomes with full-size CipA reached 80% of that of native cellulosomes. Complexation on the surface of nanoparticles retained the activity of protein complexes and enhanced their stability. Partial supplementation of the native cellulosome components with three selected recombinant cellulases enhanced the activity on crystalline cellulose and reached that of the native cellulosome. This opens possibilities for in vitro complex reconstitution, which is an important step toward the creation of highly efficient engineered cellulases.
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Affiliation(s)
- Jan Krauss
- Department of Microbiology, Technische Universität München, Freising-Weihenstephan, Germany
| | - Vladimir V. Zverlov
- Department of Microbiology, Technische Universität München, Freising-Weihenstephan, Germany
- Institute of Molecular Genetics, Russian Academy of Science, Moscow, Russia
| | - Wolfgang H. Schwarz
- Department of Microbiology, Technische Universität München, Freising-Weihenstephan, Germany
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34
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Slutzki M, Barak Y, Reshef D, Schueler-Furman O, Lamed R, Bayer EA. Measurements of relative binding of cohesin and dockerin mutants using an advanced ELISA technique for high-affinity interactions. Methods Enzymol 2012; 510:417-28. [PMID: 22608739 DOI: 10.1016/b978-0-12-415931-0.00022-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The cellulosome is a large bacterial extracellular multienzyme complex able to degrade crystalline cellulosic substrates. The complex contains catalytic and noncatalytic subunits, interconnected by high-affinity cohesin-dockerin interactions. In this chapter, we introduce an optimized method for comparative binding among different cohesins or cohesin mutants to the dockerin partner. This assay offers advantages over other methods (such as ELISA, cELIA, SPR, and ITC) for particularly high-affinity binding interactions. In this approach, the high-affinity interaction of interest occurs in the liquid phase during the equilibrated binding step, whereas the interaction with the immobilized phase is used only for detection of the unbound dockerins that remain in the solution phase. Once equilibrium conditions are reached, the change in free energy of binding (ΔΔG(binding)), as well as the affinity constant of mutants, can be estimated against the known affinity constant of the wild-type interaction. In light of the above, we propose this method as a preferred alternative for the relative quantification of high-affinity protein interactions.
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Affiliation(s)
- Michal Slutzki
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
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35
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Abstract
The specificity of cohesin-dockerin interactions is critically important for the assembly of cellulosomal enzymes into the multienzyme cellulolytic complex (cellulosome). In order to investigate the origins of the observed specificity, a variety of selected amino acid positions at the cohesin-dockerin interface can be subjected to mutagenesis, and a library of mutants can be constructed. In this chapter, we describe a protein-protein microarray technique based on the high affinity of a carbohydrate-binding module (CBM), attached to mutant cohesins. Using cellulose-coated glass slides, libraries of mutants can be screened for binding to complementary partners. The advantages of this tool are that crude cell lysate can be used without additional purification, and the microarray can be used for screening both large libraries as initial scanning for "positive" plates, and for small libraries, wherein individual colonies are printed on the slide. Since the time-consuming step of purifying proteins can be circumvented, the approach is also appropriate for providing molecular insight into the multicomponent organization of complex cellulosomes.
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Affiliation(s)
- Michal Slutzki
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
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36
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Brás JLA, Carvalho AL, Viegas A, Najmudin S, Alves VD, Prates JAM, Ferreira LMA, Romão MJ, Gilbert HJ, Fontes CMGA. Escherichia coli expression, purification, crystallization, and structure determination of bacterial cohesin-dockerin complexes. Methods Enzymol 2012; 510:395-415. [PMID: 22608738 DOI: 10.1016/b978-0-12-415931-0.00021-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Cellulosomes are highly efficient nanomachines that play a fundamental role during the anaerobic deconstruction of complex plant cell wall carbohydrates. The assembly of these complex nanomachines results from the very tight binding of repetitive cohesin modules, located in a noncatalytic molecular scaffold, and dockerin domains located at the C-terminus of the enzyme components of the cellulosome. The number of enzymes found in a cellulosome varies but may reach more than 100 catalytic subunits if cellulosomes are further organized in polycellulosomes, through a second type of cohesin-dockerin interaction. Structural studies have revealed how the cohesin-dockerin interaction mediates cellulosome assembly and cell-surface attachment, while retaining the flexibility required to potentiate catalytic synergy within the complex. Methods that might be applied for the production, purification, and structure determination of cohesin-dockerin complexes are described here.
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Affiliation(s)
- Joana L A Brás
- CIISA-Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Lisboa, Portugal
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Abstract
During the past several years, major progress has been accomplished in the production of "designer cellulosomes," artificial enzymatic complexes that were demonstrated to efficiently degrade crystalline cellulose. This progress is part of a global attempt to promote biomass waste solutions and biofuel production. In designer cellulosomes, each enzyme is equipped with a dockerin module that interacts specifically with one of the cohesin modules of the chimeric scaffoldin. Artificial scaffoldins serve as docking backbones and contain a cellulose-specific carbohydrate-binding module that directs the enzymatic complex to the cellulosic substrate, and one or more cohesin modules from different natural cellulosomal species, each exhibiting a different specificity, that allows the specific incorporation of the desired matching dockerin-bearing enzymes. With natural cellulosomal components, the insertion of the enzymes in the scaffold would presumably be random, and we would not be able to control the contents of the resulting artificial cellulosome. There are an increasing number of papers describing the production of designer cellulosomes either in vitro, ex vivo, or in vivo. These types of studies are particularly intricate, and a number of such publications are less meaningful in the final analysis, as important controls are frequently excluded. In this chapter, we hope to give a complete overview of the methodologies essential for designing and examining cellulosome complexes.
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Affiliation(s)
- Yael Vazana
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
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Bianchetti CM, Elsen NL, Fox BG, Phillips GN. Structure of cellobiose phosphorylase from Clostridium thermocellum in complex with phosphate. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1345-9. [PMID: 22102229 PMCID: PMC3212448 DOI: 10.1107/s1744309111032660] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 08/11/2011] [Indexed: 11/10/2022]
Abstract
Clostridium thermocellum is a cellulosome-producing bacterium that is able to efficiently degrade and utilize cellulose as a sole carbon source. Cellobiose phosphorylase (CBP) plays a critical role in cellulose degradation by catalyzing the reversible phosphate-dependent hydrolysis of cellobiose, the major product of cellulose degradation, into α-D-glucose 1-phosphate and D-glucose. CBP from C. thermocellum is a modular enzyme composed of four domains [N-terminal domain, helical linker, (α/α)(6)-barrel domain and C-terminal domain] and is a member of glycoside hydrolase family 94. The 2.4 Å resolution X-ray crystal structure of C. thermocellum CBP reveals the residues involved in coordinating the catalytic phosphate as well as the residues that are likely to be involved in substrate binding and discrimination.
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Affiliation(s)
- Christopher M. Bianchetti
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Nathaniel L. Elsen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian G. Fox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - George N. Phillips
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706, USA
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Brown SD, Guss AM, Karpinets TV, Parks JM, Smolin N, Yang S, Land ML, Klingeman DM, Bhandiwad A, Rodriguez M, Raman B, Shao X, Mielenz JR, Smith JC, Keller M, Lynd LR. Mutant alcohol dehydrogenase leads to improved ethanol tolerance in Clostridium thermocellum. Proc Natl Acad Sci U S A 2011; 108:13752-7. [PMID: 21825121 PMCID: PMC3158198 DOI: 10.1073/pnas.1102444108] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Clostridium thermocellum is a thermophilic, obligately anaerobic, gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. Biochemical assays confirm a complete loss of NADH-dependent activity with concomitant acquisition of NADPH-dependent activity, which likely affects electron flow in the mutant. The simplicity of the genetic basis for the ethanol-tolerant phenotype observed here informs rational engineering of mutant microbial strains for cellulosic ethanol production.
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Affiliation(s)
- Steven D Brown
- Biosciences Division and BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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40
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Brás JLA, Correia MAS, Romão MJ, Prates JAM, Fontes CMGA, Najmudin S. Purification, crystallization and preliminary X-ray characterization of the pentamodular arabinoxylanase CtXyl5A from Clostridium thermocellum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:833-6. [PMID: 21795807 PMCID: PMC3144809 DOI: 10.1107/s1744309111020823] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 05/30/2011] [Indexed: 11/10/2022]
Abstract
The cellulosome, a highly elaborate extracellular multi-enzyme complex of cellulases and hemicellulases, is responsible for the degradation of plant cell walls. The xylanase CtXyl5A (Cthe_2193) is a multimodular arabinoxylanase which is one of the largest components of the Clostridium thermocellum cellulosome. The N-terminal catalytic domain of CtXyl5A, which is a member of glycoside hydrolase family 5 (GH5), is responsible for the hydrolysis of arabinoxylans. Appended after it are three noncatalytic carbohydrate-binding modules (CBMs), which belong to families 6 (CBM6), 13 (CBM13) and 62 (CBM62). In addition, CtXyl5A has a fibronectin type III-like (Fn3) module preceding the CBM62 and a type I dockerin (DOK) module following it which allows the enzyme to be integrated into the cellulosome through binding to a cohesin module of the protein scaffold CipA. Crystals of the pentamodular enzyme without the DOK module at the C-terminus, with the domain architecture CtGH5-CBM6-CBM13-Fn3-CBM62, have been obtained. The structure of this pentamodular xylanase has been determined by molecular replacement to a resolution of 2.64 Å using coordinates of CtGH5-CBM6, Fn3 and CBM62 from the PDB as search models.
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Affiliation(s)
- Joana L. A. Brás
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Márcia A. S. Correia
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- REQUIMTE, Departamento de Química, FCT-UNL, 2829-516 Caparica, Portugal
| | - Maria J. Romão
- REQUIMTE, Departamento de Química, FCT-UNL, 2829-516 Caparica, Portugal
| | - José A. M. Prates
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Carlos M. G. A. Fontes
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Shabir Najmudin
- CIISA – Faculdade de Medicina Veterinária, Universidade Técnica de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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41
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Anderson TD, Robson SA, Jiang XW, Malmirchegini GR, Fierobe HP, Lazazzera BA, Clubb RT. Assembly of minicellulosomes on the surface of Bacillus subtilis. Appl Environ Microbiol 2011; 77:4849-58. [PMID: 21622797 PMCID: PMC3147385 DOI: 10.1128/aem.02599-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 05/13/2011] [Indexed: 11/20/2022] Open
Abstract
To cost-efficiently produce biofuels, new methods are needed to convert lignocellulosic biomass into fermentable sugars. One promising approach is to degrade biomass using cellulosomes, which are surface-displayed multicellulase-containing complexes present in cellulolytic Clostridium and Ruminococcus species. In this study we created cellulolytic strains of Bacillus subtilis that display one or more cellulase enzymes. Proteins containing the appropriate cell wall sorting signal are covalently anchored to the peptidoglycan by coexpressing them with the Bacillus anthracis sortase A (SrtA) transpeptidase. This approach was used to covalently attach the Cel8A endoglucanase from Clostridium thermocellum to the cell wall. In addition, a Cel8A-dockerin fusion protein was anchored on the surface of B. subtilis via noncovalent interactions with a cell wall-attached cohesin module. We also demonstrate that it is possible to assemble multienzyme complexes on the cell surface. A three-enzyme-containing minicellulosome was displayed on the cell surface; it consisted of a cell wall-attached scaffoldin protein noncovalently bound to three cellulase-dockerin fusion proteins that were produced in Escherichia coli. B. subtilis has a robust genetic system and is currently used in a wide range of industrial processes. Thus, grafting larger, more elaborate minicellulosomes onto the surface of B. subtilis may yield cellulolytic bacteria with increased potency that can be used to degrade biomass.
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Affiliation(s)
| | | | | | | | | | - Beth A. Lazazzera
- Molecular Biology Institute
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 611 Charles E. Young Drive, Los Angeles, California 90095-1570
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
- Molecular Biology Institute
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42
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Alahuhta M, Luo Y, Ding SY, Himmel ME, Lunin VV. Structure of CBM4 from Clostridium thermocellum cellulase K. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:527-30. [PMID: 21543854 PMCID: PMC3087633 DOI: 10.1107/s1744309111003307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 01/25/2011] [Indexed: 11/10/2022]
Abstract
Here, a 2.0 Å resolution X-ray structure of Clostridium thermocellum cellulase K family 4 carbohydrate-binding module (CelK CBM4) is reported. The resulting structure was refined to an R factor of 0.212 and an R(free) of 0.274. Structural analysis shows that this new structure is very similar to the previously solved structure of C. thermocellum CbhA CBM4. Most importantly, these data support the previously proposed notion of an extended binding pocket using a novel tryptophan-containing loop that may be highly conserved in clostridial CBM4 proteins.
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Affiliation(s)
- Markus Alahuhta
- BioSciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3305, USA
| | - Yonghua Luo
- BioSciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3305, USA
| | - Shi-You Ding
- BioSciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3305, USA
| | - Michael E. Himmel
- BioSciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3305, USA
| | - Vladimir V. Lunin
- BioSciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3305, USA
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Brás JLA, Cartmell A, Carvalho ALM, Verzé G, Bayer EA, Vazana Y, Correia MAS, Prates JAM, Ratnaparkhe S, Boraston AB, Romão MJ, Fontes CMGA, Gilbert HJ. Structural insights into a unique cellulase fold and mechanism of cellulose hydrolysis. Proc Natl Acad Sci U S A 2011; 108:5237-42. [PMID: 21393568 PMCID: PMC3069175 DOI: 10.1073/pnas.1015006108] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Clostridium thermocellum is a well-characterized cellulose-degrading microorganism. The genome sequence of C. thermocellum encodes a number of proteins that contain type I dockerin domains, which implies that they are components of the cellulose-degrading apparatus, but display no significant sequence similarity to known plant cell wall-degrading enzymes. Here, we report the biochemical properties and crystal structure of one of these proteins, designated CtCel124. The protein was shown to be an endo-acting cellulase that displays a single displacement mechanism and acts in synergy with Cel48S, the major cellulosomal exo-cellulase. The crystal structure of CtCel124 in complex with two cellotriose molecules, determined to 1.5 Å, displays a superhelical fold in which a constellation of α-helices encircle a central helix that houses the catalytic apparatus. The catalytic acid, Glu96, is located at the C-terminus of the central helix, but there is no candidate catalytic base. The substrate-binding cleft can be divided into two discrete topographical domains in which the bound cellotriose molecules display twisted and linear conformations, respectively, suggesting that the enzyme may target the interface between crystalline and disordered regions of cellulose.
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Affiliation(s)
- Joana L. A. Brás
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Alan Cartmell
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712
| | - Ana Luísa M. Carvalho
- Rede de Química e Tecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Genny Verzé
- Rede de Química e Tecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
- Biocrystallography Laboratory, Department of Biotechnology, University of Verona, 37129 Verona, Italy
| | - Edward A. Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100 Israel; and
| | - Yael Vazana
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100 Israel; and
| | - Márcia A. S. Correia
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - José A. M. Prates
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Supriya Ratnaparkhe
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712
| | - Alisdair B. Boraston
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W 3P6
| | - Maria J. Romão
- Rede de Química e Tecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Carlos M. G. A. Fontes
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Harry J. Gilbert
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712
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Jain R, Shuman S. Active site mapping and substrate specificity of bacterial Hen1, a manganese-dependent 3' terminal RNA ribose 2'O-methyltransferase. RNA 2011; 17:429-38. [PMID: 21205839 PMCID: PMC3039143 DOI: 10.1261/rna.2500711] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The RNA methyltransferase Hen1 and the RNA end-healing/sealing enzyme Pnkp comprise an RNA repair system encoded by an operon-like cassette present in bacteria from eight different phyla. Clostridium thermocellum Hen1 (CthHen1) is a manganese-dependent RNA ribose 2'O-methyltransferase that marks the 3' terminal nucleoside of broken RNAs and protects repair junctions from iterative damage by transesterifying endonucleases. Here we used the crystal structure of the homologous plant Hen1 to guide a mutational analysis of CthHen1, the results of which provide new insights to RNA end recognition and catalysis. We illuminated structure-activity relations at eight essential constituents of the active site implicated in binding the 3' dinucleotide of the RNA methyl acceptor (Arg273, Arg414), the manganese cofactor (Glu366, Glu369, His370, His418), and the AdoMet methyl donor (Asp291, Asp316). We investigated the effects of varying the terminal nucleobase, RNA size, RNA content, and RNA secondary structure on methyl acceptor activity. Key findings are as follows. CthHen1 displayed a fourfold preference for guanosine as the terminal nucleoside. RNA size had little impact in the range of 12-24 nucleotides, but activity declined sharply with a 9-mer. CthHen1 was adept at methylating a polynucleotide composed of 23 deoxyribonucleotides and one 3' terminal ribonucleotide, signifying that it has no strict RNA specificity beyond the 3' nucleoside. CthHen1 methylated RNA ends in the context of duplex secondary structures. These properties distinguish bacterial Hen1 from plant and metazoan homologs.
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Affiliation(s)
- Ruchi Jain
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10065, USA
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45
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Bomble YJ, Beckham GT, Matthews JF, Nimlos MR, Himmel ME, Crowley MF. Modeling the self-assembly of the cellulosome enzyme complex. J Biol Chem 2011; 286:5614-23. [PMID: 21098021 PMCID: PMC3037675 DOI: 10.1074/jbc.m110.186031] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/16/2010] [Indexed: 11/06/2022] Open
Abstract
Most bacteria use free enzymes to degrade plant cell walls in nature. However, some bacteria have adopted a different strategy wherein enzymes can either be free or tethered on a protein scaffold forming a complex called a cellulosome. The study of the structure and mechanism of these large macromolecular complexes is an active and ongoing research topic, with the goal of finding ways to improve biomass conversion using cellulosomes. Several mechanisms involved in cellulosome formation remain unknown, including how cellulosomal enzymes assemble on the scaffoldin and what governs the population of cellulosomes created during self-assembly. Here, we present a coarse-grained model to study the self-assembly of cellulosomes. The model captures most of the physical characteristics of three cellulosomal enzymes (Cel5B, CelS, and CbhA) and the scaffoldin (CipA) from Clostridium thermocellum. The protein structures are represented by beads connected by restraints to mimic the flexibility and shapes of these proteins. From a large simulation set, the assembly of cellulosomal enzyme complexes is shown to be dominated by their shape and modularity. The multimodular enzyme, CbhA, binds statistically more frequently to the scaffoldin than CelS or Cel5B. The enhanced binding is attributed to the flexible nature and multimodularity of this enzyme, providing a longer residence time around the scaffoldin. The characterization of the factors influencing the cellulosome assembly process may enable new strategies to create designers cellulosomes.
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Affiliation(s)
- Yannick J Bomble
- Biosciences Center, Colorado School of Mines, Golden, Colorado 80401, USA.
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46
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Lee HL, Chang CK, Teng KH, Liang PH. Construction and characterization of different fusion proteins between cellulases and β-glucosidase to improve glucose production and thermostability. Bioresour Technol 2011; 102:3973-3976. [PMID: 21169014 DOI: 10.1016/j.biortech.2010.11.114] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/19/2010] [Accepted: 11/22/2010] [Indexed: 05/30/2023]
Abstract
A β-glucosidase from Clostridium cellulovorans (CcBG) was fused with one of three different types of cellulases from Clostridium thermocellum, including a cellulosomal endoglucanase CelD (CtCD), a cellulosomal exoglucanase CBHA (CtCA) and a non-cellulosomal endoglucanase Cel9I (CtC9I). Six bifunctional enzymes were constructed with either β-glucosidase or cellulase in the upstream. CtCD-CcBG showed the favorable specific activities on phosphoric acid swollen cellulose (PASC), an amorphous cellulose, with more glucose production (2 folds) and less cellobiose accumulation (3 folds) when compared with mixture of the single enzymes. Moreover, CtCD-CcBG had significantly improved thermal stability with a melting temperature (T(m)) of 10.9°C higher than that of CcBG (54.5°C) based on the CD unfolding experiments. This bifunctional enzyme is thus useful in industrial application to convert cellulose to glucose.
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Affiliation(s)
- Hsiao-Lin Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
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47
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Yi ZL, Pei XQ, Wu ZL. Introduction of glycine and proline residues onto protein surface increases the thermostability of endoglucanase CelA from Clostridium thermocellum. Bioresour Technol 2011; 102:3636-3638. [PMID: 21123051 DOI: 10.1016/j.biortech.2010.11.043] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 11/05/2010] [Accepted: 11/09/2010] [Indexed: 05/30/2023]
Abstract
A saturation mutagenesis library was constructed at the position 329 of the endoglucanase CelA from Clostridium thermocellum based on previous results (Yi and Wu, 2010), and one mutation, S329G, was identified to contribute to the enhanced thermostability. The result inspired a rational design approach focusing on the introduction of Gly or Pro residue onto the protein surface, which led to the identification of two additional beneficial mutations, H194G and S269P. Combination of these three mutations resulted in a mutant with a 10-fold increase in half-life of inactivation (60 min) at 86°C without compromising activity compared with the wild-type. Its reaction temperature for maximum activity increased from 75 to 85°C. The results provide valuable thermostability-related structural information on this thermophilic enzyme.
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Affiliation(s)
- Zhuo-Lin Yi
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
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48
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Jung J, Kim JK, Yeom SJ, Ahn YJ, Oh DK, Kang LW. Crystal structure of Clostridium thermocellum ribose-5-phosphate isomerase B reveals properties critical for fast enzyme kinetics. Appl Microbiol Biotechnol 2011; 90:517-27. [PMID: 21253719 DOI: 10.1007/s00253-011-3095-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/21/2010] [Accepted: 01/03/2011] [Indexed: 11/27/2022]
Abstract
Ribose-5-phosphate isomerase (Rpi) catalyzes the conversion of D-ribose 5-phosphate (R5P) to D-ribulose 5-phosphate, which is an important step in the non-oxidative pathway of the pentose phosphate pathway and the Calvin cycle of photosynthesis. Recently, Rpis have been used to produce valuable rare sugars for industrial purposes. Of the Rpis, D-ribose-5-phosphate isomerase B from Clostridium thermocellum (CtRpi) has the fastest reactions kinetics. While Thermotoga maritime Rpi (TmRpi) has the same substrate specificity as CtRpi, the overall activity of CtRpi is approximately 200-fold higher than that of TmRpi. To understand the structural basis of these kinetic differences, we determined the crystal structures, at 2.1-Å resolution or higher, of CtRpi alone and bound to its substrates, R5P, D-ribose, and D-allose. Structural comparisons of CtRpi and TmRpi showed overall conservation of their structures with two notable differences. First, the volume of the CtRpi substrate binding pocket (SBP) was 20% less than that of the TmRpi SBP. Second, the residues next to the sugar-ring opening catalytic residue (His98) were different. We switched the key residues, involved in SBP shaping or catalysis, between CtRpi and TmRpi by site-directed mutagenesis, and studied the enzyme kinetics of the mutants. We found that tight interactions between the two monomers, narrow SBP width, and the residues near the catalytic residue are all critical for the fast enzyme kinetics of CtRpi.
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Affiliation(s)
- Junho Jung
- Department of Advanced Technology Fusion, Konkuk University, Hwayang dong, Gwangjin-gu, Seoul 143-701, South Korea
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Komakhin RA, Komakhina VV, Miliukova NA, Goldenkova-Pavlova IV, Fadina OA, Zhuchenko AA. [Transgenic tomato plants expressing recA and NLS-recA-licBM3 genes as a model for studying meiotic recombination]. Genetika 2010; 46:1635-1644. [PMID: 21434416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Homologous DNA recombination in eukaryotes is necessary to maintain genome stability and integrity and for correct chromosome segregation and formation of new haplotypes in meiosis. At the same time, genetic determination and nonrandomness of meiotic recombination restrict the introgression of genes and generation of unique genotypes. As one of the approaches to study and induce meiotic recombination in plants, it is recommended to use the recA gene of Escherichia coli. It is shown that the recA and NLS-recA-licBM3 genes have maternal inheritance and are expressed in the progeny of transgenic tomato plants. Plants expressing recA or NLS-recA-licBM3 and containing one T-DNA insertion do not differ in pollen fertility from original nontransgenic forms and can therefore be used for comparative studies of the effect of bacterial recombinases on meiotic recombination between linked genes.
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Fontes CMGA, Ponte PIP, Reis TC, Soares MC, Gama LT, Dias FMV, Ferreira LMA. A family 6 carbohydrate-binding module potentiates the efficiency of a recombinant xylanase used to supplement cereal-based diets for poultry. Br Poult Sci 2010; 45:648-56. [PMID: 15623219 DOI: 10.1080/00071660400006362] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
(1) Cellulases and xylanases display a modular architecture that comprises a catalytic module linked to one or more non-catalytic carbohydrate-binding modules (CBMs). On the basis of primary structure similarity, CBMs have been classified into more than 30 different families. These non-catalytic modules mediate a prolonged and intimate contact of the enzyme with the target substrate, eliciting efficient hydrolysis of the insoluble polysaccharides. (2) Xylanases are very effective in improving the nutritive value of wheat- or rye-based diets for broiler chicks although the role of non-catalytic CBMs in the function of exogenous modular xylanases in vivo remains to be determined. (3) A study was undertaken to investigate the importance of a family 6 CBM in the function of recombinant derivatives of xylanase 11A (Xyn11A) of Clostridium thermocellum used to supplement cereal-based diets for poultry. (4) The data show that birds fed on a wheat-based diet supplemented with the modular xylanase display an increased final body weight when compared with birds receiving Xyn11A catalytic module or birds receiving the enzyme mixture Roxazyme G. (5) Interestingly, the modular xylanase was truncated and transformed into its single domain counterpart on the duodenum of birds fed on the wheat-based diets, most possibly due to the action of pancreatic proteases. (6) Together the data point to the importance of CBMs in the function of feed xylanases and suggest, that in chicken fed on wheat-based diets, the main sites for exogenous enzymes action might be the gastrointestinal (GI) compartments preceding the duodenum, most probably the crop.
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Affiliation(s)
- C M G A Fontes
- CIISA-Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Lisboa, Portugal.
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