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Lai Z, Zhou C, Ma X, Xue Y, Ma Y. Enzymatic characterization of a novel thermostable and alkaline tolerant GH10 xylanase and activity improvement by multiple rational mutagenesis strategies. Int J Biol Macromol 2020; 170:164-177. [PMID: 33352153 DOI: 10.1016/j.ijbiomac.2020.12.137] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 11/15/2022]
Abstract
Thermo-alkaline xylanases are widely applied in paper pulping industry. In this study, a novel thermostable and alkaline tolerant GH10 xylanase (Xyn30Y5) gene from alkaliphilic Bacillus sp. 30Y5 was cloned and the surface-layer homology (SLH) domains truncated enzyme (Xyn30Y5-SLH) was expressed in Escherichia coli. The purified Xyn30Y5-SLH was most active at 70 °C and pH 7.0 and showed the highest specific activity of 349.4 U mg-1. It retained more than 90% activity between pH 6.0 to 9.5 and was stable at pH 6.0-10.0. To improve the activity, 47 mutants were designed based on eight rational strategies and 21 mutants showed higher activity. By combinatorial mutagenesis, the best mutant 3B demonstrated specific activity of 1016.8 U mg-1 with a doubled catalytic efficiency (kcat/Km) and RA601/2h value, accompanied by optimal pH shift to 8.0. The molecular dynamics simulation analysis indicated that the increase of flexibility of α5 helix and loop7 located near to the catalytic residues is likely responsible for its activity improvement. And the decrease of flexibility of the most unstable regions is vital for the thermostablity improvement. This work provided not only a novel thermostable and alkaline tolerant xylanase with industrial application potential but also an effective mutagenesis strategy for xylanase activity improvement.
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Affiliation(s)
- Zhihua Lai
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Cheng Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xiaochen Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanfen Xue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanhe Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; National Engineering Laboratory for Industrial Enzymes, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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2
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Anuar NFSK, Wahab RA, Huyop F, Halim KBA, Hamid AAA. In silico mutation on a mutant lipase from Acinetobacter haemolyticus towards enhancing alkaline stability. J Biomol Struct Dyn 2019; 38:4493-4507. [DOI: 10.1080/07391102.2019.1683074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Nurul Fatin Syamimi Khairul Anuar
- Department of Bioscience, Faculty of Science, Universiti Teknologi Malaysia, Johor, Bahru, Malaysia
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor, Bahru, Malaysia
| | - Roswanira Abdul Wahab
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor, Bahru, Malaysia
- Enzyme Technology and Green Synthesis Research Group, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia
| | - Fahrul Huyop
- Department of Bioscience, Faculty of Science, Universiti Teknologi Malaysia, Johor, Bahru, Malaysia
- Enzyme Technology and Green Synthesis Research Group, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia
| | - Khairul Bariyyah Abd Halim
- Department of Biotechnology, Kuliyyah of Science, International Islamic University Malaysia, Bandar Indera Mahkota Kuantan, Malaysia
| | - Azzmer Azzar Abdul Hamid
- Department of Biotechnology, Kuliyyah of Science, International Islamic University Malaysia, Bandar Indera Mahkota Kuantan, Malaysia
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3
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Effects of mutations of non-catalytic aromatic residues on substrate specificity of Bacillus licheniformis endocellulase cel12A. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.01.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Boonyapakron K, Jaruwat A, Liwnaree B, Nimchua T, Champreda V, Chitnumsub P. Structure-based protein engineering for thermostable and alkaliphilic enhancement of endo-β-1,4-xylanase for applications in pulp bleaching. J Biotechnol 2017; 259:95-102. [DOI: 10.1016/j.jbiotec.2017.07.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/17/2017] [Accepted: 07/28/2017] [Indexed: 10/19/2022]
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5
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Structural comparison, docking and substrate interaction study of modeled endo -1, 4-beta xylanase enzyme of Bacillus brevis. J Mol Graph Model 2017; 74:337-343. [DOI: 10.1016/j.jmgm.2017.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 12/16/2016] [Accepted: 02/21/2017] [Indexed: 11/24/2022]
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6
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Deciphering the factors defining the pH-dependence of a commercial glycoside hydrolase family 8 enzyme. Enzyme Microb Technol 2017; 96:163-169. [DOI: 10.1016/j.enzmictec.2016.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 10/13/2016] [Accepted: 10/17/2016] [Indexed: 01/05/2023]
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7
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Bai W, Cao Y, Liu J, Wang Q, Jia Z. Improvement of alkalophilicity of an alkaline xylanase Xyn11A-LC from Bacillus sp. SN5 by random mutation and Glu135 saturation mutagenesis. BMC Biotechnol 2016; 16:77. [PMID: 27825339 PMCID: PMC5101721 DOI: 10.1186/s12896-016-0310-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/21/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Family 11 alkaline xylanases have great potential economic applications in the pulp and paper industry. In this study, we would improve the alkalophilicity of family 11 alkaline xylanase Xyn11A-LC from Bacillus sp. SN5, for the better application in this field. RESULTS A random mutation library of Xyn11A-LC with about 10,000 clones was constructed by error-prone PCR. One mutant, M52-C10 (V116A and E135V), with improved alkalophilicity was obtained from the library. Site-directed mutation showed that the mutation E135V was responsible for the alkalophilicity of the mutant. The variant E135V shifted the optimum pH of the wild-type enzyme from 7.5 to 8.0. Compared to the relative activities of the wild type enzyme, those of the mutant E135V increased by 17.5, 18.9, 14.3 and 9.5 % at pH 8.5, 9.0, 9.5 and 10.0, respectively. Furthermore, Glu135 saturation mutagenesis showed that the only mutant to have better alkalophilicity than E135V was E135R. The optimal pH of the mutant E135R was 8.5, 1.0 pH units higher than that of the wild-type. In addition, compared to the wild-type enzyme, the mutations E135V and E135R increased the catalytic efficiency (k cat/K m) by 57 and 37 %, respectively. Structural analysis showed that the residue at position 135, located in the eight-residue loop on the protein surface, might improve the alkalophilicity and catalytic activity by the elimination of the negative charge and the formation of salt-bridge. CONCLUSIONS Mutants E135V and E135R with improved alkalophilicity were obtained by directed evolution and site saturation mutagenesis. The residue at position 135 in the eight-residue loop on the protein surface was found to play an important role in the pH activity profile of family 11 xylanases. This study provided alkalophilic mutants for application in bleaching process, and it was also helpful to understand the alkaline adaptation mechanism of family 11 xylanases.
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Affiliation(s)
- Wenqin Bai
- Department of Strategic and Integrative Research, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 300308, Tianjin, China. .,College of Life Science, Shanxi Normal University, Linfen, 041004, China.
| | - Yufan Cao
- Department of Strategic and Integrative Research, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 300308, Tianjin, China.,College of Life Science, Shanxi Normal University, Linfen, 041004, China
| | - Jun Liu
- Department of Strategic and Integrative Research, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 300308, Tianjin, China.,College of Life Science, Shanxi Normal University, Linfen, 041004, China
| | - Qinhong Wang
- Department of Strategic and Integrative Research, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 300308, Tianjin, China
| | - Zhenhu Jia
- College of Life Science, Shanxi Normal University, Linfen, 041004, China.
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8
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Ma F, Xie Y, Luo M, Wang S, Hu Y, Liu Y, Feng Y, Yang GY. Sequence homolog-based molecular engineering for shifting the enzymatic pH optimum. Synth Syst Biotechnol 2016; 1:195-206. [PMID: 29062943 PMCID: PMC5640797 DOI: 10.1016/j.synbio.2016.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 10/29/2022] Open
Abstract
Cell-free synthetic biology system organizes multiple enzymes (parts) from different sources to implement unnatural catalytic functions. Highly adaption between the catalytic parts is crucial for building up efficient artificial biosynthetic systems. Protein engineering is a powerful technology to tailor various enzymatic properties including catalytic efficiency, substrate specificity, temperature adaptation and even achieve new catalytic functions. However, altering enzymatic pH optimum still remains a challenging task. In this study, we proposed a novel sequence homolog-based protein engineering strategy for shifting the enzymatic pH optimum based on statistical analyses of sequence-function relationship data of enzyme family. By two statistical procedures, artificial neural networks (ANNs) and least absolute shrinkage and selection operator (Lasso), five amino acids in GH11 xylanase family were identified to be related to the evolution of enzymatic pH optimum. Site-directed mutagenesis of a thermophilic xylanase from Caldicellulosiruptor bescii revealed that four out of five mutations could alter the enzymatic pH optima toward acidic condition without compromising the catalytic activity and thermostability. Combination of the positive mutants resulted in the best mutant M31 that decreased its pH optimum for 1.5 units and showed increased catalytic activity at pH < 5.0 compared to the wild-type enzyme. Structure analysis revealed that all the mutations are distant from the active center, which may be difficult to be identified by conventional rational design strategy. Interestingly, the four mutation sites are clustered at a certain region of the enzyme, suggesting a potential "hot zone" for regulating the pH optima of xylanases. This study provides an efficient method of modulating enzymatic pH optima based on statistical sequence analyses, which can facilitate the design and optimization of suitable catalytic parts for the construction of complicated cell-free synthetic biology systems.
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Affiliation(s)
- Fuqiang Ma
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Yuan Xie
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Manjie Luo
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Shuhao Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - You Hu
- School of Statistics, East China Normal University, Shanghai 200241, China
| | - Yukun Liu
- School of Statistics, East China Normal University, Shanghai 200241, China
| | - Yan Feng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Guang-Yu Yang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.,Shanghai Collaborative Innovation Center for Biomanufacturing (SCICB), East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
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9
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Cheng YS, Chen CC, Huang JW, Ko TP, Huang Z, Guo RT. Improving the catalytic performance of a GH11 xylanase by rational protein engineering. Appl Microbiol Biotechnol 2015; 99:9503-10. [DOI: 10.1007/s00253-015-6712-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/18/2015] [Accepted: 05/21/2015] [Indexed: 11/28/2022]
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10
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Li H, Turunen O. Effect of acidic amino acids engineered into the active site cleft ofThermopolyspora flexuosaGH11 xylanase. Biotechnol Appl Biochem 2015; 62:433-40. [DOI: 10.1002/bab.1288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/02/2014] [Indexed: 11/07/2022]
Affiliation(s)
- He Li
- Department of Biotechnology and Chemical Technology; School of Chemical Technology; Aalto University; Aalto 00076 Finland
| | - Ossi Turunen
- Department of Biotechnology and Chemical Technology; School of Chemical Technology; Aalto University; Aalto 00076 Finland
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11
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Chen CC, Ko TP, Huang JW, Guo RT. Heat- and Alkaline-Stable Xylanases: Application, Protein Structure and Engineering. CHEMBIOENG REVIEWS 2015. [DOI: 10.1002/cben.201400035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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12
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Driss D, Bhiri F, Siela M, Ghorbel R, Chaabouni SE. Purification and Properties of a Thermostable Xylanase GH 11 from Penicillium occitanis Pol6. Appl Biochem Biotechnol 2012; 168:851-63. [DOI: 10.1007/s12010-012-9824-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 08/01/2012] [Indexed: 10/28/2022]
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13
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Cloning and constitutive expression of His-tagged xylanase GH 11 from Penicillium occitanis Pol6 in Pichia pastoris X33: Purification and characterization. Protein Expr Purif 2012; 83:8-14. [DOI: 10.1016/j.pep.2012.02.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/18/2012] [Accepted: 02/20/2012] [Indexed: 11/18/2022]
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14
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Cheng YS, Ko TP, Huang JW, Wu TH, Lin CY, Luo W, Li Q, Ma Y, Huang CH, Wang AHJ, Liu JR, Guo RT. Enhanced activity of Thermotoga maritima cellulase 12A by mutating a unique surface loop. Appl Microbiol Biotechnol 2011; 95:661-9. [PMID: 22170108 DOI: 10.1007/s00253-011-3791-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 11/20/2011] [Accepted: 11/23/2011] [Indexed: 11/24/2022]
Abstract
Cellulase 12A from Thermotoga maritima (TmCel12A) is a hyperthermostable β-1,4-endoglucanase. We recently determined the crystal structures of TmCel12A and its complexes with oligosaccharides. Here, by using site-directed mutagenesis, the role played by Arg60 and Tyr61 in a unique surface loop of TmCel12A was investigated. The results are consistent with the previously observed hydrogen bonding and stacking interactions between these two residues and the substrate. Interestingly, the mutant Y61G had the highest activity when compared with the wild-type enzyme and the other mutants. It also shows a wider range of working temperatures than does the wild type, along with retention of the hyperthermostability. The k (cat) and K (m) values of Y61G are both higher than those of the wild type. In conjunction with the crystal structure of Y61G-substrate complex, the kinetic data suggest that the higher endoglucanase activity is probably due to facile dissociation of the cleaved sugar moiety at the reducing end. Additional crystallographic analyses indicate that the insertion and deletion mutations at the Tyr61 site did not affect the overall protein structure, but local perturbations might diminish the substrate-binding strength. It is likely that the catalytic efficiency of TmCel12A is a subtle balance between substrate binding and product release. The activity enhancement by the single mutation of Y61G provides a good example of engineered enzyme for industrial application.
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Affiliation(s)
- Ya-Shan Cheng
- Institute of Biotechnology, National Taiwan University, Taipei, 106, Taiwan
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15
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Paës G, Berrin JG, Beaugrand J. GH11 xylanases: Structure/function/properties relationships and applications. Biotechnol Adv 2011; 30:564-92. [PMID: 22067746 DOI: 10.1016/j.biotechadv.2011.10.003] [Citation(s) in RCA: 281] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 10/06/2011] [Accepted: 10/13/2011] [Indexed: 01/02/2023]
Abstract
For technical, environmental and economical reasons, industrial demands for process-fitted enzymes have evolved drastically in the last decade. Therefore, continuous efforts are made in order to get insights into enzyme structure/function relationships to create improved biocatalysts. Xylanases are hemicellulolytic enzymes, which are responsible for the degradation of the heteroxylans constituting the lignocellulosic plant cell wall. Due to their variety, xylanases have been classified in glycoside hydrolase families GH5, GH8, GH10, GH11, GH30 and GH43 in the CAZy database. In this review, we focus on GH11 family, which is one of the best characterized GH families with bacterial and fungal members considered as true xylanases compared to the other families because of their high substrate specificity. Based on an exhaustive analysis of the sequences and 3D structures available so far, in relation with biochemical properties, we assess biochemical aspects of GH11 xylanases: structure, catalytic machinery, focus on their "thumb" loop of major importance in catalytic efficiency and substrate selectivity, inhibition, stability to pH and temperature. GH11 xylanases have for a long time been used as biotechnological tools in various industrial applications and represent in addition promising candidates for future other uses.
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Affiliation(s)
- Gabriel Paës
- INRA, UMR614 FARE, 2 esplanade Roland-Garros, F-51686 Reims, France.
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16
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Driss D, Bhiri F, Elleuch L, Bouly N, Stals I, Miled N, Blibech M, Ghorbel R, Chaabouni SE. Purification and properties of an extracellular acidophilic endo-1,4-β-xylanase, naturally deleted in the “thumb”, from Penicillium occitanis Pol6. Process Biochem 2011. [DOI: 10.1016/j.procbio.2011.02.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Gibbs M, Reeves R, Hardiman E, Choudhary P, Daniel R, Bergquist P. The activity of family 11 xylanases at alkaline pH. N Biotechnol 2010; 27:795-802. [DOI: 10.1016/j.nbt.2010.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/09/2010] [Indexed: 11/30/2022]
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18
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Structural insights into the acidophilic pH adaptation of a novel endo-1,4-β-xylanase from Scytalidium acidophilum. Biochimie 2010; 92:1407-15. [DOI: 10.1016/j.biochi.2010.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 07/02/2010] [Indexed: 11/22/2022]
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19
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Gibbs MD, Reeves RA, Choudhary PR, Bergquist PL. Alteration of the pH optimum of a family 11 xylanase, XynB6 of Dictyoglomus thermophilum. N Biotechnol 2010; 27:803-9. [PMID: 20601267 DOI: 10.1016/j.nbt.2010.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/13/2010] [Indexed: 10/19/2022]
Abstract
We reported previously that the activities of several glycosyl hydrolase family 11 xylanases claimed to be active under alkaline conditions, were found to have optima in the pH 5-6 range when assayed under optimal conditions. One enzyme, BadX, had enhanced activity at pHs greater than 7 compared to other family 11 xylanases. Gene shuffling between badX and Dictyoglomus thermophilum xynB6 was performed in an attempt to elucidate regions conferring alkaline activity to BadX, and potentially, to increase the alkaline activity of the highly thermophilic XynB6. Segment substitution using degenerate oligonucleotide gene shuffling (DOGS) experiments with combinations of input parental gene fragments from xynB6 and badX was not able to improve the activity of XynB6 at alkaline pH. With one exception, the replacement of a single segment of BadX with the equivalent segment from XynB6 reduced the alkaline activity BadX. The results indicate that it might not be possible to alter significantly the alkaline pH characteristics of family 11 xylanases by one or a few mutations and that family 11 xylanases showing enhanced activity at alkaline pH's require multiple sequence adaptations across the protein.
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Affiliation(s)
- M D Gibbs
- Applimex Systems Pty Ltd., North Ryde, NSW 2109, Australia
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20
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Jordan DB, Wagschal K. Properties and applications of microbial β-D-xylosidases featuring the catalytically efficient enzyme from Selenomonas ruminantium. Appl Microbiol Biotechnol 2010; 86:1647-58. [DOI: 10.1007/s00253-010-2538-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 03/02/2010] [Accepted: 03/03/2010] [Indexed: 11/28/2022]
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21
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Umemoto H, Yazawa R, Takakura J, Yatsunami R, Fukui T, Nakamura S. Analysis of Functional Domains and Improvement of Alkaliphily of an Alkaline Xylanase on the Basis of Its Three-dimensional Structure. J Appl Glycosci (1999) 2010. [DOI: 10.5458/jag.57.145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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22
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23
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Improvement of alkaliphily of Bacillus alkaline xylanase by introducing amino acid substitutions both on catalytic cleft and protein surface. Biosci Biotechnol Biochem 2009; 73:965-7. [PMID: 19352020 DOI: 10.1271/bbb.80869] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Xylanase J (XynJ) from alkaliphilic Bacillus sp. 41M-1 is an alkaline xylanase. The crystal structure has been solved with XynJ. Improvement of the alkaliphily of XynJ was attempted by amino acid substitutions. Reinforcing the characteristic salt bridge in the catalytic cleft and introducing excess Arg residues on the protein surface shifted the optimum pH of the wild-type enzyme from 8.5 to 9.5.
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24
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Redecke L, Brehm MA, Bredehorst R. Cloning and characterization of dihydrofolate reductase from a facultative alkaliphilic and halotolerant bacillus strain. Extremophiles 2006; 11:75-83. [PMID: 17021659 DOI: 10.1007/s00792-006-0013-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Accepted: 06/30/2006] [Indexed: 10/24/2022]
Abstract
Elucidation of the molecular basis of the stability of enzymes from extremophilic organisms is of fundamental importance for various industrial applications. Due to the wealth of structural data from various species, dihydrofolate reductase (DHFR, EC 1.5.1.3) provides an excellent model for systematic investigations. In this report, DHFR from alkaliphilic Bacillus halodurans C-125 was cloned and expressed in E. coli. Functional analyses revealed that BhDHFR exhibits the most alkali-stable phenotype of DHFRs characterized so far. Optimal enzyme activity was observed in a slightly basic pH region ranging from 7.25 to 8.75. Alkali-stability is associated with a remarkable resistance to elevated temperatures (half-life of 60 min at 52.5 degrees C) and to high concentrations of urea (up to 3 M). Although the secondary structure shows distinct similarities to those of mesophilic DHFR molecules, BhDHFR exhibits molecular features contributing to its alkaliphilic properties. Interestingly, the unique phenotype is diminished by C-terminal addition of a His-tag sequence. Therefore, His-tag-derivatized BhDHFR offers the opportunity to obtain deeper insights into the specific mechanisms of alkaliphilic adaption by comparison of the three dimensional structure of both BhDHFR molecules.
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Affiliation(s)
- Lars Redecke
- Institute of Biochemistry and Food Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.
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25
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Kozak M. Synchrotron radiation small angle scattering studies of thermal stability of xylanase XYNII fromTrichoderma longibrachiatum. Biopolymers 2006; 83:668-74. [PMID: 16983650 DOI: 10.1002/bip.20605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Xylanase XYNII from Trichoderma longibrachiatum is a small protein of the molecular weight 21 kDa, belonging to the family 11 of glycosyl hydrolases, which catalyses hydrolysis of xylan. This article reports thermal stability study of xylanase XYN II conformation in the temperature range 15-65 degrees C by the small angle synchrotron radiation scattering. The study has been performed at different pH conditions: at pH 4.0 (below the physiological optimum of the enzyme activity) at pH 5.8 close to the optimum for enzymatic activity and at pH 8.0. The radius of gyration and the pair distance distribution function p(r) have been analyzed to characterize the changes of the enzyme conformation on heating. In the environment of the pH close to that of the optimum for the enzymatic activity, xylanase shows the greatest thermal stability and undergoes denaturation only above 55 degrees C. In the acidic and basic environments, the enzyme stability is much lower and denaturation begins at 45 degrees C. On the basis of the SAXS data, the shape of the xylanase molecule in solution in different temperatures has been reconstructed using ab initio method and program DAMMIN. The shape of the xylanase molecule at room temperature is similar to the right hand, which is typically observed for xylanase crystal structure. In higher temperatures (close to the enzyme activity optimum), the conformation of the right hand is loosened and half opened.
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Affiliation(s)
- Maciej Kozak
- Department of Macromolecular Physics, A. Mickiewicz University, Poznań, Poland.
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