Improving the catalytic activity of thermostable xylanase from Thermotoga maritima via mutagenesis of non-catalytic residues at glycone subsites

ABSTRACT Xylanase activity assays were used to screen a Streptomyces coelicolor genomic library in Escherichia coli, and a xylanase gene that is 99% identical to the xylanase B gene (xlnB) of S. lividans (GenBank accession no. M64552 ) was identified. The promoter region of this gene was identified by using a transcriptional fusion between the upstream region of the S. coelicolor xlnB gene and thexylE reporter gene. Transcription from the xlnBpromoter was found to be induced by xylan and repressed by glucose. A single apparent transcription start site was identified by both primer extension analysis and in vitro run off transcription assays. Analysis of deletions of the promoter identified a region required for glucose repression. By using the transcriptional and protein localization signals of the Streptomyces xlnB gene, an in-frame translational fusion between the end of the xlnB signal sequence and the ATG of the Thermotoga maritima xynA gene was constructed. The xynA gene encodes a thermostable xylanase that has been demonstrated to be useful in the bleaching of Kraft pulp. The xlnB-xynA gene fusion was expressed inStreptomyces, and the activity of the protein produced was thermostable and was localized to the supernatant fraction of harvested cells.

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Faculty Opinions recommendation of Effect of dimerization on the stability and catalytic activity of dihydrofolate reductase from the hyperthermophile Thermotoga maritima.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1160814.622227 ◽

2009 ◽

Author(s):

Vivian Cody

Keyword(s):

Catalytic Activity ◽

Dihydrofolate Reductase ◽

Thermotoga Maritima ◽

The Stability

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Effect of the thermostable xylanase B (XynB) from Thermotoga maritima on the quality of frozen partially baked bread

Journal of Cereal Science ◽

10.1016/j.jcs.2007.03.013 ◽

2008 ◽

Vol 47 (2) ◽

pp. 172-179 ◽

Cited By ~ 29

Author(s):

Zhengqiang Jiang ◽

Alain Le Bail ◽

Aimin Wu

Keyword(s):

Thermotoga Maritima ◽

Thermostable Xylanase

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Correlation of the conformational structure and catalytic activity of the highly thermostable xylanase of Thermomyces lanuginosus PC7S1T

Biocatalysis and Biotransformation ◽

10.1080/10242422.2021.1950696 ◽

2021 ◽

pp. 1-12

Author(s):

Carla Lieko Della Torre ◽

Rosemeire Aparecida Silva-Lucca ◽

Rodrigo da Silva Ferreira ◽

Luciana Andrade Luz ◽

Maria Luiza Vilela Oliva ◽

...

Keyword(s):

Catalytic Activity ◽

Thermomyces Lanuginosus ◽

Conformational Structure ◽

Thermostable Xylanase

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Impact of orientation of carbohydrate binding modules family 22 and 6 on the catalytic activity of Thermotoga maritima xylanase XynB

Enzyme and Microbial Technology ◽

10.1016/j.enzmictec.2017.07.004 ◽

2017 ◽

Vol 106 ◽

pp. 75-82 ◽

Cited By ~ 7

Author(s):

Razia Tajwar ◽

Saher Shahid ◽

Rehan Zafar ◽

Muhammad Waheed Akhtar

Keyword(s):

Catalytic Activity ◽

Thermotoga Maritima ◽

Carbohydrate Binding ◽

Carbohydrate Binding Modules

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Clone, Expression, and Purification of a Hyperthermophilic Endoglucanase Gene Cel12B from Thermotoga maritima

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.5528 ◽

2012 ◽

Vol 518-523 ◽

pp. 5528-5532

Author(s):

Hao Shi ◽

Xun Li ◽

Xiang Qian Li ◽

Fei Wang

Keyword(s):

Escherichia Coli ◽

Enzyme Activity ◽

Catalytic Activity ◽

Affinity Chromatography ◽

Thermotoga Maritima ◽

Molecular Engineering ◽

Expression And Purification ◽

Escherichia Coli Bl21 ◽

His Tag ◽

Constructed Plasmids

The thermostability and catalytic activity of endoglucanase from thermophilic Thermotoga maritima were improved by evolutionary molecular engineering. The cel12B gene from Thermotoga maritima was cloned and expressed, and the expressed Cel12B protein was purified by His-tag affinity chromatography. The constructed plasmids were screened on LB plate with ampicillin using Escherichia coli BL21 (DE3) as a host. The results showed that both the enzyme activity and yield of the Cell12B protein expressed in pET15b-cel12B were 2 times as that of the protein expressed in pET20b-cel12B.

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High resolution electron microscopy of lanthanum phosphate crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108519 ◽

1978 ◽

Vol 36 (1) ◽

pp. 274-275

Author(s):

J. C. Wheatley ◽

J. M. Cowley

Keyword(s):

Electron Microscopy ◽

Catalytic Activity ◽

High Resolution ◽

Petroleum Industry ◽

High Resolution Electron Microscopy ◽

Lanthanum Phosphate ◽

Good Catalyst ◽

Resolution Electron ◽

Good Catalytic Activity ◽

Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

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