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A method for reducing the inhibitory effect of cyclodextrin on pullulanase

A pullulanase, inhibitory technology, applied in the fields of genetic engineering, enzyme engineering or food science, can solve problems such as unproposed solutions

Active Publication Date: 2019-11-22
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Relevant studies at home and abroad only focus on the interaction between cyclodextrin and pullulanase, and no specific and effective solutions have been proposed

Method used

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  • A method for reducing the inhibitory effect of cyclodextrin on pullulanase
  • A method for reducing the inhibitory effect of cyclodextrin on pullulanase
  • A method for reducing the inhibitory effect of cyclodextrin on pullulanase

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Embodiment 1

[0030] A method for rationally mutating key amino acids of pullulanase, said method comprising the steps of:

[0031] (1) Using the pullulanase (PDB: 2E8Z) from Bacillus subtilis str.168, which has a known crystal structure of the interaction between cyclodextrin and pullulanase, as a template, its NCBI The accession number is AF008220.1, and the pullulanase gene sequence AmyX was synthesized by chemical total synthesis. The plasmid used to construct the expression vector in E. coli is pET20b(+) with T7 promoter.

[0032] (2) The pET20b(+) plasmid and the plasmid containing the AmyX gene were double-digested with NcoI and BamI respectively, and the digested products were recovered by tapping and then ligated with T4 ligase, and the ligated products were transformed into E.coli DH5α competent cells, Cultivate at 37°C for 8-12 hours, pick the transformant and shake it in liquid LB medium containing 100 μg / mL ampicillin, extract the plasmid, and verify it by enzyme digestion to ...

Embodiment 2

[0055] A method for rationally mutating key amino acids of pullulanase, said method comprising the steps of:

[0056] (1) Using the pullulanase (PDB: 2E8Z) from Bacillus subtilis str.168, which has a known crystal structure of the interaction between cyclodextrin and pullulanase, as a template, its NCBI The accession number is AF008220.1, and the pullulanase gene sequence AmyX was synthesized by chemical total synthesis. The plasmid used to construct the expression vector in E. coli is pET20b(+) with T7 promoter.

[0057] (2) The pET20b(+) plasmid and the plasmid containing the AmyX gene were double-digested with NcoI and BamI respectively, and the digested products were recovered by tapping the rubber, and then ligated with T4 ligase, and the ligated products were transformed into E.coli DH5α competent cells , cultured at 37°C for 8-12 hours, picked the transformant and cultured it in liquid LB medium containing 100 μg / mL ampicillin with shaking, extracted the plasmid, and v...

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Abstract

The invention discloses a method for reducing the inhibitory effect of cyclodextrin on pullulanase. In the method, a mutant of pullulanase is prepared by rationally mutating key amino acids in the interaction between pullulanase and cyclodextrin , to reduce the inhibitory effect of cyclodextrin on pullulanase, thereby increasing the hydrolysis activity of pullulanase. Based on the analysis of the crystal structures of enzymes and inhibitors and the sequence comparison of enzymes from different sources, the present invention finds out the site where pullulanase interacts with cyclodextrin, and uses site-directed mutation to obtain pullulan with reduced sensitivity to cyclodextrin. Lanzyme mutants, thereby improving the utilization rate of starch raw materials and the yield of cyclodextrin.

Description

technical field [0001] The invention relates to the fields of genetic engineering, enzyme engineering or food science and technology, in particular to a method for transforming pullulanase by genetic engineering site-directed mutation, thereby reducing the inhibitory effect of cyclodextrin on pullulanase. Background technique [0002] Pullulanase (Pullulanase, EC 3.2.1.41) specifically hydrolyzes α-1,6 glycosidic bonds in pullulan, soluble starch, amylopectin and corresponding oligosaccharides to generate short linear dextrins. The compound use with other amylases can greatly improve the utilization rate of starch raw materials, so it is widely used in the starch industry. [0003] In the starch sugar industry, pullulanase has the function of hydrolyzing α-1,6 glycosidic bonds, so it has broad application prospects. It can be used to prepare amylose, maltose, branched cyclodextrin, and compound with CGTase to produce cyclodextrin Refined. In the production process of cyclo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C12N9/44C12N15/10
CPCC12N9/2457C12Y302/01041C12N15/70C12N15/75C12N9/2402
Inventor 金征宇柏玉香李晓晓纪杭燕田耀旗焦爱权周星王金鹏赵建伟谢正军徐学明
Owner JIANGNAN UNIV