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A kind of glucose isomerase mutant and its application

A technology for glucose isomerase and mutants, which is applied in the field of glucose isomerase mutants, can solve the problem that the thermostability of high-temperature-resistant enzymes does not reach industrialized production and the like, and achieves the effect of excellent reusability.

Active Publication Date: 2020-08-21
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] At present, there have been some reports of heat-resistant GI, such as Thermotoga maritima and Thermusthermophiles, etc., and their optimum temperatures reach 105°C and 95°C, respectively. However, these enzymes have not been made into enzyme preparations and put on the market. The thermal stability of high-temperature enzymes at high temperatures does not meet the requirements of industrial production

Method used

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  • A kind of glucose isomerase mutant and its application
  • A kind of glucose isomerase mutant and its application
  • A kind of glucose isomerase mutant and its application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1: Construction and screening of ToGI single point mutants

[0029] 1. Mutant construction

[0030] According to the parental sequence of ToGI (the amino acid sequence is shown in SEQ ID NO.1, and the nucleotide sequence is shown in SEQ ID NO.2), the mutation primers for site-directed mutation were designed, and the recombinant vector pET28b / ToGI was used as a template by using rapid PCR technology. To introduce a single mutation at position 216, the primers are:

[0031] Forward primer GAACCCA NNN TTCGCTCACG (the underline is the mutated base)

[0032] reverse primer GAGCGAA NNN TGGGTTCAGAC (underline is the mutant base)

[0033] PCR reaction system: 2×Phanta Max Buffer (containing Mg 2+ ) 25μL, dNTPs 10mM, forward primer 2μL, reverse primer 2μL, template DNA 1μL, Phanta Max Super-Fidelity DNA Polymerase 50U, add ddH 2 0 to 50 μL.

[0034] The PCR amplification conditions were 95°C for 3min; (95°C for 15s, 50°C for 15s, 57°C for 6.5min) for 30 cycles; 72...

Embodiment 2

[0045] Example 2: Construction and screening of two-site mutants of glucose isomerase

[0046] According to the sequence of the single mutant ToGI-I constructed in Example 1, the mutation primers for site-directed mutation were designed, and using the rapid PCR technology, the recombinant vector pET28b / ToGI-I was used as a template to introduce a single mutation at position 228. The primers were:

[0047] Forward primer GAACTTC NNN CACGCTGTTG (the underline is the mutated base)

[0048] reverse primer CAGCGTG NNN GAAGTTCAGAC (the underline is the mutant base)

[0049] PCR reaction system: 2×Phanta Max Buffer (containing Mg 2+ ) 25μL, dNTPs 10mM, forward primer 2μL, reverse primer 2μL, template DNA 1μL, Phanta Max Super-Fidelity DNA Polymerase 50U, add ddH 2 0 to 50 μL.

[0050] The PCR amplification conditions were 95°C for 3min; (95°C for 15s, 50°C for 15s, 57°C for 6.5min) for 30 cycles; 72°C for 5min.

[0051] The PCR product was transformed into E.coliBL21 (DE3) co...

Embodiment 3

[0057] Example 3: Construction and screening of three-site mutants of glucose isomerase

[0058] Design mutation primers for site-directed mutation according to the mutant ToGI-II sequence constructed in Example 2, and use the rapid PCR technology to use the recombinant vector pET28b / ToGI-II as a template to introduce a single mutation at position 345. The primers are:

[0059] Forward primer GCTGGGT NNN TACTCTCGTG (the underline is the mutated base)

[0060] reverse primer GAGAGTA NNN ACCCAGCAGAC (the underline is the mutated base)

[0061] PCR reaction system: 2×Phanta Max Buffer (containing Mg 2+ ) 25μL, dNTPs 10mM, forward primer 2μL, reverse primer 2μL, template DNA 1μL, Phanta Max Super-Fidelity DNA Polymerase 50U, add ddH 2 0 to 50 μL.

[0062] The PCR amplification conditions were 95°C for 3min; (95°C for 15s, 50°C for 15s, 60°C for 6.5min) 30 cycles; 72°C for 5min.

[0063] The PCR product was transformed into E.coliBL21 (DE3) competent cells, and a single clo...

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Abstract

The invention discloses a glucose isomerase mutant and the application thereof in catalyzing D-glucose isomerization to prepare D-fructose. The glucose isomerase mutant is characterized in that the gene sequence of Thermus oshimai GI (ToGI) is treated as a template; after the template is subjected to three-bit site-specific mutagenesis, the plasmid pET-28b or a vector capable of expressing the enzyme is treated as an expression vector of the ToGI mutant, and Escherichia coli BL21 (DE3) or a strain capable of expressing the enzyme is treated as an expression host, and on the basis, the efficient expression of high-conversion-efficiency glucose isomerase gene is realized; the enzyme activity is 8.45U / mg. The ToGI mutant is outstanding in heat stability and remains the enzyme activity after being maintained in temperature of 100 DEG C for 7d. With the adoption of the immobilization technology, the conversion rate of 15 batches of D-fructose produced by continuously catalyzing 400g / L D-glucose through the catalyst under the temperature of 100 DEG C is beyond 60%.

Description

[0001] (1) Technical field [0002] The present invention relates to a glucose isomerase mutant, in particular to a method for obtaining a glucose isomerase mutant with super high temperature thermal stability by using gene mutation technology, and the immobilized glucose isomerase mutant is Application of continuous isomerization of glucose at high temperature to produce ultra-high fructose syrup with high D-fructose concentration. [0003] (2) Background technology [0004] Glucose isomerase (GI for short, EC 5.3.1.5) is mainly used to catalyze the isomerization of D-glucose to generate D-fructose in vitro, and is the key enzyme for the industrial production of high fructose syrup by biotransformation. According to the primary structure of GI, it can be divided into two classes, namely class I and class II enzymes. Compared with class I GI, the N-terminal of the peptide chain of class II GI contains 40-50 extra amino acid residues (Deng H. et al., Bioprocess and Biosystems E...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C12N9/92C12N11/08C12P19/02C12P19/24
CPCC12N9/92C12N11/08C12P19/02C12P19/24C12Y503/01005
Inventor 金利群贾东旭郑裕国柳志强王腾刘子健王远山
Owner ZHEJIANG UNIV OF TECH