L-lysine high-yield strain and its construction method and application
A construction method, lysine technology, applied in the field of L-lysine high-yield strains, can solve the problems of unknowable influence of strains, huge difficulty, and difficulty in small increase
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Embodiment 1
[0098] Example 1. Attenuation and inactivation of the hisB gene in Escherichia coli BW25113
[0099] Escherichia coli genome rapid manipulation technology using CRISPR / Cas9 【Zhao, D., et al. (2017). Science Rep 7(1):16624.], using the primers HisB-F and HisB-Ra in Table 1, adding the N20PAM fragment to the chloramphenicol resistance gene [Zhao, D., et al. (2017). Sci Rep 7(1):16624.] was used as a template and amplified by PCR to obtain the recombinant fragment hisBgtg for replacing the start codon atg of the hisB gene (SEQ ID NO: 1) of BW25113 with gtg. The plasmid pCAGO [Zhao, D., et al. (2017). Sci Rep 7(1):16624.] Transformed into BW25113 to obtain strain BW25113 (pCAGO). Prepare BW25113 (pCAGO) competent cells for electrotransformation. The medium used for the preparation of competent cells is: 10g / L peptone, 10g / L sodium chloride, 5g / L yeast powder, 10g / L glucose, and the final concentration is 0.1 mM IPTG. Transform the above-mentioned recombinant fragment hi...
Embodiment 2
[0103] Example 2. Attenuation and inactivation of the hisD gene in E. coli
[0104] Using the CRISPR / Cas9-based Escherichia coli genome rapid manipulation technology mentioned in Example 1, the hisD gene (SEQ ID NO:2) start codon of Escherichia coli BW25113 was replaced from atg to gtg, and the primers used were listed in Table 2 In HisD-F and HisD-Ra, the constructed strain was named BW25113-hisDgtg; in addition, using HisD-F and HisD-Rn in Table 2, using the same genome rapid operation technology, the hisD gene (SEQ ID NO :2) to edit the 8th to 14th bases, the 7th to 9th bases of the hisD gene after editing are TAA, forming a stop codon, so that the hisD gene cannot be expressed normally, thereby causing the inactivation of hisD, and the obtained The strain was named BW25113ΔhisD.
[0105] Table 2. Primers for constructing the recombinant fragments used for the weakened expression and inactivation of the hisD gene in Escherichia coli
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Embodiment 3
[0108] Example 3. Corynebacterium glutamicum B253 (GeneBank accession number CP010451) and 13032 (lysC T311I Knockout of hisB, hisN, hisD genes in )
[0109] First, using the method reported in the literature, the threonine codon at position 311 of the aspartokinase (lysC) gene of Corynebacterium glutamicum 13032 was replaced with an isoleucine codon by two-step recombination [ Ohnishi, J., et al. (2002). Appl Microbiol Biotechnol 58 (2): 217-223], obtained the strain 13032 (lysC T311I ).
[0110] Using CRISPR / Cas9 and activation-induced cytidine deaminase (AID) reported in the literature [Wang, Y., et al. (2018). Metab Eng47:200-210.], for B253 and 13032 (lysC T311I ) hisB, hisN, hisD genes were inactivated respectively.
[0111] The hisB gene (SEQ ID NO: 3) and 13032 (lysC) in B253 were synthesized in Table 3 respectively T311I ) in the hisB gene (SEQ ID NO:6) the 238th base C is mutated to T primers hisBF and hisBR, which are used to convert the hisN gene in B253 (SEQ...
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