Fig. 2

Performance of the CRISPRi system targeting aconitate biosynthesis-related enzymes in glucose pathways. a Structural diagram and gRNA sequence of the CRISPRi system. b The effect of CRISPRi system targeting icdA expression on isocitrate dehydrogenase (IDH) activity in E. coli. Relative expression of icdA gene in E. coli strain harboring CRISPRi system (Top). IDH activity in recombinant E. coli (Bottom). c Effect of CRISPRi system targeting pykA/F on pyruvate kinase (PK) activity in E. coli. Relative expression levels of pykA and pykF genes in E. coli strains (Top). PK activity in recombinant E. coli (Bottom). d Effect of CRISPRi system targeting both icdA and pykF genes on IDH and PK activities in E. coli. Relative expression levels of icdA and pykF in E. coli strains harboring CRISPRi system (Top). Activities of IDH and PK in recombinant E. coli (Bottom). IDH: isocitrate dehydrogenase (EC 1.1.1.42, encoded by icdA gene); PK: pyruvate kinase (EC 2.7.1.40, encoded by pykA and pykF). WT: wild-type E. coli BL21(DE3) without CRISPRi system; control: recombinant E. coli with non-targeting CRISPRi system; icdA1, icdA2 and icdA3: recombinant E. coli harboring CRISPRi system targeting different regions of icdA gene; pykA1, pykA2 and pykA3: recombinant E. coli containing CRISPRi system targeting different regions of pykA gene; pykF1, pykF2 and pykF3: recombinant E. coli carrying the CRISPRi system targeting various regions of pykF gene. Mean ± S.E. (n = 3). *P < 0.05; **P < 0.01