Fig. 9: Mutagenesis and evolution of LysE exporter for higher L-Arg tolerance. | Nature Communications

Fig. 9: Mutagenesis and evolution of LysE exporter for higher L-Arg tolerance.

From: An orthogonal transcription mutation system generating all transition mutations for accelerated protein evolution in vivo

Fig. 9

a Scheme of the evolution and selection procedure for LysE exporter. lysE gene is controlled by the constitutive Pporin42 promoter, with MmP1 promoter at both ends. Arg represents L-arginine. b Growth curve analysis of the LysE 6 M mutant and wild-type LysE in 5 g/L L-Arg 50MM medium. c Shake flask results of the LysE 6 M mutant and wild-type LysE in 5 g/L L-Arg 50MM medium. d Structure analysis of LysE, highlighting mutations in magenta. e, f Three-dimensional interaction of the LysE 6 M mutant and wild-type LysE with L-Arg. The green dotted lines represent hydrogen bonds. g, h Two-dimensional interaction of the LysE 6 M mutant and wild-type LysE with L-Arg. The green dotted lines represent hydrogen bonds. i The RMSF results of the LysE 6 M mutant and wild-type LysE with L-Arg.The loop region and the two helical regions are highlighted by blue and green boxes, respectively. j The RMSD results of the LysE 6 M mutant and wild-type LysE with L-Arg. Data are presented as mean values and standard errors (error bars). n = 3, which represents three independent replicates of the experiment. Statistical analyses were performed using two-tailed Student’s t-tests. A p-value < 0.05 was considered significant. Source data are provided as a Source Data file.

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