Fig. 3

Effect of site-directed mutations in the active site of CvPHBH on 4-amino-3-hydroxybenzoic acid (4,3-AHBA) productivity of Corynebacterium glutamicum. A Three-dimensional structural model of CvPHBH. The brown stick represents the selected residues in the active site. The green stick represents 4-aminobenzoic acid (4-ABA). The sky-blue stick represents FAD. The dotted line represents hydrogen bonds. The molecular structure model was visualized using the PyMOL Molecular Graphics System (Version 2.0, Schrödinger, LLC, New York, NY, USA). B The results of HPLC analysis of the culture supernatants of C. glutamicum strains expressing site-directed mutants of CvPHBH. White and gray colored bars indicate the concentration of 4-ABA and 4,3-AHBA, respectively. Data are represented as mean ± standard deviation of biological replicates (n = 6). Yellow circles indicate the mean percentage of 4,3-AHBA. The horizontal axis indicates the strains of interest expressing CvPHBH mutants. WT: wild type