Western blot analysis of proteins derived from the cloned melR (A) and soxR (B) genes. (Left panels) Schematic drawings of variant melR and soxR genes encoding N-terminally His6-tagged proteins. The elevated arrow denotes the start and direction of transcription. The hatched and open rectangles represent the coding regions for 6 × His and MelR or SoxR, respectively. The figures are not drawn to scale. The black bars represent the DIG-labeled DNA probes used for Northern analysis. (Right panels) The results of Western blot analysis of N-terminally His6-tagged proteins. TA331 (ssrA−), W3110 (ssrA+), and TA371 (ssrADD), harboring pMelR or pSoxR, were grown to OD600 = 0.7. The synthesis of His6-tagged proteins was induced for 20 min by adding 0.1 mM IPTG. Total extracts were prepared and lysates equivalent to 0.1 OD600 unit were subjected to Western blot analysis using anti-His-tag antibody. Asterisks indicate the positions of the full-length His6-MelR (36.9 kD) or His6-SoxR (18.6 kD). Size standards are on the right.
