Additional file 1: Figure S1. 12% SDS-PAGE gel showing overexpression of TetR family protein. A) Expression in different expression strains. Lane1: marker, lane2: uninduced sample (BL21(DE3)), lane3: induced sample (BL21(DE3)), lane4: uninduced sample (Codon Plus), lane5: induced sample (Codon Plus), lane6: uninduced sample (BL21(DE3) pLysS), lane7: induced sample (BL21(DE3) pLysS). B) Expression of protein in BL21 DE3 pLysS at different time intervals. Lane1: marker, lane2: uninduced sample, lane3: 3 h induction sample (pellet), lane4: 3 h induction sample (supernatant), lane5: 5 h induction sample (pellet), lane6: 5 h induction sample (supernatant), lane7: 7 h induction sample (pellet), lane8: 7 h induction sample (supernatant), lane9: overnight induction sample (pellet), lane10: overnight induction sample (supernatant). Figure S2. Peptide fragments identified by MALDI and its similarity with the TetR family transcription regulator in Gordonia. Figure S3. Biodesulfurization activity in E. coli when TetR family protein is supplied in trans via plasmid demonstrated by Gibbs assay. Graph showing production of 2 HBP in cells containing pTB2 (dsz operon) and pTB2 + TetR induced with IPTG. The experiment was performed in triplicates. Figure S4. A 12% SDS-PAGE gel showing the expression of the TetR family protein when induced with different inducer concentrations. Lane1: marker, lane2: E. coli cells with uninduced TetR family protein, lane3-6: E. coli cells with induced TetR family protein (0.2 mM, 0.5 mM, 1 mM and 2 mM IPTG concentration).