Fig. 3

A Vector diagram of pET-CmE1b2; B SDS-PAGE analysis of protein expression of E. coli BL21(DE3), BL21-pBAD-EgtD, BL21-pET-CmE1b2 (E1B2) and BL21-EgtD1b2 (E1B2D). (The supernatant (SP) and cell pellet (CP) of samples after the process of cell sonication and centrifuge; CmE1b, 59.5 kDa; CmEgt2, 53.8 kDa; EgtD, 36.4 kDa; putative proteins were pointed out by arrow); C The HPLC analysis (partly chromatogram of the retention time from 36.5 to 58.5 min, all the sample performed at the same condition and showed in same intensity) of in vivo reaction by supernatant from the fermented E. coli samples; D The putative ergothioneine synthesis pathway of BL21-EgtD1B2