Fig. 3

Construction of the whole-cell biocatalyst and improvement of its efficiency via screening CYP11B1 sources from the wild-type enzymes and N-terminal mutants. a The sketch of Adx _4–108 -CPY11B1-AdR co-expression plasmids (pETXST39–56) for steroids conversion. b The HPLC profile of strain EC02040107 (black) as well as the standard of 21-DF (blue) and 17-OHP (yellow). The signals of 21-DF, 17-OPH and the by-product were detected at 240 nm. c 21-DF transformation rates in shake flask fermentation. Strains EC02040101–08 carried wild-type CYP11B1s from diversity species, while strains EC02040110–17 harbored different CYP11B1s with mutated N-terminus. The mutagenesis, which were equal to the mutations reported in H. sapiens (Hs_G25R, Hs_G46R and Hs_L52M), were listed below their corresponding strain names. Symbol “-” was for unmutated residue, and symbol “/” suggested this mutation has existed in the associated enzymes. In the meanwhile, no 21-DF has been detected in the product of strain EC02040108, which was marked by blue star