Co-expression of human cytochrome b5 increases expression of cytochrome P450 3A4 in Escherichia coli by stabilizing mRNA

CYP3A4 is the most abundant cytochrome P450 in the human liver. The expression level of CYP3A4 when coexpressed with cytochrome b5 (cyt b5) in Escherichia coli was 20–60% higher than that when it was expressed alone over an extended period (48–72 h). This time-dependent elevation in coexpression with cyt b5 was a result of an increase in CYP3A4 mRNA half-life; no significant change in CYP3A4 degradation was seen in the bacterial protease fraction. These results suggest that the higher CYP3A4 levels observed upon coexpression with cyt b5 primarily resulted from CYP3A4 mRNA stabilization by cyt b5.

► Coexpression of CYP3A4/hOR with cyt b5 in E. coli increased CYP3A4 expression level. ► High affinity was observed between CYP3A4, hOR, and cyt b5 in E. coli membranes. ► Level of CYP3A4 mRNA coexpressed with cyt b5 increased in a time-dependent manner. ► Coexpression of CYP3A4 with cyt b5 increased the half-life of CYP3A4 mRNA.