Abstract
The physiological functions of the Escherichia coli fumarases A, B, and C (FUMA, B and C) were investigated using strains containing multicopy plasmids expressing each of the fum genes, and with single-copy fum-lacZ fusions. The results showed that FUMA is the critic acid cycle enzyme because it was strongly expressed under aerobic conditions but repressed by glucose and anaerobiosis. FUMB and FUMC were less susceptible to repression by glucose and anaerobiosis, and FUMB was identified as an anaerobic enzyme because its anaerobic expression was controlled by the anaerobic transcriptional activator, FNR. The expression of an aspA-lacZ fusion was also shown to be fnr-dependent.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
