Involvement of NAD in induced synthesis of colicin E1

Escherichia coli K-12 nadC13 (ColE1) was starved for nicotinic acid and cellular NAD levels decreased to less than 10% of the normal. Under these conditions, induction of colicin E1 synthesis decreased to about 1% of the normal value, while 30% of the total protein synthesis remained intact. Addition of nicotinic acid reversed both the ability of the colicin induction and cellular NAD level. Induced replication of colicin E1 DNA was greatly reduced in the NAD-deprived cells.