Abstract
Gene 56 of bacteriophage T4 was previously shown to control deoxycytidine triphosphatase (dCTPase), an enzyme known also to dephosphorylate dCDP, dUTP, and dUDP. Whether this control is direct or indirect was not clear. In the present study we examined the heat lability of the dCTPases produced by gene 56 amber mutants in four different amber-suppressor strains. Others have shown that tyrosine and glutamine are inserted at the amber codon by two of these suppressor strains; the other two insert serine. With one mutant, amE51×5, no difference in heat lability from the wild-type enzyme was observed in the enzymes produced by any of the four suppressor strains. With another mutant, amC153×1, a marked increase in heat lability was observed when the suppressor strains were those inserting tyrosine or serine, but not glutamine. These and other observations constitute strong evidence that gene 56 is a structural gene for the enzyme dCTPase.
Published Version
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