Five hundredfold overproduction of DNA ligase after induction of a hybrid lambda lysogen constructed in vitro

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Science  08 Apr 1977:
Vol. 196, Issue 4286, pp. 188-189
DOI: 10.1126/science.322281


A lambda vector that contains the gene for Escherichia coli DNA ligase (lambdagt4-lop-11 lig+) has been modified to achieve overproduction of this enzyme. The third Eco RI site in the lambda chromosome has been altered by mutation, and the left-hand Eco RI fragment has been shortened. The new vector, lambdagt4-lop-11 lig+, forms a stable lysogen which, upon induction, produces a 100-fold increase in DNA ligase activity. Introduction of a phage mutation (S7) that prevents cell lysis results in an even greater increase (500-fold).