ENZYMATIC CLEAVAGE AND REPAIR OF TRANSFORMING DNA

Abstract

Single-strand nicks caused by DNase I are capable of inactivating B. subtilis transforming DNA. Under suitable conditions, the polynucleotide joining enzyme from E. coli and a similar DPN-requiring activity from B. subtilis can completely repair this damage, restore biological activity, and increase the single-strand molecular weight. The rates of inactivation of a single genetic marker and of a four-marker linkage group suggest that a single-strand nick is inactivating even when far from the site of genetic damage.