title: Reconstitution of colicin E2-induced deoxyribonucleic acid degradation in spheroplast preparations.
abstract: Spheroplasts are insensitive to colicin E(2) and do not show deoxyribonucleic acid (DNA) degradation even in the presence of massive amounts of E(2). However, when both endonuclease I and E(2) were present, spheroplast DNA was degraded by an endonucleolytic activity which gave rise primarily to double-strand DNA cleavages, producing fragments having an average molecular weight of 9 x 10(6). Pancreatic ribonuclease could substitute for colicin E(2) in the reconstitution system, but pancreatic deoxyribonuclease could not replace endonuclease I. However, colicin E(2) could not activate transfer ribonucleic acid-inhibited endonuclease I in an in vitro system where pancreatic ribonuclease caused full stimulation.
mesh_terms: D002499:Centrifugation, Density Gradient; D003087:Colicins / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D013104:Spheroplasts / Q000187:drug effects / Q000378:metabolism*
chemical_list: D003087:Colicins; D004269:DNA, Bacterial; D004720:Endonucleases