title: Cell-free synthesis of proteins coding for mobilisation functions of ColE1 and transposition functions of Tn3.
abstract: A hybrid plasmid, pJC74, carrying the large (3.35 Md) EcoRI-PstI fragment of ColE1, the 1.3 and 1.8 Md PstI fragments of plasmid R1 drd19 (containing a part of Tn3 and known to specify transpostion functions), and a part of gamma bacteriophage DNA carrying the fused cohesive ends of gamma (cos) was constructed. Supercoiled DNA of pJC74 and a series of deletions (series pJC75) were used in a cell-free coupled transcription-translation system. Analysis of the proteins produced allowed the identification of a 28 to 30 kd protein and/or a 3 kd protein responsible for mobilisation of the plasmids in sex-factor-promoted conjugation. Furthermore, three protein bands of 12, 12.5 and 13 kd were correlated with the presence of a portion of the Tn3 transposon previously shown to code for transposition functions which can complement in trans. These latter and the 30 kd beta-lactamase were the only proteins identified as Tn3-specific by comparison of ColE1 with RSF2124.
mesh_terms: D002474:Cell-Free System; D003090:Coliphages / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D004274:DNA, Recombinant / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005796:Genes; D010957:Plasmids; D014176:Protein Biosynthesis; D011995:Recombination, Genetic; D014158:Transcription, Genetic
chemical_list: D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004279:DNA, Viral