[Expression of plasmid R6K in a cell-free coupled transcription-translation system]

The modified method for obtaining E. coli extract S 30 for the coupled transcription--translation system is described. The extract treated with immobilized DNAase and micrococcal nuclease had the minimal endogenous protein synthesis and high activity in respect to exogenous DNA matrices. The synthesis of 9-12 proteins with molecular weights ranging from 14,000 to 178,000 daltons was shown to occur in this system in the presence of the DNA of R6K plasmid. The use of the modification of Novick's method allowed to identify active beta-lactamase coded by the amp-gene of R6K plasmid.