NOVEL RECOMBINANT PLASMID PBSFOLEK1

摘要

PURPOSE:To provide a recombinant plasmid containing integrated gene of dihydrofolic acid reductase (DHFR)-leucine encephaline fused protein, stably replicable in E.coli and capable of imparting said host with trimethoprim resistance and ampicillin resistance. CONSTITUTION:Plasmid pBSDHFR1 is cut with restriction enzymes EcoRI and PstI and separated by 1% agarose gel electrophoresis to obtain a small fragment DNA. Separately, plasmid pBR322 is cut with restriction enzyme BamHI and Pst and separated by 1% agarose gel electrophoresis to obtain a large fragment DNA. The DNA of formula I and formula II are synthesized, the 5'-terminal is converted to phosphoric acid group and the product is annealed to obtain a DNA coding leucine encephaline. The above 3 kinds of DNA molecules are linked together, introduced into E.coli C600 strain and cultured. The objective recombinant DNA containing the sequence of formula III coding a DHFR-leucine encephaline fused protein can be separated from the obtained colony.