Cloning and expression of escherichia coli K-12 $trpL({\Delta}att)\;trpE^{FBR}$ gene in klebsiella pneumoniae

Klebsiella pneumoniae에 있어서의 escherichia coli K-12 $trpL({\Delta}att)\;trpE^{FBR}$유전자의 클로닝 및 발현

A modified E. coli trp operon, $trpL({\Delta}att)\;trpE^{FBR}$, was conjugally transfered into Klebsiella pneumoniae $KC_{100}\;(Phe^-,\;Tyr^-,\;Trp^-,\;Rif^r,\;Kam^r)$ by in vivo cloning using the hybrid plasmid $R_{6}K::$ Mucts 61 with a transfer frequency of $5.2{\times}10^{-7}$. Two K. pneumoniae transconjugants, $KUA_{701}\;and\;KUA_{702}$, were isolated. The characters of attenuation control-free and resistance to feedback-inhibition which are characteristics of donor C. coli trp operon were normally expressed in the $KUA_{701}.\;However,\;KUA_{702}$ retained only the feedback-inhibition resistant character. $Trp^+$ phenotype and ampicillin resistant character were completely stable in the transconjugants, but streptomycin resistant character was lost in the transconjugants.