The present invention relates to a customized synthesized sRNA for reducing
gene expression in a prokaryotic
cell having a new structure, to a method for preparing the synthesized sRNA and to a use of the synthesized sRNA. More particularly, the present invention relates to a synthesized sRNA which contains an Hfg
binding site derived from any one sRNA of MicC, SgrS and MicF, and a zone for forming complementary binding with
target gene mRNA. The present invention also relates to a method for preparing the synthesized sRNA and to a use of the synthesized sRNA.; The synthesized sRNA according to the present invention has the advantages of regulating the degree of inhibition by regulating the
binding force to mRNA of the
target gene, and can be effectively produced without deleting an existing
gene through synthesized sRNA for regulating
gene expression and may reduce an expression of the
target gene, thus enabling the synthesized sRNA of the present invention to be valuably used in the production of recombinant microorganisms. The synthesized sRNA of the present invention may be quickly applied to various strains, and therefore, is very suitable for measuring the metabolizability of each strain and selecting an optimum strain.; In addition, recombinant microorganisms for producing
tyrosine or
cadaverine at a high efficiency according to the present invention, obtained by regulating metabolic flux of microorganisms by means of synthesized sRNA can be valuably used as microorganisms for drugs and industrial solvents. That is, selecting an expression inhibitory target gene for high efficiency production of metabolites can be easily performed using the sRNA of the present invention. Thus, the sRNA of the present invention can be used in producing recombinant strains for the efficient production of various metabolites and in establishing methods for producing efficient production, and thus is very useful.