The object of the present invention relates to a Mini-III RNase having an amino acid sequence, which is implantable in the Mini-III RNase structure, forming an acceptor moiety and an α4 helix and α5b-α6 loop structure, respectively. Fragments comprising an α4 helix and an implantable α5b-α6 loop, where the structures forming the α4 helix and α5b-α6 loop are each a Mini-III RNase from Bacillus subtilis shown in SEQ ID NO: 1. Are structurally corresponding to the structures of the α4 helix and α5b-α6 loop formed by the amino acid sequence fragments at positions 46-52 and 85-98, respectively, where Mini-III RNase is To the ribonucleotide sequence of the substrate Shows sequence specificity in dsRNA cleavage that is dependent and independent of the appearance of secondary structure in the structure of the substrate, and independent of the presence of other accessory proteins, and Mini-III RNase is SEQ It is not a Mini-III protein from ID NO: 1 or from Bacillus subtilis with SEQ ID NO: 1 having the D94R mutation. The present invention also includes a method for obtaining a chimeric Mini-III RNase, a construct encoding Mini-III RNase, a cell having a gene encoding Mini-III RNase, the use of Mini-III RNase for dsRNA cleavage, It relates to a method of cleaving dsRNA that depends only on ribonucleotide sequences. [Selection figure] None
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