Human dnase i hyperactive variants

Abstract

The present invention relates to amino acid sequence variants of human DNase I that have increased DNA-hydrolytic activity. The invention provides nucleic acid sequences encoding such hyperactive variants, thereby enabling the production of these variants in quantities sufficient for clinical use. The invention also relates to pharmaceutical compositions and therapeutic uses of hyperactive variants of human DNase I.

1 . A human DNase I hyperactive variant. 
     
     
         2 . A variant of  claim 1  that has DNA-hydrolytic activity that is at least 50% greater than that of native human DNase I as determined in a linear DNA digestion assay. 
     
     
         3 . A variant of  claim 1  that has DNA-hydrolytic activity that is at least 2-fold greater than that of native human DNase I as determined in a linear DNA digestion assay. 
     
     
         4 . A variant of  claim 1  comprising an amino acid sequence having at least 90% identity with the amino acid sequence of native human DNase I shown in  FIG. 1 . 
     
     
         5 . A variant of  claim 1  comprising an amino acid sequence having at least 95% identity with the amino acid sequence of native human DNase I shown in  FIG. 1 . 
     
     
         6 . A human DNase I hyperactive variant having an amino acid sequence that differs from the amino acid sequence shown in  FIG. 1  by the substitution of one amino acid for another at two or more positions within the  FIG. 1  sequence. 
     
     
         7 . A variant of  claim 6  wherein at least one of the amino acid substitutions is made at one of the following positions within the  FIG. 1  sequence: Gln9, Glu13, Thr14, His44, Asn74, Ser75, and Thr205. 
     
     
         8 . An isolated nucleic acid encoding a human DNase I hyperactive variant. 
     
     
         9 . The nucleic acid of  claim 8  comprising a nucleotide sequence that encodes an amino acid sequence having at least 90% identity with the amino acid sequence of native human DNase shown in  FIG. 1 . 
     
     
         10 . The nucleic acid of  claim 8  comprising a nucleotide sequence that encodes an amino acid sequence having at least 95% identity with the amino acid sequence of native human DNase shown in  FIG. 1 . 
     
     
         11 . The nucleic acid of  claim 8  comprising a nucleotide sequence that encodes an amino acid sequence that differs from the amino acid sequence shown in  FIG. 1  by the substitution of one amino acid for another at only a single position within the  FIG. 1  sequence. 
     
     
         12 . The nucleic acid of  claim 8  comprising a nucleotide sequence that encodes an amino acid sequence that differs from the amino acid sequence shown in  FIG. 1  by the substitution of one amino acid for another at two or more positions within the  FIG. 1  sequence.