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.

What is claimed is:  
     
         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 only a single position within the FIG. 1 sequence.  
     
     
         7 . A variant of  claim 6  wherein the amino acid substitution is at one of the following positions within the FIG. 1 sequence: Gln9, Glu13, Thr14, His44, Asn74, Ser75, and Thr205.  
     
     
         8 . 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.  
     
     
         9 . A variant of  claim 8  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, Ser7S, and Thr205.  
     
     
         10 . An isolated nucleic acid encoding a human DNase I hyperactive variant.  
     
     
         11 . The nucleic acid of  claim 10  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.  
     
     
         12 . The nucleic acid of  claim 10  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.  
     
     
         13 . The nucleic acid of  claim 10  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.  
     
     
         14 . The nucleic acid of  claim 10  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.  
     
     
         15 . A method for the treatment of a patient having a pulmonary disease or disorder comprising administering to the patient a therapeutically effective amount of a human DNase I hyperactive variant.  
     
     
         16 . The method of claim is wherein the disease or disorder is cystic fibrosis.  
     
     
         17 . A method for the treatment of a patient having systemic lupus erythematosus comprising administering to the patient a therapeutically effective amount of a human DNase I hyperactive variant.  
     
     
         18 . A pharmaceutical composition comprising a human DNase I hyperactive variant and optionally a pharmaceutically acceptable excipient.  
     
     
         19 . The composition of  claim 18  wherein the composition is in liquid form.  
     
     
         20 . The composition of  claim 18  wherein the composition is in powder form.