Lactobacillus beta-glucuronidase and DNA encoding the same

Abstract

The present invention provides isolated β-Glucuronidase (GUS) having activity at acidic pH and nucleic acids encoding the same. The nucleic acids may be isolated from any suitable species, and in a preferable embodiment are isolated from Lactobacillus gasseri.

That which is claimed is:  
     
         1 . An isolated nucleic acid encoding β-glucuronidase (GUS), said isolated nucleotide selected from the group consisting of: 
 (a) DNA having the nucleotide sequence given herein as SEQ ID NO:1;  
 (b) polynucleotides that hybridize to DNA of (a) above under stringent conditions represented by a wash stringency of 50% Formamide with 5× Denhardt's solution, 0.5% SDS and 1×SSPE at 42° C., and which encode a β-glucuronidase (GUS) protein; and  
 (c) polynucleotides that differ from the DNA of (a) or (b) above due to the degeneracy of the genetic code, and which encode the protein encoded by a DNA of (a) or (b) above.  
 
     
     
         2 . An isolated nucleic acid according to  claim 1  encoding a GUS protein having a peak activity at a pH of from 3 to 5.  
     
     
         3 . An isolated nucleic acid according to  claim 1  which encodes the protein having the amino acid sequence given herein as SEQ ID NO:2.  
     
     
         4 . A recombinant nucleic acid comprising a promoter operably linked to an isolated nucleic acid encoding a GUS according to  claim 1 .  
     
     
         5 . A vector comprising an isolated nucleic acid according to  claim 1 .  
     
     
         6 . A vector according to  claim 5 , wherein said vector is a plasmid.  
     
     
         7 . A vector according to  claim 5 , wherein said vector is an Agrobacterium vector.  
     
     
         8 . A host cell containing heterologous nucleic acid according to  claim 1  and expressing the encoded GUS protein.  
     
     
         9 . A host cell according to  claim 8 , wherein said host cell is a plant cell.  
     
     
         10 . A host cell according to  claim 8 , wherein said host cell is an animal cell.  
     
     
         11 . A host cell according to  claim 8 , wherein said host cell is a yeast cell.  
     
     
         12 . A host cell according to  claim 8 , wherein said host cell is a bacterial cell.  
     
     
         13 . A host cell according to  claim 8 , wherein said host cell is a lactic acid bacteria cell.  
     
     
         14 . A method of making a recombinant cell, comprising transforming a host cell with a vector according to  claim 7 .  
     
     
         15 . A method according to  claim 14 , further comprising the step of expressing the encoded GUS protein in said host cell.  
     
     
         16 . A method according to  claim 14 , further comprising the step of detecting said encoded GUS protein in said host cell.  
     
     
         17 . A method according to  claim 14 , further comprising the step of collecting said encoded GUS protein from said host cell.  
     
     
         18 . An isolated β-glucuronidase (GUS) protein encoded by a nucleic acid selected from the group consisting of: 
 (a) DNA having the nucleotide sequence given herein as SEQ ID NO:1;  
 (b) polynucleotides that hybridize to DNA of (a) above under stringent conditions represented by a wash stringency of 50% Formamide with 5× Denhardt's solution, 0.5% SDS and 1×SSPE at 42° C., and which encode a β-glucuronidase (GUS) protein; and  
 (c) polynucleotides that differ from the DNA of (a) or (b) above due to the degeneracy of the genetic code, and which encode the protein encoded by a DNA of (a) or (b) above.  
 
     
     
         19 . An isolated GUS protein according to  claim 18  having the amino acid sequence given herein as SEQ ID NO: 2.  
     
     
         20 . An antibody that specifically binds to an isolated GUS protein according to  claim 18.