Lactobacillus n-deoxyribosyl transferases, corresponding nucleotide sequences and their uses

Abstract

The invention concerns novel polypeptides and their fragments, isolated from Lactobacillus , having at least a N-deoxyribosyl transferase activity, the polynucleotides encoding said polypeptides, cloning and/or expression vectors including said polynucleotides, cells transformed by said vectors and specific antibodies directed against said polypeptides. The invention also concerns a method for enzymatic synthesis of deoxyribonucleosides.

1 . An isolated polypeptide comprising an amino acid sequence at least 90% identical to SEQ ID NO. 4, wherein said isolated polypeptide has the N-deoxyribosyltransferase activity of the amino-acid consisting of SEQ ID NO. 4. 
     
     
         2 . An isolated polypeptide comprising an amino acid sequence at least 90% identical to SEQ ID NO. 4, wherein said isolated polypeptide displays a deoxyribosyltransferase activity able to catalyse the exchange reaction dR−G+A<->dR−A+G. 
     
     
         3 . An isolated polypeptide comprising an amino acid sequence at least 90% identical to SEQ ID NO. 4, wherein said isolated polypeptide fulfils the guanine requirement of the  E. coli  PAK6 strain auxotrophic for guanine when said polypeptide is expressed in said strain. 
     
     
         4 . The isolated polypeptide according to  claim 1 , wherein said isolated polypeptide comprises an amino acid sequence at least 95% identical to SEQ ID NO.  4 . 
     
     
         5 . An isolated polypeptide comprising the amino acid sequence SEQ ID NO.  4 . 
     
     
         6 . An isolated polypeptide consisting of the amino-acid sequence SEQ ID NO.  4 . 
     
     
         7 . An isolated polypeptide consisting of a biologically active fragment of the amino-acid sequence SEQ ID NO. 4, wherein said isolated polypeptide has the N deoxyribosyltransferase activity of the amino-acid consisting of SEQ ID NO. 4. 
     
     
         8 . An isolated polypeptide consisting of a biologically active fragment of the amino-acid sequence SEQ ID NO. 4, wherein said isolated polypeptide displays a deoxyribosyltransferase activity able to catalyse the exchange reaction dR-G+A<->dR-A+G. 
     
     
         9 . An isolated polypeptide consisting of a biologically active fragment of the amino-acid sequence SEQ ID NO. 4, wherein said isolated polypeptide fulfils the guanine requirement of the  E. coli  PAK6 strain auxotrophic for guanine when said polypeptide is expressed in said strain. 
     
     
         10 . A recombinant N-deoxyribosyltransferase obtained by the expression of a polynucleotide sequence that encodes a polypeptide at least 90% identical to SEQ ID NO. 4 in an appropriate host cell. 
     
     
         11 . A recombinant N-deoxyribosyltransferase obtained by the expression of a polynucleotide sequence that encodes a polypeptide at least 95% identical to SEQ ID NO. 4 in an appropriate host cell. 
     
     
         12 . A recombinant N-deoxyribosyltransferase obtained by the expression of pLH4 vector comprising a polynucleotide encoding the polypeptide of SEQ ID NO. 4 in an appropriate host cell. 
     
     
         13 . The isolated polypeptide according to  claim 2 , wherein said isolated polypeptide comprises an amino acid sequence at least 95% identical to SEQ ID NO.  4 . 
     
     
         14 . The isolated polypeptide according to  claim 3 , wherein said isolated polypeptide comprises an amino acid sequence at least 95% identical to SEQ ID NO.  4 .