Patent ID: 7892838

Claim:
A method for evolving a N-deoxyribosyltransferase (DTP) so as to modify its characteristics, the method comprising a) obtaining mutants X* from the sequence coding for the DTP by random mutagenesis; b) transforming E. coli cells comprising at least one genotype ΔpyrC, Δcod A, and Δcdd and which E. coli cells are deficient in the metabolic pathway leading to uracil and a phenotype [P-] with vectors comprising the mutated nucleic acids obtained in stage a) coding for the mutants X*, P-signifying that said E. coli cells are auxotrophic for the substance P, P being the product of the action of X on its natural substrate S; c) culturing said E. coli cells in a medium comprising a substrate S*, S* being an analogue of the natural substrate S of DTP; and d) selecting the E. coli cells [P-:: X*] which have survived stage c) in which the mutants X* are capable of carrying out the biosynthesis of the product P from the substrate S.