Résumé
The two pabAB genes encoding aminodeoxychorismate synthase(ADC synthase)from a L-serine producing strain Corynebacterium glutamicum SYPS-062 and model strain Corynebacterium glutamicum ATCC 13032 were ampilified by PCR.The result of nucleotide sequence analysis showed that both pabAB fragments were 1863bp,encoding 620 amino acids.16 bases differences that resulted in the changes of 7 amino acids were found in the pabAB of SYPS-062.The two pabAB were inserted into pET-28a to yield the recombinant expression vector pET-28a-pabAB and then transfromed into BL21(DE3).Upon IPTG induction,soluble ADC synthase was over-produced by E.coli BL21(DE3)harboring the expression construct.Recombinant ADC synthase purified by Ni-NTA affinity chromatography showed a single band about 67kDa on SDS-PAGE gel,and activity of aminodeoxychorismate synthase analysis show that the enzyme specific activity of SYPS-062 is 46.6% lower than ATCC 13032.