Cloning of D-hydantoinase Gene from Pseudomonas and Its Expression in E.coli / 中国药科大学学报

ABSTRACT

AIM　The purpose is to construct D-hydantoinase genetic engineering strain for the purpose of the industrial production of D-p-hydroxyphenylglycine. METHODS　D-hydantoinase gene was created from Pseudomonas putida 9801 by PCR technique and inserted into pMD18-T vector. The recombinant plasmid was transformed into several Escherichia coli strains. The positive transformants with D-hydantoinase activity were obtained by the two step screening, digoxigenin DNA labeling in situ hybridization and D-hydantoinase activity assay. RESULTS　The D-hydantoinase activity of the genetic engineering strain E.coli BL21/pMD-dht was 1700 U*L-1 and increased as high as 8 times compared with those of wild-type strain Pseudomonas putida 9801. The subunit molecular weight of recombinant D-hydantoinase was about 53 kDa measured by SDS-PAGE. The amount of the recombinant D-hydantoinase was about 20 percent of total bacterial soluble proteins. CONCLUSION　The genetic engineering strain E.coli BL21/pMD-dht possesses the initial industrial production prospects.