A single amino acid change at the signal sequence of a Cl-amylase gene truncates it's enzyme translocation in E. coli = Recombinant Cl-amylase의 세포내 수송에 있어서 Signal sequence의 역할

Abstract

The possible signal sequence capable of transporting the Cl-amylase from B. circu-lans has been analyzed with in vitro mutagenesis techniques. A residue in the NH2-terminal region near to the postulated cleavase site was changed by site-directed mutagenesis from a serine into proline and threonine. Comparison of Cl-amylase acitivity outside and inside the cell in strains containing the cloned wild type and mutagenised genes showed that this single amino acid prevents largely the translocation of the enzyme in the periplasmic space: in transformed E. coli the proline -mutant Cl-amylase showed 5% secretion of wild type Cl-amylase and threonine-mutant Cl-amylase.