CLONING AND EXPRESSION OF ESCHERICHIA-COLI 5'-METHYLTHIOADENOSINE S-ADENOSYLHOMOCYSTEINE NUCLEOSIDASE - IDENTIFICATION OF THE PFS GENE-PRODUCT/

The enzyme 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (EC 3.2.2.9) is responsible for cleavage of the glycosidic bond in bot h 5'-methylthioadenosine (MTA) and S-adenosylhomocysteine (SAH). Based on amino acid sequence analysis of this enzyme from Klebsiella. we re cently speculated that an open reading frame found in E. coli (designa ted pfs) encoded MTA/SAH nucleosidase. To explore this possibility, we amplified, cloned, and expressed the complete pfs gene from E, coli g enomic DNA. The recombinant protein exhibited a molecular weight and M ichaelis constants for MTA that are in agreement with those reported f or native enzyme, From this biochemical evidence we confirm our origin al assignment of the pfs gene as encoding MTA/SAH nucleosidase. (C) 19 98 Elsevier Science B.V.