Specific in vivo cleavage of D-serine deaminase and properties of tetrameric polypeptide aggregates of the fragments

Abstract

The primary D-serine deaminase (D-serine dehydratase, EC 4.2.1.14) of Escherichia coli K-12 is unstable within the cell. The protein, a single polypeptide chain, is cleaved at a lysine residue by a cellular proteolytic activity. Fragments containing the active site then aggregate into tetramers, which retain substrate affinity and show very low catalytic activity. Such degradations may represent an evolutionary mechanism for the generation of new enzymes.