A novel serralysin metalloprotease from Deinococcus radiodurans

Abstract

A hypothetical protein (DR2310) from the radiation resistant organism Deinococcus radiodurans harbors highly conserved Zn⁺²-binding (HEXXH) domain and Met-turn (SVMSY), characteristic of the serralysin family of secreted metalloproteases from Gram negative bacteria. Deletion mutagenesis of DR2310 confirmed that the ORF is expressed in Deinococcus radiodurans as a secreted protease of 85 kDa. Biochemical analysis revealed DR2310 to be a Ca⁺² and Zn⁺²-requiring metalloprotease. Unique features such as a long N-terminus, replacement of the highly conserved C-terminal glycine rich Ca⁺²-binding repeats with a single N-terminal aspartate rich eukaryotic thrombospondin type-3 Ca⁺²-binding repeat and absence of C-terminal secretion signals make it a novel member of serralysin family. This is the first report of a functional serralysin family metalloprotease from a Gram positive organism.