This family contains many hypothetical bacterial proteins. It has been identified as a member of the PD-(D/E)XK nuclease superfamily through transitive meta profile searches [1]. DUF1703 has the predicted secondary structure pattern of the restriction endonuclease-like fold core and contains an additional beta-strand at the C-terminus [1].

1: Realm of PD-(D/E)XK nuclease superfamily revisited: detection of novel families with modified transitive meta profile searches. Knizewski L, Kinch LN, Grishin NV, Rychlewski L, Ginalski K; BMC Struct Biol. 2007;7:40. PMID:17584917