Proteins in this family are uncharacterised, but have been identified as members of a gene cluster for the synthesis of the tetramic-acid antibiotic streptolydigin, which inhibits bacterial RNA polymerase (RNAP) [1].

1: Inhibition of bacterial RNA polymerase by streptolydigin: stabilization of a straight-bridge-helix active-center conformation. Tuske S, Sarafianos SG, Wang X, Hudson B, Sineva E, Mukhopadhyay J, Birktoft JJ, Leroy O, Ismail S, Clark AD Jr, Dharia C, Napoli A, Laptenko O, Lee J, Borukhov S, Ebright RH, Arnold E; Cell. 2005;122:541-552. PMID:16122422