This family consists of several bacterial phosphonate metabolism protein PhnG sequences. In Escherichia coli, the phn operon encodes proteins responsible for the uptake and breakdown of phosphonates. The exact function of PhnG is unknown, however it is thought likely that along with six other proteins PhnG makes up the the C-P (carbon-phosphorus) lyase [1].

1: Rhizobium (Sinorhizobium) meliloti phn genes: characterization and identification of their protein products. Parker GF, Higgins TP, Hawkes T, Robson RL; J Bacteriol 1999;181:389-395. PMID:9882650