DNA-SEQUENCING AND EXPRESSION OF THE FORMYL COENZYME-A TRANSFERASE GENE, FRC, FROM OXALOBACTER-FORMIGENES

Oxalic acid, a highly toxic by-product of metabolism is catabolized by a limited number of bacterial species utilizing an activation-decarbo xylation reaction which yields formate and CO2. frc, the gene encoding formyI coenzyme A transferase, an enzyme which transfers a coenzyme A moiety to activate oxalic acid, was cloned from the bacterium Oxaloba cter formigenes. DNA sequencing revealed a single open reading frame o f 1,284 bp capable of encoding a 428-amino-acid protein. A presumed pr omoter region and a rho-independent termination sequence suggest that this gene is part of a monocistronic operon. A PCR fragment containing the open reading frame, when overexpressed in Escherichia coli, produ ced a product exhibiting enzymatic activity similar to the purified na tive enzyme. With this, the two genes necessary for bacterial cataboli sm of oxalate, frc and oxc, have now been cloned, sequenced, and expre ssed.