A type III polyketide synthase from Rhizobium etli condenses malonyl CoAs to a heptaketide pyrone with unusually high catalytic efficiency.

A novel type III polyketide synthase (RePKS) from Rhizobium etli produced a heptaketide pyrone using acetyl-CoA and six molecules of malonyl-CoA. Its catalytic efficiency (k(cat)/K(m) = 5230 mM(-1) min(-1)) for malonyl CoA was found to be the highest ever reported. Molecular dynamics studies revealed the unique features of RePKS.