Cervimycin C is the major component of an antibiotic complex produced by Streptomyces tendae HKI-179 consisting of a tetracycline-type aglycon, six tridesoxysugars and a rare dimethylmalonyl moiety. The biosynthetic origin of cervimycin was studied by molecular studies and feeding experiments, which reveal that the dimethylmalonate unit is not derived from malonate, but from valine.