DNA POLYMERASE-III ACCESSORY PROTEINS .1. HOLA AND HOLB ENCODING DELTA AND DELTA'

The genes encoding the delta and delta' subunits of the 10-subunit Esc herichia coli replicase, DNA polymerase III holoenzyme, have been iden tified and sequenced. The holA gene encoding delta is located downstre am of rlpB at 15.2 min and predicts a 38.7 kda protein. The holB gene encoding delta' is located at 24.3 min and predicts a 36.9-kDa protein . Hence the delta and delta' subunits are unrelated proteins encoded b y separate genes. The genes have been used to express and purify delta and delta' in quantity. The predicted amino acid sequence of delta' i s homologous to the sequences of the tau and gamma subunits revealing a large amount of structural redundancy within the holoenzyme.