Cloning the polB gene of Escherichia coli and identification of its product.

摘要: Using an in vivo mini-Mu cloning system, we have cloned the polB gene of Escherichia coli into multicopy plasmid, pUC18. A chromosomal insert 4.9 kilobases gave 30-40-fold overproduction DNA polymerase II, and cells containing plasmid showed normal growth. The restriction pattern does not match that either polA or polC gene. Plasmid-directed protein synthesis demonstrates peptides 99 82 kDa which are expressed by derivative plasmids without II activity. It appears from situ gel assays high performance liquid chromatography 82- 55-kDa proteins derived 99-kDa degradation, but all retain I III antibody inhibit reaction partially purified does. By criteria gene, molecular weight protein, inhibition reaction, can be demonstrated to a distinct polymerase.