Nucleotide sequence of the Escherichia coli replication gene dnaZX.

The Escherichia coli 2.2 kilobase dnaZX region contains one 1929 nucleotide reading frame which directs the synthesis of two protein products involved in DNA polymerization. The larger consists of 643 amino acids in a deduced 71,114 dalton chain which could be the tau subunit of DNA polymerase III. The smaller, the DNA polymerase III gamma subunit, is encoded by the same reading frame as the larger. The dnaZX sequence contains a region homologous to ATP binding sites, suggesting that these replication factors are adenine nucleotide binding proteins.