Identification, isolation, and characterization of the structural gene encoding the delta' subunit of Escherichia coli DNA polymerase III holoenzyme

J Bacteriol. 1993 Jun;175(12):3812-22. doi: 10.1128/jb.175.12.3812-3822.1993.


The gene encoding the delta' subunit of DNA polymerase III holoenzyme, designated holB, was cloned by a strategy in which peptide sequence was used to derive a DNA hybridization probe. The gene maps to 24.95 centisomes of the chromosome. Sequencing of holB revealed a 1,002-bp open reading frame predicted to produce a 36,936-Da protein. The gene has a ribosome-binding site and promoter that are highly similar to the consensus sequences and is flanked by two potential open reading frames. Protein sequence analysis of delta' revealed a high degree of similarity to the dnaX gene products of Escherichia coli and Bacillus subtilis, including one stretch of 10 identical amino acid residues. A lesser degree of similarity to the gene 44 protein of bacteriophage T4 and the 40-kDa protein of the A1 complex (replication factor C) of HeLa cells was seen. The gene, when placed into a tac promoter-based expression plasmid, directed expression of two proteins of similar size. By immunodetection with anti-holoenzyme immunoglobulin G, both proteins are judged to be products of holB.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Base Sequence
  • Chromosome Mapping
  • Cloning, Molecular
  • Codon
  • DNA Polymerase III / genetics*
  • DNA, Bacterial / genetics
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Genes, Bacterial*
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides / chemistry
  • Peptide Fragments / chemistry
  • Polymerase Chain Reaction
  • Recombinant Proteins / metabolism
  • Restriction Mapping


  • Bacterial Proteins
  • Codon
  • DNA, Bacterial
  • Oligodeoxyribonucleotides
  • Peptide Fragments
  • Recombinant Proteins
  • DNA Polymerase III

Associated data

  • GENBANK/L01483