<p> DNA polymerase III delta (holA, <db_xref db="EC" dbkey="2.7.7.7"/>) and delta prime (holB) subunits are distinct proteins encoded by separate genes. The delta prime subunit (holB) exhibits sequence homology to the tau and gamma subunits (dnaX), but the delta subunit (holA) does not demonstrate this same homology with dnaX. The delta, delta prime, gamma, chi and psi subunits form the gamma complex sub-assembly of DNA polymerase III holoenzyme, which couples ATP to assemble the ring-shaped beta subunit around DNA forming a DNA sliding clamp. Both delta and delta prime are monomeric in their native state, and they bind each other tightly to form a 1:1 complex. Neither delta nor delta prime alone binds tightly to the gamma subunit [<cite idref="PUB00007895"/>]. </p>