The unstructured C-terminus of the tau subunit of Escherichia coli DNA polymerase III holoenzyme is the site of interaction with the alpha subunit.

ABSTRACT: The tau subunit of Escherichia coli DNA polymerase III holoenzyme interacts with the alpha subunit through its C-terminal Domain V, tau(C)16. We show that the extreme C-terminal region of tau(C)16 constitutes the site of interaction with alpha. The tau(C)16 domain, but not a derivative of it with a C-terminal deletion of seven residues (tau(C)16Delta7), forms an isolable complex with alpha. Surface plasmon resonance measurements were used to determine the dissociation constant (K(D)) of the alpha-tau(C)16 complex to be approximately 260 pM. Competition with immobilized tau(C)16 by tau(C)16 derivatives for binding to alpha gave values of K(D) of 7 muM for the alpha-tau(C)16Delta7 complex. Low-level expression of the genes encoding tau(C)16 and tau(C)16triangle up7, but not tau(C)16Delta11,

SUBMITTER: Jergic S 

PROVIDER: S-EPMC1888804 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature