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Structure of the PolIII?-?c-DNA complex suggests an atomic model of the replisome.

ABSTRACT: The C-terminal domain (CTD) of the ? subunit of the clamp loader (?c) binds to both the DnaB helicase and the DNA polymerase III ? subunit (PolIII?), and determines their relative positions and orientations on the leading and lagging strands. Here, we present a 3.2 Å resolution structure of Thermus aquaticus PolIII? in complex with ?c and a DNA substrate. The structure reveals that the CTD of ?c interacts with the CTD of PolIII? through its C-terminal helix and the adjacent loop. Additionally, in this complex PolIII? displays an open conformation that includes the reorientations of the oligonucleotide-binding fold and the thumb domain, which may be an indirect result of crystal packing due to the presence of the ?c. Nevertheless, the position of the ?c on PolIII? allows us to suggest an approximate model for how the PolIII? is oriented and positioned on the DnaB helicase.

SUBMITTER: Liu B

PROVIDER: S-EPMC3652607 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature

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Structure of the PolIIIα-τc-DNA complex suggests an atomic model of the replisome.

Liu Bin B Lin Jinzhong J Steitz Thomas A TA

Structure (London, England : 1993) 20130307 4

The C-terminal domain (CTD) of the τ subunit of the clamp loader (τc) binds to both the DnaB helicase and the DNA polymerase III α subunit (PolIIIα), and determines their relative positions and orientations on the leading and lagging strands. Here, we present a 3.2 Å resolution structure of Thermus aquaticus PolIIIα in complex with τc and a DNA substrate. The structure reveals that the CTD of τc interacts with the CTD of PolIIIα through its C-terminal helix and the adjacent loop. Additionally, i ...[more]

PMID: 23478062

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