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Communication between subunits within an archaeal clamp-loader complex.

ABSTRACT: We have investigated the communication between subunits in replication factor C (RFC) from Archaeoglobus fulgidus. Mutation of the proposed arginine finger in the small subunits results in a complex that can still bind ATP but has impaired clamp-loading activity, a process that normally only requires binding of nucleotide. The small subunit alone forms a hexameric ring that is six-fold symmetric in the absence of ATP. However, this symmetry is broken when the nucleotide is bound to the complex. A conformational change associated with nucleotide binding may relate to the opening of PCNA rings by RFC during the loading reaction. The structures also reveal the importance of the N-terminal helix of each subunit at the ATP-binding site. Analysis of mutant protein complexes containing subunits lacking this N-terminal helix reveals key distinct regulatory roles during clamp loading that are different for the large and small subunits in the RFC complex.

SUBMITTER: Seybert A

PROVIDER: S-EPMC1462970 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature

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Communication between subunits within an archaeal clamp-loader complex.

Seybert Anja A Singleton Martin R MR Cook Nicola N Hall David R DR Wigley Dale B DB

The EMBO journal 20060420 10

We have investigated the communication between subunits in replication factor C (RFC) from Archaeoglobus fulgidus. Mutation of the proposed arginine finger in the small subunits results in a complex that can still bind ATP but has impaired clamp-loading activity, a process that normally only requires binding of nucleotide. The small subunit alone forms a hexameric ring that is six-fold symmetric in the absence of ATP. However, this symmetry is broken when the nucleotide is bound to the complex. ...[more]

PMID: 16628222

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