doi:10.1155/2012/951010 Review Article Rings in the Extreme: PCNA Interactions and Adaptations in the Archaea

Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Biochemical and structural analysis of archaeal proteins has enabled us to gain great insight into many eukaryotic processes, simultaneously offering fascinating glimpses into the adaptation and evolution of proteins at the extremes of life. The archaeal PCNAs, central to DNA replication and repair, are no exception. Characterisation of the proteins alone, and in complex with both peptides and protein binding partners, has demonstrated the diversity and subtlety in the regulatory role of these sliding clamps. Equally, studies have provided valuable detailed insight into the adaptation of protein interactions and mechanisms that are necessary for life in extreme environments. 1. PCNA Plays a Central Role in the Regulation of DNA Replication and Repair Sliding clamps, including the proliferating cell nuclear anti-gen (PCNA), are central to DNA replication processes. These molecules encircle DNA, thereby forming a platform for DNA polymerases to achieve the high processivity required for DNA replication. Additionally, many other molecule