title: Crystal structures of two active proliferating cell nuclear antigens (PCNAs) encoded by Thermococcus kodakaraensis.
abstract: Proliferating cell nuclear antigen (PCNA) is a ring-shaped protein that encircles duplex DNA and plays an essential role in many DNA metabolic processes in archaea and eukarya. The eukaryotic and euryarchaea genomes contain a single gene encoding for PCNA. Interestingly, the genome of the euryarchaeon Thermococcus kodakaraensis contains two PCNA-encoding genes (TK0535 and TK0582), making it unique among the euryarchaea kingdom. It is shown here that the two T. kodakaraensis PCNA proteins support processive DNA synthesis by the polymerase. Both proteins form trimeric structures with characteristics similar to those of other archaeal and eukaryal PCNA proteins. One of the notable differences between the TK0535 and TK0582 rings is that the interfaces are different, resulting in different stabilities for the two trimers. The possible implications of these observations for PCNA functions are discussed.
authors.affiliation: National Institute of Standards and Technology, 9600 Gudelsky Drive, Rockville, MD 20850, USA.
authors.forename: Jane E
authors.initials: JE
authors.lastname: Ladner
authors.forename: Miao
authors.initials: M
authors.lastname: Pan
authors.forename: Jerard
authors.initials: J
authors.lastname: Hurwitz
authors.forename: Zvi
authors.initials: Z
authors.lastname: Kelman
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003460:Crystallization; D017931:DNA Primers / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000648:ultrastructure*; D013045:Species Specificity; D019712:Thermococcus / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D018809:Proliferating Cell Nuclear Antigen