title: The GINS complex from the thermophilic archaeon, Thermoplasma acidophilum may function as a homotetramer in DNA replication.
abstract: The eukaryotic GINS heterotetramer, consisting of Sld5, Psf1, Psf2, and Psf3, participates in "CMG complex" formation with mini-chromosome maintenance (MCM) and Cdc45 as a key component of a replicative helicase. There are only two homologs of the GINS proteins in Archaea, and these proteins, Gins51 and Gins23, form a heterotetrameric GINS with a 2:2 molar ratio. The Pyrococcus furiosus GINS stimulates the ATPase and helicase activities of its cognate MCM, whereas the Sulfolobus solfataricus GINS does not affect those activities of its cognate MCM, although the proteins bind each other. Intriguingly, Thermoplasma acidophilum, as well as many euryarchaea, have only one gene encoding the sequence homologous to that of archaeal Gins protein (Gins51) on the genome. In this study, we investigated the biochemical properties of the gene product (TaGins51). A gel filtration and electron microscopy revealed that TaGins51 forms a homotetramer. A physical interaction between TaGins51 and TaMcm was detected by a surface plasmon resonance analysis. Unexpectedly, TaGins51 inhibited the ATPase activity, but did not affect the helicase activity of its cognate MCM. These results suggest that another factor is required to form a stable helicase complex with MCM and GINS at the replication fork in T. acidophilum cells.
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ogino
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ishino
authors.forename: Kouta
authors.initials: K
authors.lastname: Mayanagi
authors.forename: Gyri Teien
authors.initials: GT
authors.lastname: Haugland
authors.forename: Nils-Kåre
authors.initials: NK
authors.lastname: Birkeland
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamagishi
authors.forename: Yoshizumi
authors.initials: Y
authors.lastname: Ishino
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology*; D019641:DNA, Archaeal / Q000096:biosynthesis* / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D013822:Thermoplasma / Q000201:enzymology* / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D019641:DNA, Archaeal; D004268:DNA-Binding Proteins; D009097:Multienzyme Complexes