Specificity and Function of Archaeal DNA Replication Initiator Proteins
Rachel Y. Samson,
Yanqun Xu,
Catarina Gadelha,
Todd A. Stone,
Jamal N. Faqiri,
Dongfang Li,
Nan Qin,
Fei Pu,
Yun Xiang Liang,
Qunxin She,
Stephen D. Bell
Affiliations
Rachel Y. Samson
Sir William Dunn School of Pathology, Oxford University, South Parks Road, Oxford OX1 3RE, UK
Yanqun Xu
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Catarina Gadelha
Sir William Dunn School of Pathology, Oxford University, South Parks Road, Oxford OX1 3RE, UK
Todd A. Stone
Molecular and Cellular Biochemistry Department, Department of Biology, Indiana University, Simon Hall, 212 South Hawthorne Drive, Bloomington, IN 47405, USA
Jamal N. Faqiri
Archaeal Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
Dongfang Li
BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, China
Nan Qin
BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, China
Fei Pu
BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, China
Yun Xiang Liang
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Qunxin She
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Stephen D. Bell
Sir William Dunn School of Pathology, Oxford University, South Parks Road, Oxford OX1 3RE, UK
Chromosomes with multiple DNA replication origins are a hallmark of Eukaryotes and some Archaea. All eukaryal nuclear replication origins are defined by the origin recognition complex (ORC) that recruits the replicative helicase MCM(2-7) via Cdc6 and Cdt1. We find that the three origins in the single chromosome of the archaeon Sulfolobus islandicus are specified by distinct initiation factors. While two origins are dependent on archaeal homologs of eukaryal Orc1 and Cdc6, the third origin is instead reliant on an archaeal Cdt1 homolog. We exploit the nonessential nature of the orc1-1 gene to investigate the role of ATP binding and hydrolysis in initiator function in vivo and in vitro. We find that the ATP-bound form of Orc1-1 is proficient for replication and implicates hydrolysis of ATP in downregulation of origin activity. Finally, we reveal that ATP and DNA binding by Orc1-1 remodels the protein’s structure rather than that of the DNA template.
