Coordinate binding of ATP and origin DNA regulates the ATPase activity of the origin recognition complex.
The Origin Recognition Complex (ORC) is a six-protein assembly that specifies the sites of DNA replication initiation in S. cerevisiae. Origin recognition by ORC requires ATP. Here, we demonstrate that two subunits, Orc1p and Orc5p, bind ATP and that Orc1p also hydrolyzes ATP. ATP binding and hydrolysis by Orc1p are both regulated by origin DNA in a sequence-specific manner. ATP binding to Orc1p, but not ATP hydrolysis, is responsible for the ATP dependence of the ORC-origin interaction, indicating that ATP is a cofactor that locks ORC on origin DNA. These data demonstrate that occupancy of the Orc1p ATP-binding site has a profound effect on ORC function and that ATP hydrolysis by Orc1p has the potential to drive transitions between different functional states of ORC.
Klemm
R D
RD
Massachusetts Institute of Technology, Department of Biology, Cambridge 02139, USA.
Austin
R J
RJ
Bell
S P
SP
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D004261:DNA Replication; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D006868:Hydrolysis; D016296:Mutagenesis / Q000502:physiology; D051738:Origin Recognition Complex; D018741:Replication Origin / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D051738:Origin Recognition Complex; D012097:Repressor Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases