Component of the origin recognition complex (ORC) that binds origins of replication. It has a role in both chromosomal replication and mating type transcriptional silencing. Binds to the ARS consensus sequence (ACS) of origins of replication. Component of the origin recognition complex (ORC) composed of at least ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. Interacts with MCM10 and TAH11. The N-terminus is dedicated to mating-type repression. Present with 3930 molecules/cell in log phase SD medium. Belongs to the ORC1 family.