Component of the origin recognition complex (ORC) that binds origins of replication and thus may regulate the initiation of DNA replication (Probable). DNA-binding may not be ATP-dependent (PubMed:19633266). In a SIR2A/Sir2-dependent manner, binds to and silences telomers and subtelomeric repeat regions (TAREs) (PubMed:18525026, PubMed:22379140, PubMed:24018145). In a SIR2A/Sir2-dependent manner, binds to promoters of var genes localized next to TAREs resulting in their silencing (PubMed:22379140). ATP + H2O = ADP + H(+) + phosphate Component of the origin recognition complex (ORC) (By similarity). Interacts (via PIP-box) with PCNA1; the interaction occurs during DNA replication in trophozoites (PubMed:18554328, PubMed:19633266). At the late ring stage/early trophozoites, co-localizes with SIR2A/Sir2 to telomeres and subtelomeric regions (TAREs) in the nuclear periphery (PubMed:18525026, PubMed:22379140, PubMed:26094711). Also, partially localizes to the nucleolus (PubMed:18525026). In trophozoites and early schizonts localizes throughout the nucleus (PubMed:18525026, PubMed:26094711). During early-to mid replicating trophozoite stages, colocalizes with PCNA1 and ORC1 to distinct nuclear foci which probably are DNA replication origin sites (PubMed:18554328, PubMed:19633266). In schizonts, relocalizes to the nuclear periphery and cytoplasm (PubMed:18525026, PubMed:26094711). In late schizonts, expression decreases probably due to proteosome-mediated degradation (PubMed:18554328, PubMed:26094711). Expressed during the asexual blood stage, specifically during the late trophozoite and early schizont stages (at protein level) (PubMed:16216221, PubMed:18525026, PubMed:18554328, PubMed:19633266, PubMed:22379140, PubMed:26094711). Some expression has been found also at the ring stage (at protein level) (PubMed:18525026, PubMed:18554328, PubMed:22379140, PubMed:26094711). Highly expressed during the sexual blood stage (PubMed:12543146). The N-terminal domain binds telomeric DNA and is required for the silencing of telomers and var genes. The C-terminal domain binds ATP and is required for the binding to DNA replication origin sites. Leucine heptad repeats are essential for the binding to telomeric DNA. In schizonts, may be phosphorylated by PK5; phosphorylation leads to ORC1 dissociation from the telomeres and var gene promoters, translocation to the cytoplasm, where it is degraded by the proteasome. Possible candidate for an effective malaria vaccine as determined by epitope response in sera. Belongs to the ORC1 family.