Origin recognition complex subunit 6, also known as ORC6, belongs to the origin recognition complex (ORC). ORC is a highly conserved heterohexameric protein complex that associates with DNA at or near sites of initiation of DNA replication. All six ORC subunits are essential for initiation of DNA replication, and ORC may be involved in regulation of gene expression in response to stress. ORC6 is also expressed constantly throughout the cell cycle. ORC2, ORC3, ORC4 and ORC5 form a core complex upon which ORC6 and ORC1 assemble. Recombinant human ORC6 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.