Summary of divalent cation studies.

A literature review was conducted on previously published studies where divalent cations other than Mg2+ were utilized in type IA topoisomerase DNA relaxation assays. The findings are summarized herein. Methanosarcina acetivorans C2A, Mac; Drosophila melanogaster, Dme; Escherichia coli, Eco; Fervidobacterium islandicum, Fis; Homo sapiens, Hsa; Methylophaga sp. strain 3, Met; Nicotiana tabacum, Nta; Rhodobacter capsulatus, Rca; Staphylococcus aureus, Sau; Sulfolobus solfataricus, Sso; D, data not shown; S, M2+SO4 used in place of M2+Cl2; Y, high activity; M, moderate activity; L, low activity; N, no activity.