Table 2.

Summary of metal binding sites^a

Type	Mn2+	Co2+	Ni2+	Cs+	Rb+
Total	45	43	47	12	5
DNA	43	37	37	9	3
major	18	27	27
major-MH	5	7	7
minor				9	3
minor-MH	17	3	3
PO4	3
Histone	2	6	10	3	2
His		3	3
His+Asp/Glu		1	2
Asp/Glu	1	2	5
peptide C=O	1			3	2

^aInteraction with DNA entails direct coordination or association of the metal hydrate (MH).

Protein binding is characterized as coordination involving histidine, acidic side chains or a combination of the two amino acid types, or coordination exclusively with peptide carbonyl groups.

Data for Mn²⁺ association are from an earlier study (14).