Figure 2.

Effect of Ca²⁺ on the stability of the reconstituted B-RG-II complex. Boric acid (50 mm) and monomeric RG-II (5 mm) were incubated in 50 mm sodium acetate buffer (pH 4.0) with (○) or without (•) 50 mm CaCl₂. After 20 h, the reaction mixture was diluted 10 times with the acetate buffer and free boric acid and Ca²⁺ were removed with Amberlite IRA-743 resin (SO₄²⁻ form) and Dowex 50W-X8 resin (Na⁺ form), respectively. At intervals an aliquot (10 μL) was subjected to size-exclusion HPLC with a refractive index detector. The figures on the vertical axis indicate the mole percentage of RG-II converted into the dimeric form.