ALG-2 divalent-ion affinity: Calorimetric analysis of the des23 versions reveals high-affinity site for Mg2 +

- ALG-2des23wt binds Ca2 + ions sequentially, with no apparent cooperativity.
- ALG-2des23ΔGF122 binds Ca2 + with evidence of inter-subunit cooperativity.
- Both isoforms possess a high-affinity (K > 5 × 104 M− 1) binding-site for Mg2 +.
- The high-affinity Mg2 + site exhibits atypically low affinity for Ca2 +.
- The Mg2 +-binding site is believed to reside in the EF5 binding loop.