Atreya Hanudatta S, Mukherjee Sulakshana, Chary Kandala V R, Lee Yong-Min, Luchinat Claudio
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai-400005 India.
Protein Sci. 2003 Mar;12(3):412-25. doi: 10.1110/ps.0225603.
We have studied the displacement of Ca(2+)by the trivalent lanthanide ions (Yb(3+)) in a protozoan (Entamoeba histolytica) Ca(2+)-binding protein (EhCaBP), by NMR and thermodynamics. We have demonstrated, for the first time, how one can use in a combined fashion the utility of NMR and thermodynamics to have an insight to the relative binding specificities/affinity between Ca(2+) and Yb(3+). As revealed by the titration experiments, Yb(3+) displaces Ca(2+) from the four metal binding sites present in EhCaBP in a sequential manner. The study provides a structural origin for such a sequential Ca(2+) displacement by Yb(3+) in EhCaBP.
我们通过核磁共振（NMR）和热力学方法，研究了原生动物（溶组织内阿米巴）钙结合蛋白（EhCaBP）中三价镧系离子（Yb(3+)）对Ca(2+)的置换情况。我们首次展示了如何以联合的方式利用NMR和热力学的效用，来深入了解Ca(2+)和Yb(3+)之间的相对结合特异性/亲和力。滴定实验表明，Yb(3+)以顺序方式从EhCaBP中存在的四个金属结合位点置换Ca(2+)。该研究为EhCaBP中Yb(3+)对Ca(2+)的这种顺序置换提供了结构根源。
