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Structural basis for sequential displacement of Ca 2+ by Yb 3+ in a protozoan EF‐hand calcium binding protein
Author(s) -
Atreya Hanudatta S.,
Mukherjee Sulakshana,
Chary Kandala V.R.,
Lee YongMin,
Luchinat Claudio
Publication year - 2003
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0225603
Subject(s) - calcium , physics , displacement (psychology) , chemistry , crystallography , biophysics , biology , psychology , organic chemistry , psychotherapist
Abstract We have studied the displacement of Ca 2+ by the trivalent lanthanide ions (Yb 3+ ) in a protozoan ( Entamoeba histolytica ) Ca 2+ ‐binding protein ( Eh CaBP), 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 Eh CaBP in a sequential manner. The study provides a structural origin for such a sequential Ca 2+ displacement by Yb 3+ in Eh CaBP.