Open AccessThe contribution of metal ions to the conformational stability of ribonuclease T 1
Author(s) -
Deswarte Joeri,
De Vos Stefan,
Langhorst Ulrike,
Steyaert Jan,
Loris Remy
Publication year - 2001
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2001.02310.x
Subject(s) - metal ions in aqueous solution , ion , metal , crystallography , chemistry , carboxylate , crystal structure , divalent , ribonuclease , inorganic chemistry , stereochemistry , rna , biochemistry , organic chemistry , gene
In the crystalline state, ribonuclease T 1 binds calcium ions at different lattice‐dependent positions. In solution, its conformational stability is also remarkably increased in the presence of divalent metal ions. Combining urea unfolding studies and X‐ray crystallography, we compared the presence of several metal ions at specific sites in the protein to their contribution to the overall stabilizing effect in solution. We constructed thermodynamic cycles involving particular metal ions and specific carboxylate functions. The resulting coupling energies indicate that some (but not all) metal ions found at lattice contacts in crystal structures may indeed significantly contribute to stability enhancement in the presence of metal ions in solution.