The Use of the Free Metal – Temperature ‘Phase Dia

Authors: Sergei E Permyakov Eugene A Permyakov

Publish Date: 2006/11/30

Volume: 26, Issue: 1, Pages: 1-12

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Abstract

Typical physicochemical studies of metal binding proteins are usually aimed at determination of the metal binding constant K for a native protein K n while the significance of the K value for the thermally denatured protein K u is usually underestimated Meanwhile metal binding induced shift of thermal denaturation transition of a single site metal binding protein is defined by K n to K u ratio implying that knowledge of both K values is required for full characterization of the system In the present work the most universal approach to the studies of single site metal binding proteins namely construction of a protein “phase diagram” in coordinates of free metal ion concentration – temperature is considered in detail The detailed algorithm of construction of the phase diagrams along with underlying mathematic procedures developed here may be of use for studies of other simple proteintarget type systems where target represents low molecular weight ligand Analysis of the simplest proteinligand system reveals that thermodynamic properties of apoprotein dictate the maximal possible increase of its affinity to any simple ligand upon thermal denaturation of the protein Experimental and general problems coupled with the use of the phase diagrams are discussedWe are indebted to Prof R Kretsinger and Dr VN Uversky for very useful discussion of our work and correction of the manuscript This work was supported by grants from the Programs of the Russian Academy of Sciences “Fundamental science for medicine” and “Molecular and cellular biology” Grant 02442117542 of the Russian Federal Agency for Science and Innovations Grant 040497322 of the Russian Fund for Basic Research and individual grants to SEP from the “Russian Science Support Foundation” RUB2010001PU05 CRDF and the Visby Programme of the Swedish Institute

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