Allosteric formulation of thermal transitions in macromolecules, including effects of ligand binding and oligomerization

Authors

  • Charles H. Robert,

    1. Department of Chemistry and Biochemistry, University of Colorado, Campus Box 215, Boulder, Colorado 80309
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  • Alfredo Colosimo,

    1. Department of Chemistry and Biochemistry, University of Colorado, Campus Box 215, Boulder, Colorado 80309
    Current affiliation:
    1. Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Università di Tor Vergata, Via Orazio Raimondo 00173 Roma, Italy
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  • Stanley J. Gill

    Corresponding author
    1. Department of Chemistry and Biochemistry, University of Colorado, Campus Box 215, Boulder, Colorado 80309
    • Department of Chemistry and Biochemistry, University of Colorado, Campus Box 215, Boulder, Colorado 80309
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Abstract

We examine the effects of concentration (aggregation), buffers, and ligation, under conditions of either constant ligand activity or limited total amount of ligand, upon thermal denaturation of macromolecules as measured by scanning calorimetry. In doing so we utilize and extend an earlier generalized allosteric treatment [S. J. Gill, B. Richey, G. Bishop, and J. Wyman (1985) Biophys. Chem.21, 1–14], applicable to ligand binding, enthalpy changes, and volume changes in a macromolecular system. The approach is contrasted with formulations based on the idea of structural domains. We show how information from the full scanning calorimetric curves can be utilized in arriving at and testing appropriate models for observed behavior in selected examples.

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