We have obtained an experimental estimate of the free energy change associated with variations at the interface between protein subunits, a subject that has raised considerable interest since the concept of accessible surface area was introduced by Lee and Richards [Lee, E. & Richards, F. M. (1971) J. Mol. Biol. 55, 379-400], We determined by analytical ultracentrifugation the dimer-tetramer equilibrium constant of five single and three double mutants of human Kb, One mutation is at the stationary alpha(1) beta(1) interface, and all of the others are at the sliding alpha(1) beta(2) interface where cleavage of the tetramer into dimers and ligand-linked allosteric changes are known to occur. A surprisingly good linear correlation between the change in the free energy of association of the mutants and the change in buried hydrophobic surface area was obtained, after corrections for the energetic cost of losing steric complementarity at the ap dimer interface, The slope yields an interface stabilization free energy of -15 +/- 1.2 cal/mol upon burial of 1 Angstrom(2) of hydrophobic surface, in very good agreement with the theoretical estimate given by Eisenberg and McLachlan [Eisenberg, D. & McLachlan, A. D. (1986) Nature (London) 319, 199-203].

Free energy of burying hydrophobic residues in the interface between protein subunits / Vallone, Beatrice; Miele, Adriana Erica; P., Vecchini; Chiancone, Emilia; Brunori, Maurizio. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 0027-8424. - STAMPA. - 95:11(1998), pp. 6103-6107. [10.1073/pnas.95.11.6103]

Free energy of burying hydrophobic residues in the interface between protein subunits

VALLONE, Beatrice;MIELE, Adriana Erica;CHIANCONE, Emilia;BRUNORI, Maurizio
1998

Abstract

We have obtained an experimental estimate of the free energy change associated with variations at the interface between protein subunits, a subject that has raised considerable interest since the concept of accessible surface area was introduced by Lee and Richards [Lee, E. & Richards, F. M. (1971) J. Mol. Biol. 55, 379-400], We determined by analytical ultracentrifugation the dimer-tetramer equilibrium constant of five single and three double mutants of human Kb, One mutation is at the stationary alpha(1) beta(1) interface, and all of the others are at the sliding alpha(1) beta(2) interface where cleavage of the tetramer into dimers and ligand-linked allosteric changes are known to occur. A surprisingly good linear correlation between the change in the free energy of association of the mutants and the change in buried hydrophobic surface area was obtained, after corrections for the energetic cost of losing steric complementarity at the ap dimer interface, The slope yields an interface stabilization free energy of -15 +/- 1.2 cal/mol upon burial of 1 Angstrom(2) of hydrophobic surface, in very good agreement with the theoretical estimate given by Eisenberg and McLachlan [Eisenberg, D. & McLachlan, A. D. (1986) Nature (London) 319, 199-203].
allosteric regulation; hemoglobin; site directed mutagenesis; thermodynamics
01 Pubblicazione su rivista::01a Articolo in rivista
Free energy of burying hydrophobic residues in the interface between protein subunits / Vallone, Beatrice; Miele, Adriana Erica; P., Vecchini; Chiancone, Emilia; Brunori, Maurizio. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 0027-8424. - STAMPA. - 95:11(1998), pp. 6103-6107. [10.1073/pnas.95.11.6103]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/241762
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