Protein stability and electrostatic interactions between solvent exposed charged side chains |
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Authors: | M Akke S Forsén |
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Affiliation: | Physical Chemistry 2, Lund University, Sweden. |
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Abstract: | To investigate the contribution to protein stability of electrostatic interactions between charged surface residues, we have studied the effect of substituting three negatively charged solvent exposed residues with their side-chain amide analogs in bovine calbindin D9k--a small (Mr 8,500) globular protein of the calmodulin superfamily. The free energy of urea-induced unfolding for the wild-type and seven mutant proteins has been measured. The mutant proteins have increased stability towards unfolding relative to the wild-type. The experimental results correlate reasonably well with theoretically calculated relative free energies of unfolding and show that electrostatic interactions between charges on the surface of a protein can have significant effects on protein stability. |
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Keywords: | urea induced unfolding increased stability site-directed mutagenesis calbindin D9k |
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