Measurement of the beta-sheet-forming propensities of amino acids


Abstract

Several model systems have been used to evaluate the alpha-helical propensities of different amino acids. In contrast, experimental quantitation of beta-sheet preferences has been addressed in only one model system, a zinc-finger peptide. Here we measure the relative propensity for beta-sheet formation of the twenty naturally occurring amino acids in a variant of the small, monomeric, beta-sheet-rich, IgG-binding domain from protein G. Amino-acid substitutions were made at a guest site on the solvent-exposed surface of the beta-sheet. Several criteria were used to establish that the mutations did not cause significant structural changes: binding to the Fc domain of IgG, calorimetric unfolding and NMR spectroscopy. Characterization of the terminal stabilities of these proteins leads to a thermodynamic scale for beta-sheet propensities that spans a range of approximately 2 kcal mol-1 for the naturally occurring amino acids, excluding proline. The magnitude of the differences suggests that beta-sheet preferences can be important determinants of protein stability.

Submission Details

ID: eqrHpUST3

Submitter: Marie Ary

Submission Date: Feb. 23, 2017, 12:12 p.m.

Version: 1

Publication Details
Minor DL Jr;Kim PS,Nature (1994) Measurement of the beta-sheet-forming propensities of amino acids. PMID:8107853
Additional Information

Sequence Assay Result Units