Residues in beta-sheets occur in two distinct tertiary contexts: central strands, bordered on both sides by other beta-strands, and edge strands, bordered on only a single side by another beta-strand. The delta delta G values for beta-sheet formation measured at an edge beta-strand of the IgG-binding domain of protein G(GB1) are quite different from those obtained previously at a central position in the same protein. In particular, there is no correlation at the edge position with statistically determined beta-sheet-forming preferences. The differences between beta-sheet propensities measured at central and edge beta-strands, delta delta delta G values, correlate with the values of water/octanol transfer free energies and side-chain non-polar surface area for the amino acids. These results strongly suggest that, unlike alpha-helix formation, beta-sheet formation is determined in large part by tertiary context, even at solvent-accessible sites, and not by intrinsic secondary structure preferences.
Submitter: Connie Wang
Submission Date: Nov. 7, 2017, 9:31 p.m.
|Number of data points||58|
|Proteins||Immunoglobulin G-binding protein G|
|Assays/Quantities/Protocols||Experimental Assay: Ka/KaAAA-44Thr -- Relative binding constant to human Fc AAA-44Thr ; Experimental Assay: ∆∆G (relative to alanine) ; Experimental Assay: Tm|
|Libraries||Parameters of beta-sheet formation|