In general, alpha-helical conformations in proteins depend in large part on the amino acid residues within the helix and their proximal interactions. For example, an alanine residue has a high propensity to adopt an alpha-helical conformation, whereas that of a glycine residue is low. The sequence preferences for beta-sheet formation are less obvious. To identify the factors that influence beta-sheet conformation, a series of scanning polyalanine mutations were made within the strands and associated turns of the beta-sheet region in T4 lysozyme. For each construct the stability of the folded protein was reduced substantially, consistent with removal of native packing interactions. However, the crystal structures showed that each of the mutants retained the beta-sheet conformation. These results suggest that the structure of the beta-sheet region of T4 lysozyme is maintained to a substantial extent by tertiary interactions with the surrounding parts of the protein. Such tertiary interactions may be important in determining the structures of beta-sheets in general. Study holds ProTherm entries: 17222, 17223, 17224, 17225, 17226, 17227, 17228, 17229, 17230, 17231, 17232, 17233, 17234 Extra Details: 1 mM EDTA was added in the experiment. Pseudo wild type, C54T, C97A. beta-sheet; T4 lysozyme; secondary structure; tertiary interactions; alanine mutagenesis
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:49 p.m.
|Number of data points||39|
|Proteins||Endolysin ; Endolysin|
|Assays/Quantities/Protocols||Experimental Assay: dCp pH:3.05, temp:51.6 C ; Experimental Assay: ddG pH:3.05 ; Experimental Assay: dCp temp:51.6 C, pH:3.02 ; Experimental Assay: ddG pH:3.02 ; Experimental Assay: dCp pH:3.05 ; Experimental Assay: Tm pH:3.05 ; Experimental Assay: dHvH pH:3.05 ; Experimental Assay: dCp pH:3.02 ; Experimental Assay: Tm pH:3.02 ; Experimental Assay: dHvH pH:3.02 ; Derived Quantity: dTm pH:3.05 ; Derived Quantity: dTm pH:3.02|
|Libraries||Mutations for sequence MNIFEMLRIDEGLRLKIYKDTEGYYTIGIGHLLTKSPSLNAAKSELDKAIGRNCNGVITKDEAEKLFNQDVDAAVRGILRNAKLKPVYDSLDAVRRCALINMVFQMGETGVAGFTNSLRMLQQKRWDEAAVNLAKSRWYNQTPNRAKRVITTFRTGTWDAYKNL|