Replacements of Pro86 in phage T4 lysozyme extend an alpha-helix but do not alter protein stability.


Abstract

To investigate the relation between protein stability and the predicted stabilities of individual secondary structural elements, residue Pro86 in an alpha-helix in phage T4 lysozyme was replaced by ten different amino acids. The x-ray crystal structures of seven of the mutant lysozymes were determined at high resolution. In each case, replacement of the proline resulted in the formation of an extended alpha-helix. This involves a large conformational change in residues 81 to 83 and smaller shifts that extend 20 angstroms across the protein surface. Unexpectedly, all ten amino acid substitutions marginally reduce protein thermostability. This insensitivity of stability to the amino acid at position 86 is not simply explained by statistical and thermodynamic criteria for helical propensity. The observed conformational changes illustrate a general mechanism by which proteins can tolerate mutations. Study holds ProTherm entries: 1338, 1339, 1340, 1341, 1342, 1343, 1344, 1345, 1346, 1347, 1348, 1349, 1350, 1351, 1352, 1353, 1354, 1355, 1356 Extra Details: T4 lysozyme; alpha-helix; protein stability; crystal structure;,proline; conformational changes; thermodynamic

Submission Details

ID: uCYUqXvq

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:17 p.m.

Version: 1

Publication Details
Alber T;Bell JA;Sun DP;Nicholson H;Wozniak JA;Cook S;Matthews BW,Science (1988) Replacements of Pro86 in phage T4 lysozyme extend an alpha-helix but do not alter protein stability. PMID:3277275
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