231L | pdb_0000231l

Deposited: 1997-10-03 Released: 1998-01-14
Deposition Author(s): Lipscomb, L.A., Drew, D.L., Gassner, N., Baase, W.A., Matthews, B.W.

Experimental Data Snapshot

wwPDB Validation 3D Report Full Report

This is version 1.4 of the entry. See complete history.

(1998) Protein Sci 7: 765-773

PubMed Abstract:
The substitution of methionines with leucines within the interior of a protein is expected to increase stability both because of a more favorable solvent transfer term as well as the reduced entropic cost of holding a leucine side chain in a defined position. Together, these two terms are expected to contribute about 1.4 kcal/mol to protein stability for each Met --> Leu substitution when fully buried. At the same time, this expected beneficial effect may be offset by steric factors due to differences in the shape of leucine and methionine. To investigate the interplay between these factors, all methionines in T4 lysozyme except at the amino-terminus were individually replaced with leucine. Of these mutants, M106L and M120L have stabilities 0.5 kcal/mol higher than wild-type T4 lysozyme, while M6L is significantly destabilized (-2.8 kcal/mol). M102L, described previously, is also destabilized (-0.9 kcal/mol). Based on this limited sample it appears that methionine-to-leucine substitutions can increase protein stability but only in a situation where the methionine side chain is fully or partially buried, yet allows the introduction of the leucine without concomitant steric interference. The variants, together with methionine-to-lysine substitutions at the same sites, follow the general pattern that substitutions at rigid, internal sites tend to be most destabilizing, whereas replacements at more solvent-exposed sites are better tolerated.

Organizational Affiliation

Institute of Molecular Biology, Howard Hughes Medical Institute and Department of Chemistry, University of Oregon, Eugene 97403, USA.

Macromolecule Content

Find similar proteins by:

| 3D Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
T4 LYSOZYME	A	164	Tequatrovirus T4	Mutation(s): 3 Gene Names: T4 LYSOZYME EC: 3.2.1.17
UniProt
Find proteins for P00720 (Enterobacteria phage T4) Explore P00720 Go to UniProtKB: P00720
Entity Groups
Sequence Clusters	30% Identity 50% Identity 70% Identity 90% Identity 95% Identity 100% Identity
UniProt Group	P00720
Sequence Annotations Expand
Reference Sequence

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram	3D Interactions
CL Query on CL Download:Ideal Coordinates CCD File SDF format, chain B [auth A] MOL2 format, chain B [auth A] mmCIF format, chain B [auth A]	B [auth A]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M		Interactions Focus chain B [auth A] Interactions & Density Focus chain B [auth A]