1LYI

DISSECTION OF HELIX CAPPING IN T4 LYSOZYME BY STRUCTURAL AND THERMODYNAMIC ANALYSIS OF SIX AMINO ACID SUBSTITUTIONS AT THR 59


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Observed: 0.153 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Dissection of helix capping in T4 lysozyme by structural and thermodynamic analysis of six amino acid substitutions at Thr 59.

Bell, J.A.Becktel, W.J.Sauer, U.Baase, W.A.Matthews, B.W.

(1992) Biochemistry 31: 3590-3596

  • DOI: https://doi.org/10.1021/bi00129a006
  • Primary Citation of Related Structures:  
    1LYE, 1LYF, 1LYG, 1LYH, 1LYI, 1LYJ

  • PubMed Abstract: 

    Threonine 59, a helix-capping residue at the amino terminus of the longest helix in T4 phage lysozyme, was substituted with valine, alanine, glycine, serine, asparagine, and aspartic acid. The valine, alanine, and glycine replacements were observed to be somewhat more destabilizing than serine, asparagine, and aspartic acid. The crystal structures of the different variants showed that changes in conformation occurred at the site of substitution, including Asp 61, which is nearby, as well as displacement of a solvent molecule that is hydrogen-bonded to the gamma-oxygen of Thr 59 in wild-type lysozyme. Neither the structures nor the stabilities of the mutant proteins support the hypothesis of Serrano and Fersht (1989) that glycine and alanine are better helix-capping residues than valine because a smaller-sized residue allows better hydration at the end of the helix. In the aspartic acid and asparagine replacements the substituted side chains form hydrogen bonds with the end of the helix, as does threonine and serine at this position. In contrast, however, the Asp and Asn side chains also make unusually close contacts with carbon atoms in Asp 61. This suggests a structural basis for the heretofore puzzling observations that asparagine is more frequently observed as a helix-capping residue than threonine [Richardson, J. S., & Richardson, D. C. (1988) Science 240, 1648-1652] yet Thr----Asn replacements at N-cap positions in barnase were found to be destabilizing [Serrano, L., & Fersht, A. R. (1989) Nature 342, 296-299].(ABSTRACT TRUNCATED AT 250 WORDS)


  • Organizational Affiliation

    Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene 97403.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
T4 LYSOZYME164Tequatrovirus T4Mutation(s): 0 
UniProt
Find proteins for P00720 (Enterobacteria phage T4)
Explore P00720 
Go to UniProtKB:  P00720
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00720
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Observed: 0.153 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.9α = 90
b = 60.9β = 90
c = 96.9γ = 120
Software Package:
Software NamePurpose
TNTrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other
  • Version 1.4: 2024-02-14
    Changes: Data collection, Database references, Derived calculations