1LZ4

ENTHALPIC DESTABILIZATION OF A MUTANT HUMAN LYSOZYME LACKING A DISULFIDE BRIDGE BETWEEN CYSTEINE-77 AND CYSTEINE-95


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Observed: 0.188 

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Literature

Enthalpic destabilization of a mutant human lysozyme lacking a disulfide bridge between cysteine-77 and cysteine-95.

Kuroki, R.Inaka, K.Taniyama, Y.Kidokoro, S.Matsushima, M.Kikuchi, M.Yutani, K.

(1992) Biochemistry 31: 8323-8328

  • DOI: 10.1021/bi00150a028
  • Primary Citation of Related Structures:  
    1LZ4

  • PubMed Abstract: 
  • To understand the role of disulfide bridges in protein stability, the thermodynamic changes in the denaturation of two mutant human lysozymes lacking a disulfide bridge between Cys-77 and Cys-95 (C77A and C77/95A) were analyzed using differential scanning calorimetry (DSC) ...

    To understand the role of disulfide bridges in protein stability, the thermodynamic changes in the denaturation of two mutant human lysozymes lacking a disulfide bridge between Cys-77 and Cys-95 (C77A and C77/95A) were analyzed using differential scanning calorimetry (DSC). At pH 3.0 and 57 degrees C, the stabilities of both the C77A and C77/95A mutants were decreased about 4.6 kcal.mol-1 in Gibbs free energy change. Under the same conditions, the enthalpy changes (delta H) were 94.8 and 90.8 kcal.mol-1, respectively, which were smaller than that of the wild type (100.8 kcal.mol-1). The destabilization of the mutants was caused by enthalpic factors. Although X-ray crystallography indicated that the mutants preserve the wild-type tertiary structure, removal of the disulfide bridge increased the flexibility of the native state of the mutants. This was indicated both by an increase in the crystallographic thermal factors (B-factors) and by a decrease in the affinity of N-acetylglucosamine trimer [(NAG)3] observed using isothermal titration calorimetry (DTC) due to entropic effects. Thus, the effect of cross-linking on the stability of a protein is not solely explained by the entropy change in denaturation.


    Related Citations: 
    • The Crystal Structure of a Mutant Human Lysozyme C77(Slash)95A with Increased Secretion Efficiency in Yeast
      Inaka, K., Taniyama, Y., Kikuchi, M., Morikawa, K., Matsushima, M.
      (1991) J Biol Chem 266: 12599

    Organizational Affiliation

    Protein Engineering Research Institute, Osaka, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
HUMAN LYSOZYME A130Homo sapiensMutation(s): 0 
Gene Names: LYZLZM
EC: 3.2.1.17
Find proteins for P61626 (Homo sapiens)
Explore P61626 
Go to UniProtKB:  P61626
NIH Common Fund Data Resources
PHAROS:  P61626
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Observed: 0.188 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.82α = 90
b = 60.86β = 90
c = 33.33γ = 90
Software Package:
Software NamePurpose
PROLSQrefinement

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