1PWT

THERMODYNAMIC ANALYSIS OF ALPHA-SPECTRIN SH3 AND TWO OF ITS CIRCULAR PERMUTANTS WITH DIFFERENT LOOP LENGTHS: DISCERNING THE REASONS FOR RAPID FOLDING IN PROTEINS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.77 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.189 

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This is version 1.3 of the entry. See complete history


Literature

Thermodynamic analysis of alpha-spectrin SH3 and two of its circular permutants with different loop lengths: discerning the reasons for rapid folding in proteins.

Martinez, J.C.Viguera, A.R.Berisio, R.Wilmanns, M.Mateo, P.L.Filimonov, V.V.Serrano, L.

(1999) Biochemistry 38: 549-559

  • DOI: 10.1021/bi981515u
  • Primary Citation of Related Structures:  
    1PWT

  • PubMed Abstract: 
  • The temperature dependences of the unfolding-refolding reaction of a shorter version of the alpha-spectrin SH3 domain (PWT) used as a reference and of two circular permutants (with different poly-Gly loop lengths at the newly created fused loop) have been measured by differential scanning microcalorimetry and stopped-flow kinetics, to characterize the thermodynamic nature of the transition and native states ...

    The temperature dependences of the unfolding-refolding reaction of a shorter version of the alpha-spectrin SH3 domain (PWT) used as a reference and of two circular permutants (with different poly-Gly loop lengths at the newly created fused loop) have been measured by differential scanning microcalorimetry and stopped-flow kinetics, to characterize the thermodynamic nature of the transition and native states. Differential scanning calorimetry results show that all these species do not belong to the same temperature dependency of heat effect. The family of the N47-D48s circular permutant (with 0-6 Gly inserted at the fused-loop) shows a higher enthalpy as happens with the PWT domain. The wild type (WT) and the S19-P20s permutant family have a more similar behavior although the second is far less stable. The crystallographic structure of the PWT shows a hairpin formation in the region corresponding to the unstructured N-terminus tail of the WT, explaining the enthalpic difference. There is a very good correlation between the calorimetric changes and the structural differences between the WT, PWT, and two circular permutants that suggests that their unfolded state cannot be too different. Elongation of the fused loop in the two permutants, taking as a reference the protein with one inserted Gly, results in a small Gibbs energy change of entropic origin as theoretically expected. Eyring plots of the unfolding and refolding semireactions show different behaviors for PWT, S19-P20s, and N47-D48s in agreement with previous studies indicating that they have different transition states. The SH3 transition state is relatively close to the native state with regard to changes in heat capacity and entropy, indicating a high degree of compactness and order. Regarding the differences in thermodynamic parameters, it seems that rapid folding could be achieved in proteins by decreasing the entropic barrier.


    Organizational Affiliation

    EMBL, Heidelberg, Germany.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ALPHA SPECTRINA61Gallus gallusMutation(s): 0 
Gene Names: SPTAN1SPTA2
UniProt
Find proteins for P07751 (Gallus gallus)
Explore P07751 
Go to UniProtKB:  P07751
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.77 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.189 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 33α = 90
b = 42.4β = 90
c = 49.7γ = 90
Software Package:
Software NamePurpose
AMoREphasing
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-05-11
    Type: Initial release
  • Version 1.1: 2008-03-04
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-04-04
    Changes: Data collection