3SWL

Crystal Structure Analysis of H74A Mutant of Human CLIC1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.338 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.247 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Role of individual histidines in the pH-dependent global stability of human chloride intracellular channel 1.

Achilonu, I.Fanucchi, S.Cross, M.Fernandes, M.Dirr, H.W.

(2012) Biochemistry 51: 995-1004

  • DOI: https://doi.org/10.1021/bi201541w
  • Primary Citation of Related Structures:  
    3P90, 3QR6, 3SWL

  • PubMed Abstract: 

    Chloride intracellular channel proteins exist in both a soluble cytosolic form and a membrane-bound form. The mechanism of conversion between the two forms is not properly understood, although one of the contributing factors is believed to be the variation in pH between the cytosol (~7.4) and the membrane (~5.5). We systematically mutated each of the three histidine residues in CLIC1 to an alanine at position 74 and a phenylalanine at positions 185 and 207. We examined the effect of the histidine-mediated pH dependence on the structure and global stability of CLIC1. None of the mutations were found to alter the global structure of the protein. However, the stability of H74A-CLIC1 and H185F-CLIC1, as calculated from the equilibrium unfolding data, is no longer dependent on pH because similar trends are observed at pH 7.0 and 5.5. The crystal structures show that the mutations result in changes in the local hydrogen bond coordination. Because the mutant total free energy change upon unfolding is not different from that of the wild type at pH 7.0, despite the presence of intermediates that are not seen in the wild type, we propose that it may be the stability of the intermediate state rather than the native state that is dependent on pH. On the basis of the lower stability of the intermediate in the H74A and H185F mutants compared to that of the wild type, we conclude that both His74 and His185 are involved in triggering the pH changes to the conformational stability of wild-type CLIC1 via their protonation, which stabilizes the intermediate state.


  • Organizational Affiliation

    Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chloride intracellular channel protein 1236Homo sapiensMutation(s): 1 
Gene Names: CLIC1G6NCC27
UniProt & NIH Common Fund Data Resources
Find proteins for O00299 (Homo sapiens)
Explore O00299 
Go to UniProtKB:  O00299
PHAROS:  O00299
GTEx:  ENSG00000213719 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO00299
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.338 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.247 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.199α = 90
b = 41.542β = 90
c = 66.705γ = 90
Software Package:
Software NamePurpose
SAINTdata scaling
SAINTdata reduction
PHASERphasing
DMphasing
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-08-24
    Type: Initial release
  • Version 1.1: 2012-05-23
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references