Experimental Data Snapshot

  • Resolution: 1.76 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.185 

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This is version 1.3 of the entry. See complete history


Crystal structures of S100A6 in the Ca(2+)-free and Ca(2+)-bound states: the calcium sensor mechanism of S100 proteins revealed at atomic resolution.

Otterbein, L.R.Kordowska, J.Witte-Hoffmann, C.Wang, C.L.Dominguez, R.

(2002) Structure 10: 557-567

  • DOI: https://doi.org/10.1016/s0969-2126(02)00740-2
  • Primary Citation of Related Structures:  
    1K8U, 1K96, 1K9K, 1K9P

  • PubMed Abstract: 

    S100A6 is a member of the S100 family of Ca(2+) binding proteins, which have come to play an important role in the diagnosis of cancer due to their overexpression in various tumor cells. We have determined the crystal structures of human S100A6 in the Ca(2+)-free and Ca(2+)-bound states to resolutions of 1.15 A and 1.44 A, respectively. Ca(2+) binding is responsible for a dramatic change in the global shape and charge distribution of the S100A6 dimer, leading to the exposure of two symmetrically positioned target binding sites. The results are consistent with S100A6, and most likely other S100 proteins, functioning as Ca(2+) sensors in a way analogous to the prototypical sensors calmodulin and troponin C. The structures have important implications for our understanding of target binding and cooperativity of Ca(2+) binding in the S100 family.

  • Organizational Affiliation

    Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
90Homo sapiensMutation(s): 0 
Gene Names: S100A6
UniProt & NIH Common Fund Data Resources
Find proteins for P06703 (Homo sapiens)
Explore P06703 
Go to UniProtKB:  P06703
PHAROS:  P06703
GTEx:  ENSG00000197956 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP06703
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.76 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.185 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.61α = 90
b = 58.439β = 90
c = 51.03γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-04-10
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-16
    Changes: Data collection, Database references, Derived calculations, Refinement description