1K9P: Crystal Structure Of Calcium Free (or Apo) Human S100a6

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.
PDB ID: 1K9PDownload
MMDB ID: 19266
PDB Deposition Date: 2001/10/29
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 1K9P: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 1K9P
Label Count Molecule
Proteins (2 molecules)
S100a6(Gene symbol: S100A6)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB