Database accession: MF7000580
Name: Calcyclin
PDB ID: 1cnp
Experimental method: NMR
Assembly: Homodimer
Source organism: Oryctolagus cuniculus
Primary publication of the structure:
Potts BC, Smith J, Akke M, Macke TJ, Okazaki K, Hidaka H, Case DA, Chazin WJ
The structure of calcyclin reveals a novel homodimeric fold for S100 Ca(2+)-binding proteins.
(1995) Nat. Struct. Biol. 2: 790-6
PMID: 7552751
Abstract:
The S100 calcium-binding proteins are implicated as effectors in calcium-mediated signal transduction pathways. The three-dimensional structure of the S100 protein calcyclin has been determined in solution in the apo state by NMR spectroscopy and a computational strategy that incorporates a systematic docking protocol. This structure reveals a symmetric homodimeric fold that is unique among calcium-binding proteins. Dimerization is mediated by hydrophobic contacts from several highly conserved residues, which suggests that the dimer fold identified for calcyclin will serve as a structural paradigm for the S100 subfamily of calcium-binding proteins.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
calcium ion binding calcium ion binding
calcium-dependent protein binding calcium-dependent protein binding
S100 protein binding S100 protein binding
Biological process: not assigned
Cellular component:
collagen-containing extracellular matrix collagen-containing extracellular matrix
cytoplasmic side of plasma membrane cytoplasmic side of plasma membrane
cytosol cytosol
extracellular space extracellular space
nuclear envelope nuclear envelope
perinuclear region of cytoplasm perinuclear region of cytoplasm
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, B
Notes: All chains according to the most probable oligomerization state stored in PDBe were considered.
Number of unique protein segments: 1
Name: Protein S100-A6
Source organism: Oryctolagus cuniculus
Length: 90 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMASPLDQAIGLLIGIFHKYSGKEGDKHTLSKKELKELIQKELTIGSKLQDAEIVKLMDDLDRNKDQEVNFQEYITFLGALAMIYNEALKG
UniProtKB AC: P30801 (positions: 1-90)
Coverage: 100%
Name: Protein S100-A6
Source organism: Oryctolagus cuniculus
Length: 90 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMASPLDQAIGLLIGIFHKYSGKEGDKHTLSKKELKELIQKELTIGSKLQDAEIVKLMDDLDRNKDQEVNFQEYITFLGALAMIYNEALKG
UniProtKB AC: P30801 (positions: 1-90)
Coverage: 100%
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Representative domain in related structures: S-100/ICaBP type EF hand dimer
Evidence level: Direct evidence
Evidence coverage: The full structure participates in mutual synergistic folding.
Complex Evidence:
GuHCl-induced denaturation of the S100B protein dimer showed that it follows a two-state unfolding/refolding process (PMID:11888280). Other S100 proteins also showed two-state unfolding, no folded monomers were observed (PMID:18346834, PMID:18706914). The dimer has a globular and compact structure with the four helices in each subunit aligning to form a unicornate-type four-helix bundle (PMID:11790100). The hydrophobic core extends through the dimer interface.
Chain A:
N/A
Chain B:
N/A
Surface and contacts features:
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). Download the CIF file (.cif)
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