1cfp
From Proteopedia
S100B (S100BETA) NMR DATA WAS COLLECTED FROM A SAMPLE OF CALCIUM FREE PROTEIN AT PH 6.3 AND A TEMPERATURE OF 311 K AND 1.7-6.9 MM CONCENTRATION, 25 STRUCTURES
Structural highlights
FunctionS100B_BOVIN Weakly binds calcium but binds zinc very tightly-distinct binding sites with different affinities exist for both ions on each monomer. Physiological concentrations of potassium ion antagonize the binding of both divalent cations, especially affecting high-affinity calcium-binding sites. Binds to and initiates the activation of STK38 by releasing autoinhibitory intramolecular interactions within the kinase. Interaction with AGER after myocardial infarction may play a role in myocyte apoptosis by activating ERK1/2 and p53/TP53 signaling. Could assist ATAD3A cytoplasmic processing, preventing aggregation and favoring mitochondrial localization (By similarity).[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBACKGROUND. S100B (S100beta) is a member of the S100 family of small calcium-binding proteins: members of this family contain two helix-loop-helix calcium-binding motifs and interact with a wide range of proteins involved mainly in the cytoskeleton and cell proliferation. S100B is a neurite-extension factor and levels of S100B are elevated in the brains of patients with Alzheimer's disease or Down's syndrome: the pattern of S100B overexpression in Alzheimer's disease correlates with the pattern of neuritic-plaque formation. Identification of a growing class of S100 proteins and the likely neurochemical importance of S100B make the determination of the structure of S100B of interest. RESULTS. We have used NMR to determine the structure of the reduced S100B homodimer in the absence of calcium. Each monomer consists of a four-helix bundle, arranged in the dimer in an antiparallel fashion. The fourth helix of each monomer runs close to the equivalent helix of the other monomer for almost its full length, extending the hydrophobic core through the interface. The N-terminal, but not the C-terminal, calcium-binding loop is similar to the equivalent loop in the monomeric S100 protein calbindin and is in a conformation ready to bind calcium. CONCLUSIONS. The novel dimer structure reported previously for calcyclin (S100A6) is the common fold for the dimeric S100B proteins. Calcium binding to the C-terminal calcium-binding loop would be expected to require a conformational change, which might provide a signal for activation. The structure suggests regions of the molecule likely to be involved in interactions with effector molecules. The solution structure of the bovine S100B protein dimer in the calcium-free state.,Kilby PM, Van Eldik LJ, Roberts GC Structure. 1996 Sep 15;4(9):1041-52. PMID:8805590[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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