1uwo
From Proteopedia
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| Sites: | , , and | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CALCIUM FORM OF HUMAN S100B, NMR, 20 STRUCTURES
Overview
BACKGROUND: S100B is a homodimeric member of the EF-hand calcium-binding protein superfamily. The protein has been implicated in cellular processes such as cell differentiation and growth, plays a role in cytoskeletal structure and function, and may have a role in neuropathological diseases, such as Alzheimers. The effects of S100B are mediated via its interaction with target proteins. While several studies have suggested that this interaction is propagated through a calcium-induced conformational change, leading to the exposure of a hydrophobic region of S100B, the molecular details behind this structural alteration remain unclear. RESULTS: The solution structure of calcium-saturated human S100B (Ca(2+)-S100B) has been determined by heteronuclear NMR spectroscopy. Ca(2+)-S100B forms a well defined globular structure comprising four EF-hand calcium-binding sites and an extensive hydrophobic dimer interface. A comparison of Ca(2+)-S100B with apo S100B and Ca(2+)-calbindin D9k indicates that while calcium-binding to S100B results in little change in the site I EF-hand, it induces a backbone reorientation of the N terminus of the site II EF-hand. This reorientation leads to a dramatic change in the position of helix III relative to the other helices. CONCLUSIONS: The calcium-induced reorientation of calcium-binding site II results in the increased exposure of several hydrophobic residues in helix IV and the linker region. While following the general mechanism of calcium modulatory proteins, whereby a hydrophobic target site is exposed, the 'calcium switch' observed in S100B appears to be unique from that of other EF-hand proteins and may provide insights into target specificity among calcium modulatory proteins.
About this Structure
1UWO is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
A novel calcium-sensitive switch revealed by the structure of human S100B in the calcium-bound form., Smith SP, Shaw GS, Structure. 1998 Feb 15;6(2):211-22. PMID:9519411
Page seeded by OCA on Mon Mar 31 00:16:20 2008
