1uwo
From Proteopedia
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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. Known structural/functional Sites: , , and . 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 Tue Dec 18 18:14:55 2007
