2fh2
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| , resolution 2.500Å | |||||||
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| Coordinates: | save as pdb, mmCIF, xml | ||||||
C-terminal half of gelsolin soaked in EGTA at pH 4.5
OverviewOverview
Gelsolin is a calcium and pH-sensitive modulator of actin filament length. Here, we use X-ray crystallography to examine the extraction and exchange of calcium ions from their binding sites in different crystalline forms of the activated N and C-terminal halves of gelsolin, G1-G3 and G4-G6, respectively. We demonstrate that the combination of calcium and low pH activating conditions do not induce conformational changes in G4-G6 beyond those elicited by calcium alone. EGTA is able to remove calcium ions bound to the type I and type II metal ion-binding sites in G4-G6. Constrained by crystal contacts and stabilized by interdomain interaction surfaces, the gross structure of calcium-depleted G4-G6 remains that of the activated form. However, high-resolution details of changes in the ion-binding sites may represent the initial steps toward restoration of the arrangement of domains found in the calcium-free inactive form of gelsolin in solution. Furthermore, bathing crystals with the trivalent calcium ion mimic, Tb3+, results in anomalous scattering data that permit unequivocal localization of terbium ions in each of the proposed type I and type II ion-binding sites of both halves of gelsolin. In contrast to predictions based on solution studies, we find that no calcium ion is immune to exchange.
DiseaseDisease
Known disease associated with this structure: Amyloidosis, Finnish type OMIM:[137350]
About this StructureAbout this Structure
2FH2 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Calcium ion exchange in crystalline gelsolin., Chumnarnsilpa S, Loonchanta A, Xue B, Choe H, Urosev D, Wang H, Lindberg U, Burtnick LD, Robinson RC, J Mol Biol. 2006 Mar 31;357(3):773-82. Epub 2006 Jan 26. PMID:16466744
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