2c8l

File:2c8l.gif

spinqualitylabelsall models 2c8l, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF (SR) CALCIUM-ATPASE E2(TG) FORM

OverviewOverview

We present crystal structures of the calcium-free E2 state of the, sarcoplasmic reticulum Ca2+ -ATPase, stabilized by the inhibitor, thapsigargin and the ATP analog AMPPCP. The structures allow us to, describe the ATP binding site in a modulatory mode uncoupled from the, Asp351 phosphorylation site. The Glu439 side chain interacts with AMPPCP, via an Mg2+ ion in accordance with previous Fe2+ -cleavage studies, implicating this residue in the ATPase cycle and in magnesium binding., Functional data on Ca2+ mediated activation indicate that the crystallized, state represents an initial stage of ATP modulated deprotonation of E2, preceding the binding of Ca2+ ions in the membrane from the cytoplasmic, side. We propose a mechanism of Ca2+ activation of phosphorylation leading, directly from the compact E2-ATP form to the Ca2E1-ATP state. In addition, a role of Glu439 in ATP modulation of other steps of the functional cycle, is suggested.

About this StructureAbout this Structure

2C8L is a Single protein structure of sequence from Oryctolagus cuniculus with NA and TG1 as ligands. Active as Calcium-transporting ATPase, with EC number 3.6.3.8 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

ReferenceReference

Modulatory and catalytic modes of ATP binding by the calcium pump., Jensen AM, Sorensen TL, Olesen C, Moller JV, Nissen P, EMBO J. 2006 Jun 7;25(11):2305-14. Epub 2006 May 18. PMID:16710301

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