2C8L image
Deposition Date 2005-12-06
Release Date 2006-06-13
Last Version Date 2024-11-20
Entry Detail
PDB ID:
2C8L
Keywords:
Title:
Crystal Structure of (SR) Calcium-ATPase E2(Tg) form
Biological Source:
Source Organism:
Method Details:
Experimental Method:
Resolution:
3.10 Å
R-Value Free:
0.30
R-Value Work:
0.24
R-Value Observed:
0.24
Space Group:
P 41 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:SARCOPLASMIC/ENDOPLASMIC RETICULUM CALCIUM ATPASE 1
Gene (Uniprot):ATP2A1
Chain IDs:A
Chain Length:994
Number of Molecules:1
Biological Source:ORYCTOLAGUS CUNICULUS
Primary Citation
Modulatory and Catalytic Modes of ATP Binding by the Calcium Pump
Embo J. 25 2305 ? (2006)
PMID: 16710301 DOI: 10.1038/SJ.EMBOJ.7601135

Abstact

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.

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