2C9M

Structure of (SR) Calcium-ATPase in the Ca2E1 state solved in a P1 crystal form.

Summary for 2C9M

• Entry DOI: 10.2210/pdb2c9m/pdb
• Related: 1FQU 1IWO 1KJU 1SU4 1T5S 1T5T 1VFP 1WPE 1WPG 1XP5 2AGV 2BY4 2C88 2C8K 2C8L
• Descriptor: SARCOPLASMIC/ENDOPLASMIC RETICULUM CALCIUM ATPASE 1, CALCIUM ION, POTASSIUM ION, ... (4 entities in total)
• Functional Keywords: ca2+-atpase, p-type atpase, cation pump, membrane protein, modulatory atp, hydrolase, atp-binding, calcium transport, ion transport, metal-binding, nucleotide-binding, phosphorylation
• Biological source: ORYCTOLAGUS CUNICULUS (RABBIT)
• Cellular location: Endoplasmic reticulum membrane; Multi-pass membrane protein: P04191
• Total number of polymer chains: 2
• Total formula weight: 219634.80

Authors

Lund Jensen, A.-M.,Sorensen, T.L.-M.,Olesen, C.,Moller, J.V.,Nissen, P. (deposition date: 2005-12-13, release date: 2006-12-18, Last modification date: 2024-11-06)

Primary citation

Lund Jensen, A.-M.,Sorensen, T.L.-M.,Olesen, C.,Moller, J.V.,Nissen, P.
Modulatory and Catalytic Modes of ATP Binding by the Calcium Pump
Embo J., 25:2305-, 2006

PubMed Abstract: 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.

PubMed: 16710301
DOI: 10.1038/SJ.EMBOJ.7601135

Experimental method

X-RAY DIFFRACTION (3 Å)