2C8K

Crystal Structure of (SR) Calcium-ATPase E2(Tg) with partially occupied AMPPCP site

Summary for 2C8K

• Entry DOI: 10.2210/pdb2c8k/pdb
• Related: 1FQU 1IWO 1KJU 1SU4 1T5S 1T5T 1VFP 1WPE 1WPG 1XP5 2AGV 2BY4 2C88 2C8L
• Descriptor: ARCOPLASMIC/ENDOPLASMIC RETICULUM CALCIUM ATPASE 1, OCTANOIC ACID [3S-[3ALPHA, 3ABETA, 4ALPHA, 6BETA, 6ABETA, 7BETA, 8ALPHA(Z), 9BALPHA]]-6-(ACETYLOXY)-2,3,-3A,4,5,6,6A,7,8,9B-DECAHYDRO-3,3A-DIHYDROXY-3,6,9-TRIMETHYL-8-[(2-METHYL-1-OXO-2-BUTENYL)OX Y]-2-OXO-4-(1-OXOBUTOXY)-AZULENO[4,5-B]FURAN-7-YL ESTER, PHOSPHOMETHYLPHOSPHONIC ACID ADENYLATE ESTER, ... (5 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: 1
• Total formula weight: 110805.83

Authors

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

Primary citation

Jensen, A.M.,Sorensen, T.L.,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 (2.8 Å)