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Crystal Structure of the E2 magnesium fluoride complex of the (SR) Ca2+-ATPase with bound CPA and AMPPCPCrystal Structure of the E2 magnesium fluoride complex of the (SR) Ca2+-ATPase with bound CPA and AMPPCP
Structural highlights
FunctionAT2A1_RABIT This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen. Contributes to calcium sequestration involved in muscular excitation/contraction (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe have determined the structure of the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) in an E2.P(i)-like form stabilized as a complex with MgF(4)(2-), an ATP analog, adenosine 5'-(beta,gamma-methylene)triphosphate (AMPPCP), and cyclopiazonic acid (CPA). The structure determined at 2.5A resolution leads to a significantly revised model of CPA binding when compared with earlier reports. It shows that a divalent metal ion is required for CPA binding through coordination of the tetramic acid moiety at a characteristic kink of the M1 helix found in all P-type ATPase structures, which is expected to be part of the cytoplasmic cation access pathway. Our model is consistent with the biochemical data on CPA function and provides new measures in structure-based drug design targeting Ca(2+)-ATPases, e.g. from pathogens. We also present an extended structural basis of ATP modulation pinpointing key residues at or near the ATP binding site. A structural comparison to the Na(+),K(+)-ATPase reveals that the Phe(93) side chain occupies the equivalent binding pocket of the CPA site in SERCA, suggesting an important role of this residue in stabilization of the potassium-occluded E2 state of Na(+),K(+)-ATPase. Cyclopiazonic acid is complexed to a divalent metal ion when bound to the sarcoplasmic reticulum Ca2+-ATPase.,Laursen M, Bublitz M, Moncoq K, Olesen C, Moller JV, Young HS, Nissen P, Morth JP J Biol Chem. 2009 May 15;284(20):13513-8. Epub 2009 Mar 16. PMID:19289472[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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