5a3r
From Proteopedia
Crystal structure of the (SR) Calcium ATPase E2.BeF3- complex bound to TNP-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). Publication Abstract from PubMedVanadate is the hallmark inhibitor of the P-type ATPase family; however, structural details of its inhibitory mechanism have remained unresolved. We have determined the crystal structure of sarcoplasmic reticulum Ca(2+)-ATPase with bound vanadate in the absence of Ca(2+). Vanadate is bound at the catalytic site as a planar VO3(-) in complex with water and Mg(2+) in a dephosphorylation transition-state-like conformation. Validating bound VO3(-) by anomalous difference Fourier maps using long-wavelength data we also identify a hitherto undescribed Cl(-) site near the dephosphorylation site. Crystallization was facilitated by trinitrophenyl (TNP)-derivatized nucleotides that bind with the TNP moiety occupying the binding pocket that normally accommodates the adenine of ATP, rationalizing their remarkably high affinity for E2P-like conformations of the Ca(2+)-ATPase. A comparison of the configurations of bound nucleotide analogs in the E2.VO3(-) structure with that in E2.BeF3(-) (E2P ground state analog) reveals multiple binding modes to the Ca(2+)-ATPase. Crystal Structure of the Vanadate-Inhibited Ca(2+)-ATPase.,Clausen JD, Bublitz M, Arnou B, Olesen C, Andersen JP, Moller JV, Nissen P Structure. 2016 Apr 5;24(4):617-23. doi: 10.1016/j.str.2016.02.018. PMID:27050689[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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