5A3Q: Crystal structure of the (SR) Calcium ATPase E2-vanadate complex bound to thapsigargin and TNP-AMPPCP

Citation:
Abstract
Vanadate 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.
PDB ID: 5A3QDownload
MMDB ID: 138319
PDB Deposition Date: 2015/6/2
Updated in MMDB: 2016/04
Experimental Method:
x-ray diffraction
Resolution: 3.05  Å
Source Organism:
Similar Structures:
Biological Unit for 5A3Q: monomeric; determined by author and by software (PISA)

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