3BA6: Structure Of The Ca2e1p Phosphoenzyme Intermediate Of The Serca Ca2+- Atpase

Citation:
Abstract
The sarcoplasmic reticulum Ca2+-ATPase, a P-type ATPase, has a critical role in muscle function and metabolism. Here we present functional studies and three new crystal structures of the rabbit skeletal muscle Ca2+-ATPase, representing the phosphoenzyme intermediates associated with Ca2+ binding, Ca2+ translocation and dephosphorylation, that are based on complexes with a functional ATP analogue, beryllium fluoride and aluminium fluoride, respectively. The structures complete the cycle of nucleotide binding and cation transport of Ca2+-ATPase. Phosphorylation of the enzyme triggers the onset of a conformational change that leads to the opening of a luminal exit pathway defined by the transmembrane segments M1 through M6, which represent the canonical membrane domain of P-type pumps. Ca2+ release is promoted by translocation of the M4 helix, exposing Glu 309, Glu 771 and Asn 796 to the lumen. The mechanism explains how P-type ATPases are able to form the steep electrochemical gradients required for key functions in eukaryotic cells.
PDB ID: 3BA6Download
MMDB ID: 61432
PDB Deposition Date: 2007/11/7
Updated in MMDB: 2007/12
Experimental Method:
x-ray diffraction
Resolution: 2.8  Å
Source Organism:
Similar Structures:
Biological Unit for 3BA6: monomeric; determined by author and by software (PISA)
Molecular Components in 3BA6
Label Count Molecule
Protein (1 molecule)
1
Sarcoplasmic/endoplasmic Reticulum Calcium Atpase 1(Gene symbol: ATP2A1)
Molecule annotation
Chemicals (5 molecules)
1
3
2
1
3
1
* Click molecule labels to explore molecular sequence information.

Citing MMDB
.