Transport mechanism of the sarcoplasmic reticulum Ca2+ -ATPase pump.
The sarcoplasmic reticulum Ca(2+)-ATPase (SERCA1a) belongs to the group of P-type ATPases, which actively transport inorganic cations across membranes at the expense of ATP hydrolysis. Three-dimensional structures of several transport intermediates of SERCA1a, stabilized by structural analogues of ATP and phosphoryl groups, are now available at atomic resolution. This has enabled the transport cycle of the protein to be described, including the coupling of Ca(2+) occlusion and phosphorylation by ATP, and of proton counter-transport and dephosphorylation. From these structures, Ca(2+)-ATPase gradually emerges as a molecular mechanical device in which some of the transmembrane segments perform Ca(2+) transport by piston-like movements and by the transmission of reciprocating movements that affect the chemical reactivity of the cytosolic globular domains.
Møller
Jesper V
JV
Department of Biophysics, Institute of Physiology and Biophysics, University of Aarhus, Ole Worms Allé 185, DK-8000 Aarhus C, Denmark.
Nissen
Poul
P
Sørensen
Thomas L-M
TL
le Maire
Marc
M
D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000737:chemistry* / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D010766:Phosphorylation; D011487:Protein Conformation; D011522:Protons; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D013816:Thermodynamics
D007527:Isoenzymes; D011522:Protons; D000255:Adenosine Triphosphate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium