2AGV

Crystal structure of the SR CA2+-ATPASE with BHQ and TG

Summary for 2AGV

• Entry DOI: 10.2210/pdb2agv/pdb
• Related: 1IWO 1SU4 1VFP 1WPE 1WPG
• Descriptor: Sarcoplasmic/endoplasmic reticulum calcium ATPase 1, SODIUM ION, OCTANOIC ACID [3S-[3ALPHA, 3ABETA, 4ALPHA, 6BETA, 6ABETA, 7BETA, 8ALPHA(Z), 9BALPHA]]-6-(ACETYLOXY)-2,3,-3A,4,5,6,6A,7,8,9B-DECAHYDRO-3,3A-DIHYDROXY-3,6,9-TRIMETHYL-8-[(2-METHYL-1-OXO-2-BUTENYL)OX Y]-2-OXO-4-(1-OXOBUTOXY)-AZULENO[4,5-B]FURAN-7-YL ESTER, ... (6 entities in total)
• Functional Keywords: membrane protein, p-type atpase, had fold, hydrolase, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Oryctolagus cuniculus (rabbit)
• Cellular location: Endoplasmic reticulum membrane; Multi-pass membrane protein: P04191
• Total number of polymer chains: 2
• Total formula weight: 225401.52

Authors

Toyoshima, C.,Obara, K.,Norimatsu, Y. (deposition date: 2005-07-27, release date: 2005-10-25, Last modification date: 2024-10-09)

Primary citation

Obara, K.,Miyashita, N.,Xu, C.,Toyoshima, I.,Sugita, Y.,Inesi, G.,Toyoshima, C.
Inaugural Article: Structural role of countertransport revealed in Ca2+ pump crystal structure in the absence of Ca2+.
Proc.Natl.Acad.Sci.USA, 102:14489-14496, 2005

PubMed Abstract: Ca(2+)-ATPase of sarcoplasmic reticulum is an ATP-powered Ca(2+) pump but also a H(+) pump in the opposite direction with no demonstrated functional role. Here, we report a 2.4-A-resolution crystal structure of the Ca(2+)-ATPase in the absence of Ca(2+) stabilized by two inhibitors, dibutyldihydroxybenzene, which bridges two transmembrane helices, and thapsigargin, also bound in the membrane region. Now visualized are water and several phospholipid molecules, one of which occupies a cleft between two transmembrane helices. Atomic models of the Ca(2+) binding sites with explicit hydrogens derived by continuum electrostatic calculations show how water and protons fill the space and compensate charge imbalance created by Ca(2+)-release. They suggest that H(+) countertransport is a consequence of a requirement for maintaining structural integrity of the empty Ca(2+)-binding sites. For this reason, cation countertransport is probably mandatory for all P-type ATPases and possibly accompanies transport of water as well.

PubMed: 16150713
DOI: 10.1073/pnas.0506222102

Experimental method

X-RAY DIFFRACTION (2.4 Å)