3N5K

Structure Of The (Sr)Ca2+-ATPase E2-AlF4- Form

Summary for 3N5K

• Entry DOI: 10.2210/pdb3n5k/pdb
• Related: 1XP5 3B9R
• Descriptor: Sarcoplasmic/endoplasmic reticulum calcium ATPase 1, 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, MAGNESIUM ION, ... (7 entities in total)
• Functional Keywords: serca, adenosine triphosphate, calcium-transporting atpases, thapsigargin, hydrolase
• Biological source: Oryctolagus cuniculus (European rabbit,Japanese white rabbit,domestic rabbit,rabbits)
• Cellular location: Endoplasmic reticulum membrane; Multi-pass membrane protein: P04191
• Total number of polymer chains: 2
• Total formula weight: 221075.60

Authors

Bublitz, M.,Olesen, C.,Poulsen, H.,Morth, J.P.,Moller, J.V.,Nissen, P. (deposition date: 2010-05-25, release date: 2011-06-08, Last modification date: 2024-11-06)

Primary citation

Bublitz, M.,Musgaard, M.,Poulsen, H.,Thogersen, L.,Olesen, C.,Schiott, B.,Morth, J.P.,Moller, J.V.,Nissen, P.
Ion pathways in the sarcoplasmic reticulum Ca2+-ATPase.
J.Biol.Chem., 288:10759-10765, 2013

PubMed Abstract: The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) is a transmembrane ion transporter belonging to the P(II)-type ATPase family. It performs the vital task of re-sequestering cytoplasmic Ca(2+) to the sarco/endoplasmic reticulum store, thereby also terminating Ca(2+)-induced signaling such as in muscle contraction. This minireview focuses on the transport pathways of Ca(2+) and H(+) ions across the lipid bilayer through SERCA. The ion-binding sites of SERCA are accessible from either the cytoplasm or the sarco/endoplasmic reticulum lumen, and the Ca(2+) entry and exit channels are both formed mainly by rearrangements of four N-terminal transmembrane α-helices. Recent improvements in the resolution of the crystal structures of rabbit SERCA1a have revealed a hydrated pathway in the C-terminal transmembrane region leading from the ion-binding sites to the cytosol. A comparison of different SERCA conformations reveals that this C-terminal pathway is exclusive to Ca(2+)-free E2 states, suggesting that it may play a functional role in proton release from the ion-binding sites. This is in agreement with molecular dynamics simulations and mutational studies and is in striking analogy to a similar pathway recently described for the related sodium pump. We therefore suggest a model for the ion exchange mechanism in P(II)-ATPases including not one, but two cytoplasmic pathways working in concert.

PubMed: 23400778
DOI: 10.1074/jbc.R112.436550

Experimental method

X-RAY DIFFRACTION (2.2 Å)