3N8G

Structure of the (SR)Ca2+-ATPase Ca2-E1-CaAMPPCP form

Summary for 3N8G

• Entry DOI: 10.2210/pdb3n8g/pdb
• Related: 1T5S
• Descriptor: Sarcoplasmic/endoplasmic reticulum calcium ATPase 1 isoform SERCA 1a, CALCIUM ION, POTASSIUM ION, ... (5 entities in total)
• Functional Keywords: adenosine diphosphate, adenosine triphosphate, aluminum compounds, calcium-transporting atpases, crystallization, cytosol, fluorides, muscle fibers, fast-twitch, phosphorylation, protein conformation, sarcoplasmic reticulum calcium-transporting atpases, hydrolase
• Biological source: Oryctolagus cuniculus (European rabbit,Japanese white rabbit,domestic rabbit,rabbits)
• Total number of polymer chains: 1
• Total formula weight: 110267.12

Authors

Bublitz, M.,Olesen, C.,Poulsen, H.,Morth, J.P.,Moller, J.V.,Nissen, P. (deposition date: 2010-05-28, release date: 2011-06-08, Last modification date: 2023-09-06)

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 (2.585 Å)