7bt2

Publication Abstract from PubMed

Under physiological conditions, most Ca(2+)-ATPase (SERCA) molecules bind ATP before binding the Ca(2+) transported. SERCA has a high affinity for ATP even in the absence of Ca(2+), and ATP accelerates Ca(2+) binding at pH values lower than 7, where SERCA is in the E2 state with low-affinity Ca(2+)-binding sites. Here we describe the crystal structure of SERCA2a, the isoform predominant in cardiac muscle, in the E2.ATP state at 3.0-A resolution. In the crystal structure, the arrangement of the cytoplasmic domains is distinctly different from that in canonical E2. The A-domain now takes an E1 position, and the N-domain occupies exactly the same position as that in the E1.ATP.2Ca(2+) state relative to the P-domain. As a result, ATP is properly delivered to the phosphorylation site. Yet phosphoryl transfer never takes place without the filling of the two transmembrane Ca(2+)-binding sites. The present crystal structure explains what ATP binding itself does to SERCA and how nonproductive phosphorylation is prevented in E2.

What ATP binding does to the Ca(2+) pump and how nonproductive phosphoryl transfer is prevented in the absence of Ca(2).,Kabashima Y, Ogawa H, Nakajima R, Toyoshima C Proc Natl Acad Sci U S A. 2020 Jul 16. pii: 2006027117. doi:, 10.1073/pnas.2006027117. PMID:32675243^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.