1vfp
From Proteopedia
Crystal structure of the SR CA2+-ATPase with bound AMPPCP
Overview
P-type ATPases are ATP-powered ion pumps that establish ion concentration gradients across cell and organelle membranes. Here, we describe the crystal structure of the Ca2+ pump of skeletal muscle sarcoplasmic reticulum, a representative member of the P-type ATPase superfamily, with an ATP analogue, a Mg2+ and two Ca2+ ions in the respective binding sites. In this state, the ATP analogue reorganizes the three cytoplasmic domains (A, N and P), which are widely separated without nucleotide, by directly bridging the N and P domains. The structure of the P-domain itself is altered by the binding of the ATP analogue and Mg2+. As a result, the A-domain is tilted so that one of the transmembrane helices moves to lock the cytoplasmic gate of the transmembrane Ca2+-binding sites. This appears to be the mechanism for occluding the bound Ca2+ ions, before releasing them into the lumen of the sarcoplasmic reticulum.
About this Structure
1VFP is a Single protein structure of sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA.
Reference
Crystal structure of the calcium pump with a bound ATP analogue., Toyoshima C, Mizutani T, Nature. 2004 Jul 29;430(6999):529-35. Epub 2004 Jun 30. PMID:15229613 Page seeded by OCA on Sat May 3 12:29:29 2008
