1t5t
From Proteopedia
Structure of the (SR)Ca2+-ATPase Ca2-E1-ADP:AlF4- form
Overview
A tight coupling between adenosine triphosphate (ATP) hydrolysis and vectorial ion transport has to be maintained by ATP-consuming ion pumps. We report two crystal structures of Ca2+-bound sarco(endo)plasmic reticulum Ca2+-adenosine triphosphatase (SERCA) at 2.6 and 2.9 angstrom resolution in complex with (i) a nonhydrolyzable ATP analog [adenosine (beta-gamma methylene)-triphosphate] and (ii) adenosine diphosphate plus aluminum fluoride. SERCA reacts with ATP by an associative mechanism mediated by two Mg2+ ions to form an aspartyl-phosphorylated intermediate state (Ca2-E1 approximately P). The conformational changes that accompany the reaction with ATP pull the transmembrane helices 1 and 2 and close a cytosolic entrance for Ca2+, thereby preventing backflow before Ca2+ is released on the other side of the membrane.
About this Structure
1T5T is a Single protein structure of sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA.
Reference
Phosphoryl transfer and calcium ion occlusion in the calcium pump., Sorensen TL, Moller JV, Nissen P, Science. 2004 Jun 11;304(5677):1672-5. PMID:15192230 Page seeded by OCA on Sat May 3 09:33:46 2008
