The Structure and Catalytic Cycle of a Sodium-Pumping Pyrophosphatase

Abstract

View of a Sodium Pump Membrane-integral pyrophosphatases (M-PPases) found in plants, protozoans, bacteria, and archaea, link pyrophosphate hydrolysis or synthesis to sodium or proton pumping and contribute to generating an electrochemical potential across the membrane. Kellosalo et al. (p. 473 ) report the structure of the sodium pumping M-PPase from Thermotoga maritima in the resting state with product bound. The structures reveal the conformational changes that are likely to accompany pyrophosphate binding and provide insight into the ion-pumping mechanism.