Two-dimensional crystalline arrays of Na,K-ATPase with new subunit interactions induced by cobalt-tetrammine-ATP

Abstract

Purified membrane-bound Na,K-ATPase incubated with cobalt-tetrammine-ATP [Co(NH₃)₄ATP], which is a stable MgATP complex analog, shows two new types of membrane crystals, a new p21 form and a p4 form. The building blocks of the crystalline arrays correspond to (αβ)₂ dimers of the enzyme protein suggesting that α-α interaction may be important in the pumping process.