Fig. 4: The cooperative model of the Pma1 hexamer.
From: Structure and activation mechanism of the hexameric plasma membrane H+-ATPase
a Structural comparison of the Pma1 subunit in autoinhibited and activated E2P states. TMH1–2 move downward by 6.7 Å and rotate by 40°. b Structural model of the autoinhibited Pma1 hexamer, in which one protomer is replaced by the activated Pma1. The red rectangle highlights the region in which two neighboring P-domains would sterically clash. c A proposed cooperative activation model of the Pma1 hexamer. When one protomer in the Pma1 hexamer is activated, this protomer induces the activation of the next protomer by releasing its helix-i from the neighboring P-domain. Sequential release of the helices-i around the hexamer leads to the activation of all six protomers.
