The plant plasma membrane H⁺-ATPase: proton translocation and regulation

 

The very high mobility of protons in aqueous solutions demands special features of membrane proton transporters to sustain efficient yet regulated proton transport across biological membranes. By the use of the chemical energy of ATP, plasma-membrane-embedded H⁺-ATPases extrude protons from cells of plants and fungi to generate electrochemical proton gradients.

A recently published crystal structure of a plasma membrane H(+)-ATPase contributes to our knowledge about the mechanism of these essential enzymes. Together with biochemical and structural data presented in this thesis we are now able to describe the basic molecular components that allow the plasma membrane proton H⁺-ATPase to carry out proton transport against large membrane potentials. Moreover, a completely new paradigm for post-translational activation of these proteins is presented. The talk will focus on the following themes:

The molecular mechanism of proton transport against high membrane potentials

 

A Novel Mechanism of P-type ATPase Autoinhibition Involving Both Termini of the Protein