In vitro interconversion of the soluble and membrane-integrated forms of the Escherichia coli glucose enzyme II of the phosphoenolpyruvate-dependent sugar-transporting phosphotransferase system

Abstract

In previous publications, we have shown that integral membrane sugar permeases of the bacterial phosphotransferase system can exist in a 'soluble' (probably micellar) monomeric form (SII) as well as a membrane-integrated dimeric form (MII). We here show that the two forms of the his-tagged glucose permease of Escherichia coli can be interconverted in vitro. Conversion of MII to SII is promoted by (1) low protein concentration, (2) detergent, (3) high pH, and (4) phospholipase A2 treatment. Conversion of SII to MII is promoted by: (1) high protein concentration, (2) adherence to and elution from an Ni2+ column, (3) neutral pH, and (4) incorporation into phospholipid liposomes. Copyright © 2007 S. Karger AG.