β-Methyl Galactoside System

β-Methyl Galactoside System

β-Methyl Galactoside System - Systems of this type depend on periplasmic substrate binding proteins, and are therefore highly sensitive to cold osmotic shock treatment which removes the proteins.

The system comprises galactose binding protein (GBP) and two non-binding proteins which are the products of the genes mgl A and mgl C. There is some evidence that the two genes are actually a single cistron.

According to one model the substrate is carried by the GBP, which bas a single substrate binding site like all binding proteins studied. GBP binds to a site on the inner membrane that includes the mgl A, C gene products and the exit carrier

ATP may be utilized to cause a conformational change in the GBP in a reaction catalysed by the mgl A, C product. The main source of energy for this system may not be Mitchell's proton motive force.

Some phosphate bound energy, possibly ATP itself, may be driving active transport

Home | Site map | Submit Article | Directory | Search