Dissection of Ammonium Uptake Systems in<i>Corynebacterium glutamicum</i>: Mechanism of Action and Energetics of AmtA and AmtB

Abstract

Corynebacterium glutamicum has two different Amt-type proteins. While AmtB has a low substrate affinity and is not saturable up to 3 mM methylammonium, AmtA has a high substrate affinity and mediates saturable, membrane potential-dependent transport, resulting in a high steady-state accumulation of methylammonium, even in the absence of metabolic trapping.