Deprotonation Mechanism of NH4+ in the Escherichia coli Ammonium Transporter AmtB:Insight from QM and QM/MM Calculations

摘要

Ammonia is the primary nitrogen source for the biological synthesis of amino acids in microorganisms and plants.In animals and humans,renal and hepatic ammonia sequestration and excretion are of fundamental importance for the regulation of the systemic pH value and the functioning of the central nervous system.The weak base ammonia exists predominantly (> 99 %) in the form of the NH4+ cation under physiological conditions.