FIG 3.
Ammonium assimilation from l-aspartate using DcuA-AspA for uptake and intracellular ammonium release, ammonium assimilation by GS-GOGAT, and the GlnB regulatory system. The scheme shows the uptake of l-aspartate by DcuA and ammonium release by the DcuA-AspA metabolon, the ammonium assimilation via the common GS-GOGAT pathway yielding L-Glu, and the regulation of AspA by the GlnB regulatory system and regulatory factors. N↓, nitrogen-limited conditions; N↑, nitrogen-saturated conditions; 2-OG, 2-oxoglutarate; UTP, uridine-triphosphate; PPi, diphosphate; Pi, phosphate; UMP, uridine-monophosphate; GlnD, uridylyltransferase/uridylyl-removing enzyme; Fum, fumarate; PII, nitrogen regulator GlnB; DcuA, aerobic l-aspartate transporter; AspA, aspartate ammonium-lyase; GS, glutamine synthetase GlnA; GOGAT, glutamine 2-oxoglutarate aminotransferase GltBD.