ACT domains located C-terminal to the catalytic domain of the lysine-sensitive aspartokinase isoenzyme AKIII
This CD includes the first of two ACT domains located C-terminal to the catalytic domain of the lysine-sensitive aspartokinase isoenzyme AKIII, a monofunctional class enzyme found in bacteria (Escherichia coli (EC) LysC). Aspartokinase is the first enzyme in the aspartate metabolic pathway and catalyzes the conversion of aspartate and ATP to aspartylphosphate and ADP. The E. coli AKIII (LysC) binds two feedback allosteric inhibitor lysine molecules at the dimer interface located between the ACT1 domain of two subunits. Members of this CD belong to the superfamily of ACT regulatory domains.
Structure:2J0X; E. coli aspartokinase AKIII dimer, in the inactive T-state with bound lysine; contacts of ACT1 domains with lysine. - View structure with Cn3D
Comment:defined by 3.5 Angstrom distance.
Comment:two feedback allosteric inhibitor lysine molecules are bound at the dimer interface located between the ACT1 domains of two subunits.
Comment:E. coli AKIII (2J0W) in the active R-state binds aspartate and ADP in the catalytic domain.
Comment:Comparison of R- and T-state AKIII indicates that binding of lysine to the regulatory ACT1 domain in R-state AKIII instigates a series of changes that release a "latch" from the catalytic domain, which in turn undergoes large rotational rearrangements, promoting tetramer formation and completion of the transition to the T-state.