3L76

Crystal Structure of Aspartate Kinase from Synechocystis

Summary for 3L76

• Entry DOI: 10.2210/pdb3l76/pdb
• Descriptor: Aspartokinase, THREONINE, LYSINE, ... (5 entities in total)
• Functional Keywords: aspartokinase, synechocystis, allostery, act domains, kinase, transferase
• Biological source: Synechocystis
• Total number of polymer chains: 2
• Total formula weight: 128357.06

Authors

Robin, A.,Cobessi, D.,Curien, G.,Robert-Genthon, M.,Ferrer, J.-L.,Dumas, R. (deposition date: 2009-12-28, release date: 2010-06-09, Last modification date: 2024-03-20)

Primary citation

Robin, A.Y.,Cobessi, D.,Curien, G.,Robert-Genthon, M.,Ferrer, J.-L.,Dumas, R.
A new mode of dimerization of allosteric enzymes with ACT domains revealed by the crystal structure of the aspartate kinase from Cyanobacteria
J.Mol.Biol., 399:283-293, 2010

PubMed Abstract: Aspartate kinases (AKs) can be divided in two subhomology divisions, AKalpha and AKbeta, depending on the presence of an extra sequence of about 60 amino acids, which is found only in the N-terminus of all AKalpha's. To date, the structures of AKalpha failed to provide a role for this additional N-terminal sequence. In this study, the structure of the AKbeta from the Cyanobacteria Synechocystis reveals that this supplementary sequence is linked to the dimerization mode of AKs. Its absence in AKbeta leads to the dimerization by the catalytic domain instead of involving the ACT domains [Pfam 01842; small regulatory domains initially found in AK, chorismate mutase and TyrA (prephenate dehydrogenase)] as observed in AKalpha. Thus, the structural analysis of the Synechocystis AKbeta revealed a dimer with a novel architecture. The four ACT domains of each monomer interact together and do not make any contact with those of the second monomer. The enzyme is inhibited synergistically by threonine and lysine with the binding of threonine first. The interaction between ACT1 and ACT4 or between ACT2 and ACT3 generates a threonine binding site and a lysine binding site at each interface, making a total of eight regulatory sites per dimer and allowing a fine-tuning of the AK activity by the end products, threonine and lysine.

PubMed: 20398676
DOI: 10.1016/j.jmb.2010.04.014

Experimental method

X-RAY DIFFRACTION (2.54 Å)