1ZA1: Structure Of Wild-type E. Coli Aspartate Transcarbamoylase In The Presence Of Ctp At 2.20 A Resolution

X-ray structures of aspartate transcarbamoylase in the absence and presence of the first substrate carbamoyl phosphate are reported. These two structures in conjunction with in silico docking experiments provide snapshots of critical events in the function of the enzyme. The ordered substrate binding, observed experimentally, can now be structurally explained by a conformational change induced upon the binding of carbamoyl phosphate. This induced fit dramatically alters the electrostatics of the active site, creating a binding pocket for aspartate. Upon aspartate binding, a further change in electrostatics causes a second induced fit, the domain closure. This domain closure acts as a clamp that both facilitates catalysis by approximation and also initiates the global conformational change that manifests homotropic cooperativity.
PDB ID: 1ZA1Download
MMDB ID: 33826
PDB Deposition Date: 2005/4/5
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 1ZA1: dodecameric; determined by author and by software (PISA,PQS)
Molecular Components in 1ZA1
Label Count Molecule
Proteins (12 molecules)
Aspartate Carbamoyltransferase Catalytic Chain
Molecule annotation
Aspartate Carbamoyltransferase Regulatory Chain
Molecule annotation
Chemicals (12 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB