3R7D

Crystal Structure of Unliganded Aspartate Transcarbamoylase from Bacillus subtilis

Summary for 3R7D

• Entry DOI: 10.2210/pdb3r7d/pdb
• Related: 3R7F 3R7L
• Descriptor: Aspartate carbamoyltransferase, PHOSPHATE ION (3 entities in total)
• Functional Keywords: aspartate transcarbamoylase, transferase, catalytic cycle
• Biological source: Bacillus subtilis
• Total number of polymer chains: 3
• Total formula weight: 103369.90

Authors

Puleo, D.E.,Harris, K.M.,Cockrell, G.M.,Kantrowitz, E.R. (deposition date: 2011-03-22, release date: 2011-06-08, Last modification date: 2024-02-21)

Primary citation

Harris, K.M.,Cockrell, G.M.,Puleo, D.E.,Kantrowitz, E.R.
Crystallographic Snapshots of the Complete Catalytic Cycle of the Unregulated Aspartate Transcarbamoylase from Bacillus subtilis.
J.Mol.Biol., 411:190-200, 2011

PubMed Abstract: Here, we report high-resolution X-ray structures of Bacillus subtilis aspartate transcarbamoylase (ATCase), an enzyme that catalyzes one of the first reactions in pyrimidine nucleotide biosynthesis. Structures of the enzyme have been determined in the absence of ligands, in the presence of the substrate carbamoyl phosphate, and in the presence of the bisubstrate/transition state analog N-phosphonacetyl-L-aspartate. Combining the structural data with in silico docking and electrostatic calculations, we have been able to visualize each step in the catalytic cycle of ATCase, from the ordered binding of the substrates, to the formation and decomposition of the tetrahedral intermediate, to the ordered release of the products from the active site. Analysis of the conformational changes associated with these steps provides a rationale for the lack of cooperativity in trimeric ATCases that do not possess regulatory subunits.

PubMed: 21663747
DOI: 10.1016/j.jmb.2011.05.036

Experimental method

X-RAY DIFFRACTION (2.196 Å)