1TUG
Aspartate Transcarbamoylase Catalytic Chain Mutant E50A Complex with Phosphonoacetamide, Malonate, and Cytidine-5-Prime-Triphosphate (CTP)
Summary for 1TUG
| Entry DOI | 10.2210/pdb1tug/pdb |
| Related | 1NBE 1TTH 1TU0 3AT1 |
| Descriptor | Aspartate carbamoyltransferase catalytic chain, Aspartate carbamoyltransferase regulatory chain, MALONATE ION, ... (7 entities in total) |
| Functional Keywords | protein structure-function, site specific mutagenesis, domain closure, allosteric transition, hydrolase-hydrolase regulator complex, hydrolase/hydrolase regulator |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 4 |
| Total formula weight | 104424.71 |
| Authors | Stieglitz, K.,Stec, B.,Baker, D.P.,Kantrowitz, E.R. (deposition date: 2004-06-24, release date: 2004-07-20, Last modification date: 2024-10-30) |
| Primary citation | Stieglitz, K.,Stec, B.,Baker, D.P.,Kantrowitz, E.R. Monitoring the Transition from the T to the R State in E.coli Aspartate Transcarbamoylase by X-ray Crystallography: Crystal Structures of the E50A Mutant Enzyme in Four Distinct Allosteric States. J.Mol.Biol., 341:853-868, 2004 Cited by PubMed Abstract: A detailed description of the transition that allosteric enzymes undergo constitutes a major challenge in structural biology. We have succeeded in trapping four distinct allosteric states of a mutant enzyme of Escherichia coli aspartate transcarbomylase and determining their structures by X-ray crystallography. The mutant version of aspartate transcarbamoylase in which Glu50 in the catalytic chains was replaced by Ala destabilizes the native R state and shifts the equilibrium towards the T state. This behavior allowed the use of substrate analogs such as phosphonoacetamide and malonate to trap the enzyme in T-like and R-like structures that are distinct from the T-state structure of the wild-type enzyme (as represented by the structure of the enzyme with CTP bound and the R-state structure as represented by the structure with N-(phosphonacetyl)-L-aspartate bound). These structures shed light on the nature and the order of internal structural rearrangements during the transition from the T to the R state. They also suggest an explanation for diminished activity of the E50A enzyme and for the change in reaction mechanism from ordered to random for this mutant enzyme. PubMed: 15288791DOI: 10.1016/j.jmb.2004.06.002 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.1 Å) |
Structure validation
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