Crystallization (Comment) | Organism |
---|---|
ATCase locked in the R quaternary structure by specific introduction of disulfide bonds bound to the final product molecule phosphate, 10 mg/ml protein solution is dialyzed against a solution of 100 mM potassium dihydrogen phosphate and 3 mM sodium azide, pH 5.9, 1 week, X-ray diffraction structure determination and analysis at 2.85 A resolution, molecular replacement | Escherichia coli |
Protein Variants | Comment | Organism |
---|---|---|
C47A/A241C | the mutant holoenzyme with disulfides intact displays a hyperbolic Asp saturation curve confirming the loss of homotropic cooperativity, phosphate binding structure of the mutant, overview | Escherichia coli |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
N-phosphonacetyl-L-aspartate | - |
Escherichia coli |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-aspartate + carbamoyl phosphate | Escherichia coli | - |
phosphate + N-carbamoyl-L-aspartate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-aspartate + carbamoyl phosphate | - |
Escherichia coli | phosphate + N-carbamoyl-L-aspartate | - |
? | |
L-aspartate + carbamoyl phosphate | ATCase displays ordered substrate binding and product release, remaining in the R state until substrates are exhausted. Wild-type ATCase is in a T-state structure with bound product phosphate | Escherichia coli | phosphate + N-carbamoyl-L-aspartate | - |
? | |
additional information | in the structure of the enzyme trapped in the R state with specific disulfide bonds, two phosphate molecules are bound per active site. The position of the first phosphate corresponds to the position of the phosphate of carbamoyl phosphate and the position of the phosphonate of inhibitor N-phosphonacetyl-L-aspartate. However, the second, more weakly bound phosphate is bound in a positively charged pocket that is more accessible to the surface than the other phosphate. The second phosphate appears to be on the path that phosphate would have to take to exit the active site | Escherichia coli | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
aspartate transcarbamoylase | - |
Escherichia coli |
ATCase | - |
Escherichia coli |
General Information | Comment | Organism |
---|---|---|
metabolism | ATCase is an allosteric enzyme that catalyzes the committed step of pyrimidine nucleotide biosynthesis | Escherichia coli |
additional information | allosteric and kinetic structures, overview | Escherichia coli |
physiological function | allosteric transition of ATCase, R-state stabilization by disulfide linkages, overview. Wild-type ATCase displays homotropic cooperativity with respect to the second substrate Asp due a shift from the low-activity, low-affinity T state to the high-activity, high-affinity R state | Escherichia coli |