Trapping and structure determination of an intermediate in the allosteric transition of aspartate transcarbamoylase.

Stabilization of the R allosteric structure of Escherichia coli aspartate transcarbamoylase by disulfide bond formation.

Here we report the first use of disulfide bond formation to stabilize the R allosteric structure of Escherichia coli aspartate transcarbamoylase. In the R allosteric state, residues in the 240s loop from two catalytic chains of different subunits are close together, whereas in the T allosteric state they are far apart. By substitution of Ala-241 in the 240s loop of the catalytic chain with cyst...

Binding of bisubstrate analog promotes large structural changes in the unregulated catalytic trimer of aspartate transcarbamoylase: implications for allosteric regulation.

A central problem in understanding enzyme regulation is to define the conformational states that account for allosteric changes in catalytic activity. For Escherichia coli aspartate transcarbamoylase (ATCase; EC) the active, relaxed (R state) holoenzyme is generally assumed to be represented by the crystal structure of the complex of the holoenzyme with the bisubstrate analog N-phosphonacetyl-L...

Can a simple model account for the allosteric transition of aspartate transcarbamoylase?

The contribution of individual interchain interactions to the stabilization of the T and R states of Escherichia coli aspartate transcarbamoylase.

Stabilization of the T and R allosteric states of Escherichia coli aspartate transcarbamoylase is governed by specific intra- and interchain interactions. The six interchain interactions between Glu-239 in one catalytic chain of one catalytic trimer with both Lys-164 and Tyr-165 of a different catalytic chain in the other catalytic trimer have been shown to be involved in the stabilization of t...

From allostery to mutagenesis: 20 years with aspartate transcarbamoylase.

Following the discovery by Gerhart & Pardee (1962) that aspartate transcarbamoylase (ATCase, EC 2.1.3.2) from Escherichiu coli is inhibited by CTP and that there is a sigmoidal dependence of activity on aspartate concentration, much effort has been focused on ATCase as an allosteric enzyme. In particular, research has been aimed at accounting for both the heterotropic effects (inhibition by CTP...