A solution NMR study showing that active site ligands and nucleotides directly perturb the allosteric equilibrium in aspartate transcarbamoylase.

ABSTRACT: The 306-kDa aspartate transcarbamoylase is a well studied regulatory enzyme, and it has emerged as a paradigm for understanding allostery and cooperative binding processes. Although there is a consensus that the cooperative binding of active site ligands follows the Monod-Wyman-Changeux (MWC) model of allostery, there is some debate about the binding of effectors such as ATP and CTP and how they influence the allosteric equilibrium between R and T states of the enzyme. In this article, the binding of substrates, substrate analogues, and nucleotides is studied, along with their effect on the R-T equilibrium by using highly deuterated, (1)H,(13)C-methyl-labeled protein in concert with methyl-transverse relaxation optimized spectroscopy (TROSY) NMR. Although only the T state of the enzyme can

SUBMITTER: Velyvis A 

PROVIDER: S-EPMC1885585 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature