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

ABSTRACT: X-ray crystallography and small-angle X-ray scattering (SAXS) in solution have been used to show that a mutant aspartate transcarbamoylase exists in an intermediate quaternary structure between the canonical T and R structures. Additionally, the SAXS data indicate a pH-dependent structural alteration consistent with either a pH-induced conformational change or a pH-induced alteration in the T to R equilibrium. These data indicate that this mutant is not a model for the R state, as has been proposed, but rather represents the enzyme trapped along the path of the allosteric transition between the T and R states.

SUBMITTER: Guo W 

PROVIDER: S-EPMC3356622 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature