Domain orientation in the N-Terminal PDZ tandem from PSD-95 is maintained in the full-length protein.

ABSTRACT: Tandem PDZ domains have been suggested to form structurally independent supramodules. However, dissimilarity between crystallography and NMR models emphasize their malleable conformation. Studies in full-length scaffold proteins are needed to examine the effect of tertiary interactions within their native context. Using single-molecule fluorescence to characterize the N-terminal PDZ tandem in PSD-95, we provide the first direct evidence that PDZ tandems can be structurally independent within a full-length scaffold protein. Molecular refinement using our data converged on a single structure with an antiparallel alignment of the ligand-binding sites. Devoid of interaction partners, single-molecule conditions captured PSD-95 in its unbound, ground state. Interactions between PDZ domains could

SUBMITTER: McCann JJ 

PROVIDER: S-EPMC3116789 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature