Single-molecule experiments reveal the flexibility of a Per-ARNT-Sim domain and the kinetic partitioning in the unfolding pathway under force.

ABSTRACT: Per-ARNT-Sim (PAS) domains serve as versatile binding motifs in many signal-transduction proteins and are able to respond to a wide spectrum of chemical or physical signals. Despite their diverse functions, PAS domains share a conserved structure. It has been suggested that the structure of PAS domains is flexible and thus adaptable to many binding partners. However, direct measurement of the flexibility of PAS domains has not yet been provided. Here, we quantitatively measure the mechanical unfolding of a PAS domain, ARNT PAS-B, using single-molecule atomic force microscopy. Our force spectroscopy results indicate that the structure of ARNT PAS-B can be unraveled under mechanical forces as low as ~30 pN due to its broad potential well for the mechanical unfolding transition of ~2 nm. This

SUBMITTER: Gao X 

PROVIDER: S-EPMC3341564 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature