Stepwise unfolding of ankyrin repeats in a single protein revealed by atomic force microscopy.

ABSTRACT: Using single-molecule atomic force microscopy, we find that a protein consisting of six identical ankyrin repeat units flanked by N- and C-terminal modules (N6C) unfolds in a stepwise, unit-by-unit fashion under a mechanical force. Stretching a N6C molecule results in a sawtooth pattern fingerprint, with as many as six peaks separated by approximately 10 nm and an average unfolding force of 50 +/- 20 pN. Our results demonstrate that a stretching force can unfold multiple repeat units individually in a single protein molecule, despite extensive hydrophobic interactions between adjacent units.

SUBMITTER: Li L 

PROVIDER: S-EPMC1367297 | biostudies-literature | 2006 Feb

REPOSITORIES: biostudies-literature