TALE proteins search DNA using a rotationally decoupled mechanism

Area of Science:

• Molecular Biology
• Biophysics
• Genetics

Background:

• Transcription activator-like effector (TALE) proteins are crucial for gene editing.
• The precise mechanism by which TALEs search for specific DNA sequences remains largely unknown.

Purpose of the Study:

• To elucidate the sequence search mechanism of TALE proteins using single-molecule experiments.
• To understand how TALEs achieve efficient DNA binding and search.

Main Methods:

• Single-molecule experiments were employed to observe TALE protein interactions with DNA.
• Investigated TALE search dynamics along DNA templates under various solution conditions.

Main Results:

• TALEs employ a rotationally decoupled mechanism for nonspecific DNA search while maintaining association with the DNA template.
• The helical structure of TALEs facilitates a loosely wrapped conformation, enabling rapid one-dimensional (1D) diffusion.
• This mechanism aligns with a two-state model, resolving the search speed-stability paradox.

Conclusions:

• TALE protein DNA search is unique among sequence-specific DNA-binding proteins.
• The observed mechanism supports efficient 1D search crucial for gene editing applications.