A Model for the Molecular Mechanism of an Engineered Light-Driven Protein Machine

Area of Science:

• Biotechnology
• Molecular Biology
• Protein Engineering

Background:

• Controllable protein-based machines are crucial for biotechnology.
• Group II chaperonins are ATP-driven protein machines.
• Previous work re-engineered a chaperonin into a light-gated nanocage.

Purpose of the Study:

• To develop and test a molecular mechanism model for a light-gated chaperonin nanocage.
• To understand how light triggers conformational changes in the re-engineered protein.
• To provide a design principle for novel light-driven protein machines.

Main Methods:

• All-atom molecular simulations (in silico experiments).
• Site-specific attachment of an azobenzene crosslinker.
• Design and testing of protein mutants for in vitro experiments.

Main Results:

• Simulations suggest crosslinker length changes couple to nucleotide-binding pocket rearrangements, causing cage opening.
• A mutant protein directly controlled by the crosslinker confirmed the model.
• Successful reversible photoswitching of the engineered protein was demonstrated in vitro.

Conclusions:

• The study provides a mechanistic model for light-induced conformational changes in group II chaperonins.
• The findings validate a design principle for engineering light-controllable protein machines.
• This work advances the development of sophisticated, light-responsive biomaterials and nanodevices.