Imaging the native structure of the chaperone protein GroEL without fixation using atomic force microscopy

Area of Science:

• Biophysics
• Structural Biology
• Microscopy Techniques

Background:

• Traditional microscopy sample preparation often involves fixation, which can alter biomolecular structure and function.
• Preserving native protein structure and activity is crucial for understanding biological processes.

Purpose of the Study:

• To develop and demonstrate a sample preparation method for imaging unfixed proteins under in-vivo conditions.
• To visualize the native structure and potential activity of the GroEL protein complex.

Main Methods:

• Utilized atomic force microscopy (AFM) for high-resolution imaging.
• Developed specific sample preparation conditions to maintain proteins in a near-native, unfixed state.
• Performed imaging under simulated in-vivo conditions.

Main Results:

• Successfully imaged the unfixed GroEL protein, revealing its characteristic toroidal shape and central pore.
• Obtained high-resolution images of single GroEL complexes with dimensions consistent with crystallographic data.
• Demonstrated that the protein maintained its native structure during imaging.

Conclusions:

• The developed method allows for the imaging of unfixed proteins, preserving their native structure and biological activity.
• This technique opens possibilities for studying protein function and dynamics under biologically relevant conditions.
• Atomic force microscopy under these conditions provides valuable insights into protein structure-function relationships.