Correlated cryogenic photoactivated localization microscopy and cryo-electron tomography

Area of Science:

• Cellular and molecular biology
• Microscopy techniques
• Structural biology

Background:

• Cryo-electron tomography (CET) provides high-resolution 3D cell imaging.
• Identifying specific structures within crowded cellular environments is difficult with CET alone.

Purpose of the Study:

• To develop a correlative imaging method combining cryo-electron tomography and cryo-photoactivated localization microscopy (cryo-PALM).
• To enhance the localization accuracy of cellular structures within cryo-tomograms.

Main Methods:

• Correlated cryo-photoactivated localization microscopy-cryo-electron tomography (cryo-PALM-CET) was employed.
• This technique integrates light microscopy localization with electron tomography for high-resolution 3D structural analysis.

Main Results:

• The cryo-PALM-CET method successfully localized objects within cryo-tomograms beyond the diffraction limit.
• Multiple and previously unknown conformations of the type VI secretion system were identified.
• These structures were observed in the complex cellular interior of Myxococcus xanthus.

Conclusions:

• Correlated cryo-PALM-CET is an effective method for precise structural localization in cryo-tomography.
• The technique facilitates the study of dynamic macromolecular machines, such as the type VI secretion system, in their native cellular context.