Cross-kymography analysis to simultaneously quantify the function and morphology of the archaellum

Area of Science:

• Microbiology
• Biophysics
• Structural Biology

Background:

• Helical structures are crucial for motility in many microorganisms, including bacterial flagella and the archaeal archaellum.
• The archaellum, though functionally similar to bacterial flagella, shares structural resemblance with type IV pili.
• Previous studies indicated right-handed archaella drive archaeal cell movement via rotation, but lacked detailed temporal and morphological data.

Purpose of the Study:

• To clarify the shape and rotational dynamics of the archaellum during archaeal swimming.
• To overcome limitations of previous methods in resolving the structure and motor properties of freely moving helical filaments.
• To introduce and demonstrate the utility of cross-kymography analysis for studying microbial motility structures.

Main Methods:

• Development and application of "cross-kymography analysis" for long-term observation of helical structures.
• Utilizing total internal reflection fluorescence microscopy to capture high-resolution dynamic data.
• Quantifying both the function and morphology of the archaellum simultaneously.

Main Results:

• Cross-kymography analysis provides unprecedented temporal resolution and signal quality for observing helical structures.
• The method enables simultaneous quantification of archaellum function (rotation) and morphology (shape).
• This technique overcomes previous challenges in studying freely swimming microorganisms in 3D space.

Conclusions:

• Cross-kymography analysis is a powerful new tool for characterizing microbial motility structures like the archaellum.
• Detailed insights into the archaellum's structure and motor function during swimming are now achievable.
• This advancement facilitates a deeper understanding of archaeal motility mechanisms.