Atomic force microscopy of the myosin molecule

Area of Science:

• Biophysics
• Structural Biology
• Molecular Motors

Background:

• Myosin is a crucial protein for muscle contraction.
• Understanding myosin's structure is key to muscle function.
• Previous structural studies often relied on electron microscopy.

Purpose of the Study:

• To investigate the structure of rabbit skeletal muscle myosin.
• To evaluate the glycerol-mica technique for protein preparation.
• To utilize atomic force microscopy (AFM) for high-resolution imaging.

Main Methods:

• Rabbit skeletal muscle myosin was deposited onto mica from glycerol solution.
• Contact mode AFM was employed with the sample immersed in propanol.
• Imaging and force application were used to analyze molecular structure.

Main Results:

• Myosin molecules displayed a characteristic two-headed structure with a long tail.
• The average tail length measured 155 +/- 5 nm, consistent with prior research.
• Applied force allowed for local separation of the alpha-helical coiled-coil tail strands.

Conclusions:

• The glycerol-mica technique is suitable for preparing fibrous proteins for scanning probe microscopy.
• AFM provides valuable insights into myosin's molecular architecture.
• The study confirms and refines structural observations of myosin previously made with electron microscopy.