Skip residues correlate with bends in the myosin tail

Area of Science:

• Molecular biology
• Biochemistry
• Structural biology

Background:

• Myosin molecules exhibit sharp bends in their tails at specific locations.
• Previous models of myosin tail structure did not fully explain these observed bends.

Purpose of the Study:

• To investigate the structural basis for sharp bends in skeletal and smooth myosin tails.
• To reconcile observed bending patterns with revised models of myosin heavy chain structure.

Main Methods:

• Analysis of revised myosin tail models, incorporating skip residues.
• Correlation of skip residue positions with observed bend locations in skeletal and smooth myosin.

Main Results:

• Observed bends in skeletal myosin tails align with three of the four skip residues.
• Smooth myosin lacks a bend at 75 nm, corresponding to its lack of the second skip residue.
• Skip residues cause localized instability in the coiled-coil structure, leading to bends.

Conclusions:

• Skip residues are responsible for the sharp bends observed in myosin tails.
• The presence or absence of specific skip residues explains differences in bending between skeletal and smooth myosin.