Myoglobin cavities provide interior ligand pathway

Area of Science:

• Biochemistry
• Structural Biology
• Protein Dynamics

Background:

• Myoglobin is a key model protein for studying oxygen binding and NO oxidation.
• Understanding ligand movement within myoglobin is crucial but challenging.
• Previous studies utilized spectroscopy, crystallography, and simulation.

Purpose of the Study:

• To visualize the mechanism of ligand motion within myoglobin.
• To analyze the role of protein substates in myoglobin function.
• To identify conserved pathways relevant to human neuroglobin.

Main Methods:

• Generated correlated residue clusters from crystal structures (1a6g) for A1 and A3 states.
• Analyzed internal cavities in A1 and A3 myoglobin conformations.
• Compared structural conservation with human neuroglobin.

Main Results:

• Identified a clear pathway for ligand motion from distal to proximal heme side.
• Discovered that internal cavities link distal and proximal sides via alternate conformations.
• Highlighted structural conservation of this pathway in human neuroglobin.

Conclusions:

• Cavity migration in myoglobin crystal alternates links protein structure, dynamics, and function.
• Protein substates (discrete disorder) are relevant to protein function.
• The identified pathway is conserved and relevant to human neuroglobin.