Gap junction structures. VI. Variation and conservation in connexon conformation and packing

Area of Science:

• Biophysics
• Structural Biology
• Cell Biology

Background:

• Understanding gap junction channel gating is crucial but hindered by isolation artifacts and lack of direct functional assays.
• Structural variations in isolated gap junctions complicate correlations with gating mechanisms.

Purpose of the Study:

• To investigate the impact of different isolation procedures on gap junction structure.
• To identify stable structural features of connexons and variable properties related to function or experimental modifications.

Main Methods:

• Comparative analysis of X-ray diffraction data from over 200 isolated gap junction specimens.
• Examination of structural parameters including subunit tilt, lattice symmetry, packing, and membrane curvature.

Main Results:

• Identified invariant aspects of connexon structure across different isolation protocols.
• Observed variable properties potentially related to functional switching or experimental artifacts.
• Demonstrated a correlation between connexon structure, interactions, and membrane curvature.

Conclusions:

• Membrane curvature may arise naturally from connexon structure and their interaction patterns.
• Distinguishing functional structural changes from experimental modifications is essential for understanding gap junction gating.