Structural and functional characterization of Solanum tuberosum VDAC36

Area of Science:

• Biochemistry
• Molecular Biology
• Plant Science

Background:

• The voltage-dependent anion channel (VDAC) protein family is crucial for metabolite transport in eukaryotic cell mitochondria.
• Plant VDACs are less understood structurally and functionally compared to mammalian VDACs.

Purpose of the Study:

• To characterize the structural and functional properties of stVDAC36, an isoform of Solanum tuberosum VDAC.
• To investigate the oligomeric state and pore characteristics of stVDAC36.

Main Methods:

• Overexpression and refolding of stVDAC36.
• Circular dichroism and intrinsic fluorescence spectroscopy for structural analysis.
• Cross-linking, molecular modeling, liposome swelling assays, docking, and electrostatic calculations for functional and structural insights.

Main Results:

• Successfully overexpressed and refolded stVDAC36.
• Circular dichroism and fluorescence confirmed secondary and tertiary structures.
• Evidence for dimers and tetramers, suggesting a disulfide bond.
• Liposome assays indicated a pore diameter of 2.0–2.7 nm.
• Docking and electrostatic calculations provided insights into ATP binding.

Conclusions:

• stVDAC36 exists as dimers and tetramers, potentially involving disulfide bonds.
• The channel exhibits a defined pore size suitable for metabolite transport.
• Structural and functional characterization provides a foundation for understanding plant VDAC roles.