Solution NMR spectroscopic characterization of human VDAC-2 in detergent micelles and lipid bilayer nanodiscs

Three isoforms of the human voltage-dependent anion channel (VDAC), located in the outer mitochondrial membrane, are crucial regulators of mitochondrial function. Numerous studies have been carried out to elucidate biochemical properties, as well as the three-dimensional structure of VDAC-1. However, functional and structural studies of VDAC-2 and VDAC-3 at atomic resolution are still scarce. VDAC-2 is highly similar to VDAC-1 in amino acid sequence, but has substantially different biochemical functions and expression profiles. Here, we report the reconstitution of functional VDAC-2 in lauryldimethylamine-oxide (LDAO) detergent micelles and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayer nanodiscs. We find that VDAC-2 is properly folded in both membrane-mimicking systems and that structural and functional characterization by solution NMR spectroscopy is feasible. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism.

► The VDAC-2 isoform can be refolded in detergent micelles suitable for NMR spectroscopy.
► VDAC-2 can be reconstituted into phospholipid nanodiscs and is more stable than in micelles.
► VDAC-2 in nanodiscs is suitable for NMR structure determination with triple-resonance and NOE data.