The 3D structures of VDAC represent a native conformation.

The most abundant protein of the mitochondrial outer membrane is the voltage-dependent anion channel (VDAC), which facilitates the exchange of ions and molecules between mitochondria and cytosol and is regulated by interactions with other proteins and small molecules. VDAC has been studied extensively for more than three decades, and last year three independent investigations revealed a structure of VDAC-1 exhibiting 19 transmembrane beta-strands, constituting a unique structural class of beta-barrel membrane proteins. Here, we provide a historical perspective on VDAC research and give an overview of the experimental design used to obtain these structures. Furthermore, we validate the protein refolding approach and summarize the biochemical and biophysical evidence that links the 19-stranded structure to the native form of VDAC.