Inspired and stabilized by nature: ribosomal synthesis of the human voltage gated ion channel (VDAC) into 2D-protein-tethered lipid interfaces

We present an elegant synthesis and reconstitution approach for functional studies of voltage responsive membrane proteins. For such studies, we propose a planar architecture of an S-layer-supported lipid membrane as a suitable matrix for presenting unmodified membrane protein species, and here we focus on the voltage-dependent anion channel (VDAC) from human mitochondria. The presented cell-free strategy, in which VDAC proteins are synthesized in bacterial cell lysate, into a membrane structure, offers a great advantage in the study of such subtle membrane proteins over the conventional, cell-based synthesis approach in terms of reproducibility. The material-assay combination is superior over cell-culture related synthesis and purification approaches as here we bypass by a one-step synthesis procedure the complex cell culture, and expression and purification endeavours, and, moreover, the protein of interest never has to be detergent solubilized and had been synthesized de novo . We provide here a detailed description from the all over procedure and our first results, describing in detail the cell-free synthesis and robustness of such a material-assay combination: functional VDAC protein species embedded in a planar membrane architecture and ready for electrochemical characterization. The scheme of the cell-free, ribosomal synthesis of a VDAC protein in the presence of an S-layer supported lipid membrane. The VDAC protein is adapted from S. Hiller et al ., Science , 2008, 321 , 1206-1210.