Cell-free expression and labeling strategies for a new decade in solid-state NMR

Although solid-state NMR and cell-free expression have recently become standard methods in biology, the combination of the two is still at a very early stage of development. In this article, we will explore several approaches by which cell-free expression could help solid-state NMR in its quest for biomolecular structure and mechanism elucidation. Far from being just another structure determination technique, this quest is motivated by the unique possibility of using solid-state NMR to determine the high resolution structure of a membrane protein within its native environment, the lipid membrane. We will examine the specific sample preparation requirements that such a goal imposes and how cell-free expression can play a key role in such a protocol.