Structural insight into co-translational membrane protein folding

Membrane protein folding studies lag behind those of water-soluble proteins due to immense difficulties of
experimental study, resulting from the need to provide a hydrophobic lipid-bilayer environment when investigated
in vitro. A sound understanding of folding mechanisms is important for membrane proteins as they
contribute to a third of the proteome and are frequently associated with disease when mutated and/or misfolded.
Membrane proteins largely consist of α-helical, hydrophobic transmembrane domains, which insert into the
membrane, often using the SecYEG/Sec61 translocase system. This mini-review highlights recent advances in
techniques that can further our understanding of co-translational folding and notably, the structure and insertion
of nascent chains as they emerge from translating ribosomes.