Chemical synthesis and semisynthesis of membrane proteins.

Total chemical synthesis and semisynthesis of proteins have become widely used tools to alter and control the chemical structure of soluble proteins, Thus, offering unique possibilities to understand protein function in vitro and in vivo. However, these approaches rely on our ability to produce and chemoselectively link peptide segments with each other or with recombinantly produced protein segments. Access to integral membrane and membrane-associated proteins via these approaches has been hampered by the fact that integral membrane peptides or lipid-modified peptides are difficult to obtain mostly due to incomplete amino acid coupling reactions and their poor handling properties. This article will highlight the advances in the total chemical synthesis and semisynthesis of small viral as well as bacterial ion channels. Recent synthesis approaches for membrane-associated proteins will be discussed as well.