Ubiquitin: preparative chemical synthesis, purification and characterization

An improved total synthesis of ubiquitin has been achieved by the Fmoc/t-butyl solid-phase methodology using NGPmc protection of the Arg residues. Optimization of the purification protocol has offered the material in substantial quantity (90 mg) in an overall yield of 4.2%. Characterization of the isolated products has opened the way to the studies of the folding pathway and the preparation of structural analogues.