Total Chemical Synthesis of Crambin

Duhee Bang, Neeraj Chopra, Stephen B.H. Kent

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


Crambin is a small (46 amino acids) protein isolated from the seeds of the plant Crambe abyssinica. Crambin has been extensively used as a model protein for the development of advanced crystallography and NMR techniques and for computational folding studies. We set out to establish synthetic access to crambin. Initially, we synthesized the 46 amino acid polypeptide by native chemical ligation of two distinct sets of peptide segments (15 + 31 and 31 + 15 residues). The synthetic polypeptide chain folded in good yield to give native crambin containing three disulfide bonds. The chemically synthesized crambin was characterized by LC-MS and by 2D-NMR. However, the 31-residue peptide segments were difficult to purify, and this caused an overall low yield for the synthesis. To overcome this problem, we synthesized crambin by the native chemical ligation of three segments (15 + 16 + 15 residues). Total synthesis using the ligation of three segments gave more than a 10-fold increase in yield and a protein product of exceptionally high purity. This work demonstrates the efficacy of chemical protein synthesis by the native chemical ligation of three segments and establishes efficient synthetic access to the important model protein crambin for experimental studies of protein folding and stability.

Original languageEnglish
Pages (from-to)1377-1383
Number of pages7
JournalJournal of the American Chemical Society
Issue number5
Publication statusPublished - 2004 Feb 11

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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