Synthesis of Human Interleukin-8 by Native Chemical Ligation

P. E. DAWSON, T. W. MUIR, I. CLARK-LEWIS, S. B. KENT* (THE SCRIPPS RESEARCH Category INSTITUTE, LA JOLLA, USA) Chemistry in Synthesis of Proteins by Native Chemical Ligation Medicine and Science 1994, 266, 776–779. Biology

Synthesis of Human Interleukin-8 by Native Chemical Key words

Ligation peptide synthesis

native chemical ligation

Principle of native chemical ligation (NCL): protein synthesis O O human interleukin 8 Unprotected peptide H3N peptide-1 SR peptide-2 segments C-terminal thioester N-terminal cysteine S

chemoselective thioesterification

O O H2N Intermediate thioester peptide-1 peptide-2 linkage S

spontaneous amide bond formation

O O Final ligated product with peptide-1 N peptide-2 native amide bond H

Synthesis of human interleukin 8 (IL-8) via NCL:

O O O H N 3 – H3N IL-8 (1-33) SBn + IL-8 (35-72) O

HS SH HS SH

⋅ 6 M guanidine HCl, BnSH ca. 61% yield peptide fragments pH 7.6 phosphate buffer obtained by SPPS

O O O

– H3N IL-8 (1-33) N IL-8 (35-72) O H

HS SH HS SH

air, 1 M guanidine⋅HCl folding and disulfide formation pH 8.5 tris buffer

O O O

– H3N IL-8 (1-33) N IL-8 (35-72) O H

S S This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. S S IL-8

Significance: The realization that unprotected Comment: NCL proceeds by the formation of an peptide thioesters react chemoselectively with un- intermediate thioester linkage with cysteine that protected N-terminal cysteine residues to form am- then spontaneously rearranges to the native amide ide linkages is an important advancement in pro- bond. This strategy was applied to the total chemi- tein synthesis. Native Chemical Ligation (NCL) cal synthesis of human interleukin 8 (IL-8), a 72- allows synthetic access to proteins of moderate amino acid protein containing four cysteine resi- size. dues.

SYNFACTS Contributors: Dirk Trauner, Julius R. Reyes Synfacts 02042019, 15(04), 0439 Published online: 19.03.20191861-19581861-194X