Chemical Synthesis of Interleukin‐2 and Disulfide Stabilizing Analogues

Abstract

Chemical protein synthesis allows the construction of well-defined structural variations and facilitates the development of deeper understanding of protein structure-function relationships and new protein engineering strategies. Herein, we report the chemical synthesis of interleukin-2 (IL-2) variants on a multimilligram scale and the formation of nonnatural disulfide mimetics that improve stability against reduction. The synthesis was accomplished by convergent KAHA ligations; the acidic conditions of KAHA ligation proved to be valuable for the solubilization of the hydrophobic segments of IL-2. The bioactivity of the synthetic IL-2 and its analogues were shown to be equipotent to recombinant IL-2 and exhibit improved stability against reducing agents.

Chemical Synthesis of the Sec-To-Cys Homologue of Human Selenoprotein F and Elucidation of Its Disulfide-pairing Mode

“…To this mixture, TCEP and VA-044 were added directly to achieve quantitative desulfurization at Cys75, leading to peptide 4 with excellent isolated yield (29.1 mg, 53.8% over two steps). And after HPLC purification, the Acm protection groups can be conveniently removed using AgOAc ( Murar et al, 2020 ), affording 5 with high isolated yield (14.2 mg, 49.0%, Figure 3A, d ).…”

Integration of C-Acylation in the Solid-Phase Synthesis of Peptides and Peptidomimetics Employing Meldrum’s Acid, Phosphorus, and Sulfur Ylides

“…In addition, small proteins and variants thereof have been synthesized through α-Ketoacidhydroxylamine (KAHA) ligations including C-terminal modifications of the Ubiquitin-fold modifier 1 (UFM1), glucagonlike peptide-1 (GLP-1), variants of interleukin-2 (IL-2), ubiquitinconjugating enzyme 9 (Ubc9), ubiquitin-conjugating enzyme H5a (UbcH5a), the Titan protein domain, human insulin variants, derivatives of interferon-induced transmembrane protein 3 nitrophorin and others (Scheme 30). [67][68][69][70][71][72][73][74][75][76][77] Fmoc or Boc Scheme 32. Synthesis of epoxides from aldehydes by C-C bond formation using selenium ylides 79…”

“…Scheme 30. Synthesis of small proteins and natural cyclopeptides based on C-acylation of sulfur ylides[67][68][69][70][71][72][73][74][75][76][77] 4 Miscellaneous ylides as acyl anion equivalents Besides phosphorus and sulfur ylides, ammonium ylides were reported to behave as acyl anion equivalents that undergo reactions with active electrophiles leading to new C-C bonds. Wang et.…”

“…Scheme 30 Synthesis of small proteins and natural cyclopeptides based on C-acylation of sulfur ylides[67][68][69][70][71][72][73][74][75][76][77] …”

Enabling chemical protein (semi)synthesis via reducible solubilizing tags (RSTs)

“…However, some peptides with hydrophobic residues or a tendency for selfassembly are very difficult for reversed phase HPLC purication. [22][23][24] Furthermore, they have poor solubility in ligating buffers, making the ligation difficult, if not impossible. Of course, membrane proteins are extremely difficult for total synthesis and handling.…”