- Accelerated Protein Synthesis via One-Pot Ligation-Deselenization Chemistry
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Peptide ligation chemistry has revolutionized protein science by facilitating access to synthetic proteins. Here, we describe the development of additive-free ligation-deselenization chemistry at β-selenoaspartate and γ-selenoglutamate that enables the generation of native polypeptide products on unprecedented timescales. The deselenization step is chemoselective in the presence of unprotected selenocysteine, which is highlighted in the synthesis of selenoprotein K. The power of the methodology is also showcased through the synthesis of three tick-derived thrombin-inhibiting proteins, each of which were assembled, purified, and isolated for biological assays within a few hours. The methodology described here should serve as a powerful means of accessing synthetic proteins, including therapeutic leads, in the future.
- Mitchell, Nicholas J.,Sayers, Jessica,Kulkarni, Sameer S.,Clayton, Daniel,Goldys, Anna M.,Ripoll-Rozada, Jorge,Barbosa Pereira, Pedro José,Chan, Bun,Radom, Leo,Payne, Richard J.
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supporting information
p. 703 - 715
(2017/05/15)
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- A comprehensive one-pot synthesis of protected cysteine and selenocysteine SPPS derivatives
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A proof-of-principle methodology is presented in which all commercially-available cysteine (Cys) and selenocysteine (Sec) solid phase peptide synthesis (SPPS) derivatives are synthesized in high yield from easily prepared protected dichalcogenide precursors. A Zn-mediated biphasic reduction process applied to a series of four bis-Nα-protected dichalcogenide compounds allows facile conversion to their corresponding thiol and selenol intermediates followed by insitu S- or Se-alkylation with various electrophiles to directly access twenty one known Cys and Sec SPPS derivatives. Most of these derivatives were able to be precipitated in crude form out of petroleum ether in sufficient purity for direct use as peptide building blocks. Subsequent incorporation of these derivatives into peptide models nicely illustrates their viability and applicability toward SPPS.
- Flemer, Stevenson
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p. 1257 - 1264
(2015/04/14)
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- The use of 2,2′-dithiobis(5-nitropyridine) (DTNP) for deprotection and diselenide formation in protected selenocysteine-containing peptides
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In contrast to the large number of sidechain protecting groups available for cysteine derivatives in solid phase peptide synthesis, there is a striking paucity of analogous selenocysteine Se-protecting groups in the literature. However, the growing interest in selenocysteine-containing peptides and proteins requires a corresponding increase in availability of synthetic routes into these target molecules. It therefore becomes important to design new sidechain protection strategies for selenocysteine as well as multiple and novel deprotection chemistry for their removal. In this paper, we outline the synthesis of two new Fmoc selenocysteine derivatives [Fmoc-Sec(Meb) and Fmoc-Sec(Bzl)] to accompany the commercially available Fmoc-Sec(Mob) derivative and incorporate them into two model peptides. Sec-deprotection assays were carried out on these peptides using 2,2′-dithiobis(5-nitropyridine) (DTNP) conditions previously described by our group. The deprotective methodology was further evaluated as to its suitability towards mediating concurrent diselenide formation in oxytocin-templated target peptides. Sec(Mob) and Sec(Meb) were found to be extremely labile to the DTNP conditions whether in the presence or absence of thioanisole, whereas Sec(Bzl) was robust to DTNP in the absence of thioanisole but quite labile in its presence. In multiple Sec-containing model peptides, it was shown that bis-Sec(Mob)-containing systems spontaneously cyclize to the diselenide using 1eq DTNP, whereas bis-Sec(Meb) and Sec(Bzl) models required additional manipulation to induce cyclization.
- Schroll, Alayne L.,Hondal, Robert J.,Flemer, Stevenson
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p. 155 - 162
(2012/05/20)
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