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Native chemical ligation combined with desulfurization has become a powerful strategy for the chemical synthesis of proteins. Here we describe the use of a new thiol additive, methyl thioglycolate, to accomplish one-pot native chemical ligation and metal-free desulfurization for chemical protein synthesis. This one-pot strategy was used to prepare ubiquitin from two or three peptide segments. Circular dichroism spectroscopy and racemic protein X-ray crystallography confirmed the correct folding of ubiquitin. Our results demonstrate that proteins synthesized chemically by streamlined 9-fluorenylmethoxycarbonyl (Fmoc) solid-phase peptide synthesis coupled with a one-pot ligation-desulfurization strategy can supply useful molecules with sufficient purity for crystallographic studies. [ABSTRACT FROM AUTHOR]

We synthesized a lysine-linked auxiliary-derived building block, ϵ- N-2-mercapto-1-(2,4-dimethoxyphenyl)ethyl lysine, in 20 % isolated yield over a six-step route. The new building block is well compatible with Fmoc solid-phase peptide synthesis (SPPS) and hydrazide-based native chemical ligation (NCL). Furthermore, we successfully incorporated the new lysine-linked auxiliary handle into a protein segment and performed the chemical synthesis of K48-linked diubiquitin with stepwise NCL. [ABSTRACT FROM AUTHOR]

Mambalgins are a class of 57-residue polypeptide toxins isolated from the venom of the African mamba. They exhibit potent analgesic effects by inhibiting the acid-sensing ion channels. Classified as members of the family of three-finger toxins, mambalgins contain four pairs of disulfide bridges that help to stabilize the three-finger scaffold. Here, we report the chemical synthesis of functional mambalgin-1/2/3 by using one-step two-segment hydrazide-based native chemical ligation. The two-segment ligation approach reported here may enable efficient production of mambalgin toxins. These synthetic mambalgins are useful compounds for development of diagnostic or therapeutic reagents. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The NY-ESO-1 (A39-A68) peptide hydrazide was prepared through 9-fluorenyl-methoxycarbonyl solid-phase peptide synthesis (Fmoc SPPS) from a new 9-fluorenyl-methoxycarbonyl hydrazine 2-chlorotrityl chloride (Fmoc-hydrazine 2CTC) resin. The new resin was ideal for long-term storage and usage in Fmoc SPPS. Besides, the title peptide hydrazide could be transformed nearly quantitatively into the corresponding peptide thioester, which was both isolable and usable directly in native chemical ligation (NCL). [Copyright &y& Elsevier]