Ligation of peptides

Chemoselective ligation of peptides using the free amino terminal as nucleophile and a thiobenzyl thioester C-terminal amino acid as electrophile provides an efficient approach to the synthesis of proteins with several hundred residues [30]. From this perspective the introduction of non-natural amino acids into proteins becomes a possibility rather than a problem and chemoselective ligation is thus a prospect for the future for the incorporation of new functionality. 

Abrahmsen, L., Tom, J., Bumier, J., Butcher, K.A., Kossiakoff, A. and Wells, J.A. (1991) Engineering subtihsin and its substrates for efficient ligation of peptide bonds in aqueous solution. Biochemistry, 30,4151 159. 

Scheme 16 Thiol-Thiol Exchange Reactions for Ligation of Peptides to the CoresI42-921...

Scheme 18 Synthesis of Peptide Dendrimers through Ligation of Peptides with a Weak Base to the Aldehyde...

Ligation of Peptide Dendrimers through Oxime, Hydrazone, and Thiazolidine Ligations To Form 64,66,... 

A product-capture strategy was also used to select improved subtiligases. Subtiligase is a double mutant of subtilisine that catalyses the ligation of peptides. A library of >109 variants involving 25 residues of the active site was constructed on the phage-displayed enzyme. Variants that ligated a biotinylated peptide on their own ex-... 

Also, template controlled ligation of peptide nucleic acids is possible using EDC in an imidazole buffer. The highest selectivity is obtained using a peptide condensation that forms an abasic site. An example is the following reaction which produces the peptide 673. 

We reported site-specific ligation of peptides to a carrier protein or polymer before printing onto the glass slide with an automatic arrayer to form a peptide microarray (22). Recently, Dikmans et al. (23) reported a novel process for manufacturing... 

A second example involves different evolved subtiligases. Subtilisins are proteolytic enzymes sutiligases are mutants that catalyzes the ligation of peptides. Evolved variants of subtiligase that ligate a biotinylated peptide onto their own extended N-termini were selectively captured, as shown in Figure 8.9. The reaction of the biotin-labeled peptide substrate with the evolved enzyme variant results in a... 

Typical Experimental Procedures for the Solid-Phase Native Ligation of Peptides... 

Fang GM, Wang JX, Liu L (2012) Convergent chemical synthesis of proteins by ligation of peptide hydrazides. Angew Chem Int Ed 51 10347-10350... 

Zheng J-S, Tang S, Guo Y, Chang H-N, Liu L (2012) Synthesis of cyclic peptides and cyclic proteins via ligation of peptide hydrazides. ChemBioChem 13 542-546... 

Fang GM, Cui HK, Zheng JS, Liu L (2010) Chemoselective ligation of peptide phenyl esters with N-teiminal cysteines. ChemBioChem 11 1061-1065... 

The 1,3-cycloaddition of alkyl azides to terminal alkynes is very slow, but can be catalyzed by Cu(l) (mechanism Straub, 2007)3 This formation of 1,2,3-triazoles, popularized as click reaction , was used by Sharpless and Meldal (both 2002) for the selective and biocompatible ligation of peptides, proteins, and especially for the introduction of biomarkers. In vivo applications in aqueous medium are feasible. The bioresearch community applauded this new tool which aroused fresh enthusiasm in azide chemistry. 

Chan W-K, Ho C-M, Wong M-K, Che C-M (2006) Oxidative amide synthesis and N-terminal a-amino group ligation of peptides in aqueous medium. J Am Chem Soc 128 (46) 14796-14797... 

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