Fig. 5: Chemical synthesis of LDLa using CSY. | Nature Communications

Fig. 5: Chemical synthesis of LDLa using CSY.

From: Prevention of aspartimide formation during peptide synthesis using cyanosulfurylides as carboxylic acid-protecting groups

Fig. 5: Chemical synthesis of LDLa using CSY.The alternative text for this image may have been generated using AI.

a Sequence of LDLa 11 with sequence motifs that are prone to aspartimide formation are highlighted. Z = pyroglutamic acid. b SPPS was carried out using standard conditions. Synthesis with conventional tert-butyl ester protected Asp was not successful, whereas LDLa(StBu/CSY) 12 was observed as major product using Fmoc-Asp(CSY)OH 3 monomers. c In solution deprotection of cyanosulfurylides using a stoichiometric amount of NCS provides LDLa(StBu) 13 in good yield (75%). Cysteines were deprotected using TCEP (20 mM) in PBS/CH3CN (9:1) giving unfolded LDLa 14 (55%) that was folded to provide LDLa 11 (36%). Detailed folding conditions for 14 are provided in Methods and Supplementary Figs. 11 and 12.

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