Sortase A-catalyzed peptide cyclization for the synthesis of macrocyclic peptides and glycopeptides

Abstract

A chemoenzymatic method was developed for the synthesis of macrocyclic peptides and glycopeptides. Sortase A was found to mediate either head to tail cyclization or oligomerization and then head to tail cyclization of peptides and glycopeptides, depending on the peptide length, to produce 15-mer or higher cyclic peptides and glycopeptides.

Semienzymatic Cyclization of Disulfide-rich Peptides Using Sortase A

“…We have shown that this method is applicable whether the peptides are cyclic in their native form, such as SFTI-1 containing one disulfide bond or kB1 with a three-disulfide bond cyclic cystine knot motif, or whether the peptide is linear in its native form and the cyclization site is introduced by the addition of a linker, such as for cVc1.1. SrtAmediated head-to-tail cyclization works optimally with peptides larger than 12-mers, excluding the SrtA sorting signal (40). Cyclotides are typically 28 -37 amino acids in size, making all characterized cyclotides suitable for SrtA cyclization.…”

“…Recently, a family of thiol-containing transpeptidases, known as the sortases, were found to successfully cyclize linear proteins (37)(38)(39)(40). Sortases are found in most Gram-positive bacteria, where their primary function is to attach surface proteins to the bacterial cell wall (41).…”

Sortase-mediated backbone cyclization of proteins and peptides

“…This provided an elegant new route to cyclize proteins and peptides (Antos et al, 2009;Bolscher et al, 2011;Wu et al, 2011).…”

“…The ratio cyclic product: multimeric product depends both on the size of the substrate and on the concentration. Wu et al (2011) found that for sortase A-catalyzed peptide cyclization the minimal size of substrate peptides is a 19-mer, including the sorting signal. With a 17-mer peptide a direct head-to tail cyclization product was obtained with 6% yield, whereas the major product was the cyclic dimer.…”

“…By increasing the substrate concentration, the yield of dimer and trimer products increased, whereas that of cyclic products decreased. The virtually complete conversion of 19-mer and longer peptides, even at relatively high substrate/enzyme ratios, suggests that for these substrates cyclization reaction is the preferred reaction (Wu et al, 2011). (B) Schematic representation of the molecular transpeptidation pathways.…”