Fig. 2: Retrosynthetic analysis of O-GalNAc glycans.
From: Chemoenzymatic modular assembly of O-GalNAc glycans for functional glycomics
a Retrosynthetic analysis of O-GalNAc cores with three synthetic building blocks. b Retrosynthetic analysis of O-GalNAc epitopes with 13 enzyme modules. Enzyme modules: G stands for galactosylation, S stands for sialylation, N stands for N-acetylhexosaminylation, F stands for fucosylation. G1: β1-4 galactosylation with Neisseria meningitidis β1-4 galactosyltransferase (NmLgtB)47 and donor uridine 5′-diphosphogalactose (UDP-Gal); G2: α1–3 galactosylation with human GTB and UDP-Gal; G3: α1-3 galactosylation with bovine α1-3 GalT (Bα3GalT)48 and UDP-Gal; S1: α2-3 sialylation with Pasteurella multocida α2-3 sialyltransferase 1 mutant M144D (PmST1-M144D)52, N. meningitidis CMP-sialic acid synthetase (NmCSS)69, cytidine 5′-triphosphate (CTP), and N-acetylneuraminic acid (Neu5Ac); S2: α2-6 sialylation with PmST1-P34H/M144L49, NmCSS, CTP, and Neu5Ac; S3: α2–6 sialylation with Photobacterium damselae α2–6 sialyltransferase (Pd2,6ST)50, NmCSS, CTP, and Neu5Ac; S4: α2-6 sialylation with human ST6GalNAc-IV, NmCSS, CTP, and Neu5Ac; N1: β1-4 N-acetylgalactosaminylation with Campylobacter jejuni β1-4 N-acetylgalatosaminyltransferase (CjCgtA)70 and uridine 5′-diphosphate-N-acetylgalactosamine (UDP-GalNAc); N2: α1-3 N-acetylgalactosaminylation with Helicobacter mustelae α1-3 N-acetyl-galactosaminyltransferase (HmBgtA)56 and UDP-GalNAc; N3: β1-3 N-acetylglucosaminylation with Helicobacter pylori β1-3 N-acetylglucosaminyltransferase (HpLgtA)71 and uridine 5’-diphosphate-N-acetylglucosamine (UDP-GlcNAc); N4: β1-4 N-acetylgalactosaminylation with b4GalT-Y289L/C342T (b4GalTm)72 and UDP-GalNAc; F1: α1-2 fucosylation with H. mustelae α1-2 fucosyltransferase (Hm2FT)55 and guanosine 5′-diphospho-L-fucose (GDP-Fuc); F2: α1-3 fucosylation with H. pylori α1-3 fucosyltransferase C-terminal 66 amino acid truncation (Hp3FT)73 and GDP-Fuc. SF, Fmoc protected Ser.
