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2-Acylamido Analogues of N-Acetylglucosamine Prime Formation of Chitin Oligosaccharides by Yeast Chitin Synthase 2
- Jacob Gyore, Archana R. Parameswar, Carleigh F. F. Hebbard, Younghoon Oh, Erfel Bi, Alexei V. Demchenko, Neil P. Price, Peter Orlean
- Journal of biological chemistry 2014 v.289 no.18 pp. 12835-12841
- N-acetylglucosamine, cell walls, chitin, chitin synthase, chitooligosaccharides, disaccharides, mass spectrometry, polymers, synthesis, yeasts
- Chitin, a polymer of beta-1,4-linked N-acetylglucosamine (GlcNAc), is a key component of the cell walls of fungi and the exoskeletons of arthropods. Chitin synthases (CSs) transfer GlcNAc from UDP-GlcNAc to pre-existing chitin chains in reactions that are typically stimulated by free GlcNAc. The effect of GlcNAc was probed by using a yeast strain expressing a single chitin synthase, Chs2, by examining formation of chitin oligosaccharides (COs) and insoluble chitin, and by replacing GlcNAc with 2-amido analogues of GlcNAc. Synthesis of COs was strongly dependent on inclusion of GlcNAc in CS incubations, and GlcNAc2 was the major reaction product. Formation of both COs and insoluble chitin was also stimulated by di-N-acetylchitobiose and by N-propionyl-, N-butanoyl-, and N-glycolylglucosamine. Mass spectrometric analyses of the COs made in the presence of 2-amido analogues of GlcNAc showed they contained a single GlcNAc analogue, and one or more additional GlcNAc residues. These results indicate that Chs2 can use certain 2-amido analogues of GlcNAc, and likely free GlcNAc and GlcNAc2 as well, as GlcNAc acceptors in a UDP-GlcNAc-dependent glycosyltransfer reaction. Further, formation of modified disaccharides indicates that CSs can transfer single GlcNAc residues.