Figure 1
From: Attenuation of Streptococcus suis virulence by the alteration of bacterial surface architecture
Genetic organization of gene clusters and current working model for bacterial sialic acid biosynthetic pathway and subsequent metabolism.
(A) Genetic organization of the gene loci involved in de novo synthesis and utilization of bacterial sialic acids. neuB that encodes sialic acid synthetase is highlighted in golden-yellow. S. suis is indicated in red. The abbreviations are as follows: N. meningitidis for Neisseria meningitidis; C. jejuni for Campylobacter jejuni; E. coli for Escherichia coli; S. agalactiae for Streptococcus agalactiae; S. suis for Streptococcus suis and V. parahaemolyticus for Vibrio parahaemolyticus. (B) Working model for the biosynthetic route and metabolism of bacterial sialic acids. NeuB, sialic acid synthase is shown in golden-yellow and NeuNAc (also abbreviated as Neu5Ac, N-acetylneuraminic acid), a prevalent form of sialic acids is indicated in blue. NeuA terms as sialic acid O-acetylesterase, NeuC refers to UDP-GlcNAc 2-epimerase, NeuD is defined as sialic acid O-acetyltransferase12 and CpsK is an oligosaccharide α-2,3-sialyltransferase10,50. All other abbreviations are listed as follows: ManNAc, N-acetylmannosamine; GlcNAc, N-acetylglucosamine; UDP- GlcNAc, Uridine diphosphate N-acetylglucosamine; Neu5,7(9)Ac2, N-acetyl-7 or 9-O-acetylneuraminic acid; CMP-Neu5,7(9)Ac2, CMP-Neu5Ac, Cytidine monophosphate N-acetylneuraminic acid; Cytidine monophosphate N-acetyl-7 or 9-O-acetylneuraminic acid; CPS, Capsule polysaccharide. (C) Chemical structures of NeuNAc, the leading type of sialic acids in two existing states.
