CARB 88 |
| Carbohydrates containing non-terminal sialic acid residues have been found mainly as surface polysaccharides (e.g. capsular polysaccharides or lipopolysaccharides) of some pathogenic bacteria and are believed to play important roles in the virulence of pathogenic organisms. During our previous research, we found that many bacterial enzymes involved in the biosynthesis of oligosaccharides have very flexible substrate specificities. For example, the sialic acid aldolase from E. coli K-12, which catalyzes the reversible condensation of pyruvate with D-N-acetylmannosamine (ManNAc) or D-mannose to form Neu5Ac or KDN, can tolerate the modifications on C-2, C-4, C-5 and/or C-6 hydroxyl groups of Man(NAc). Here we report that disaccharides containing a sialic acid reidue at the reducing terminus can be synthesized using sialic acid aldolase-catalyzed reaction from disaccharides having a mannose or a ManNAc at the reducing end. We have chemically synthesized Galα1,5Man, Galβ1,2Man, Galβ1,5Man, Galβ1,6Man and confirmed that they can be successfully transformed into the corresponsing Galα1,8KDN, Galβ1,5KDN, Galβ1,8KDN and Galβ1,9KDN respectively using the aldolase. |
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Chemical Glycobiology Symposium
7:00 PM-9:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Carbohydrate Chemistry |