Background: CMP-pseudaminic acid formation and role in Bacillus thuringiensis flagellin glycosylation are unknown. Results: Seven enzymes are required to convert UDP-N-acetylglucosamine to CMP-pseudaminic acid; UDP-N-acetylglucosamine is converted to UDP-6-deoxy-D-N-acetylglucosamine-5,6-ene and then to UDP-4-keto-6-deoxy-L-N-acetylaltrosamine. Conclusion: Two previously undescribed enzymes initiate the CMP-pseudaminic acid pathway. Significance: Identifying a unique CMP-pseudaminic acid pathway in a Gram-positive bacterium may provide new opportunities to control bacterial flagellin glycosylation and pathogenicity.

Background: Activated sugars required to form rare oligosaccharide subunits of Bacillus cereus biofilm-polysaccharide are not known. Results: A new nucleotide sugar, UDP-fucosamine-4N-(2)-oxoglutarate (UDP-Yelosamine), is formed from UDP-4-keto-6-deoxy-D-GlcNAc by an aminotransferase and a carboxylate-amine ligase. Conclusion: Both enzymes are promiscuous and convert other UDP-4-keto amino-sugars to their UDP-4-amino-2-oxoglutarate derivatives. Significance: New insights into metabolic routes involved in the synthesis of bacterial biofilm polysaccharide have been uncovered.