Glucosamine, biosynthesis

There has been one report on the biosynthesis of FR900482 [114]. Radiolabeled D-glucosamine 33 and AHBA 38 were efficiently incorporated into 6, and D-[l-13C]-glucosamine was incorporated in the expected orientation (Figure 11.10). The biosynthetic gene cluster for FR900482 has been isolated from Streptomyces sandaensis and indicates a strong biosynthetic relationship with mitomycin C (Y. Mao, D. H. Sherman, unpublished results). 

Figure 48-9. Structure of heparin. The polymer section illustrates structural features typical of heparin however, the sequence of variously substituted repeating disaccharide units has been arbitrarily selected. In addition, non-O-sulfated or 3-0-sulfated glucosamine residues may also occur. (Modified, redrawn, and reproduced, with permission, from Lindahl U et al Structure and biosynthesis of heparin-like polysaccharides. Fed Proc 1977 36 19.)...

Cifonelli The Biosynthesis of Hyaluronic Acid by Group A Streptococcus. IV. Role of Glucosone as an Intermediate in the Synthesis of Glucosamine. J. biol. Chemistry 216, 549 (1955)-... 

Not much has been added to the biochemistry of STRs in the recent years. Therefore, we will only briefly treat the biosynthetic pathway here. Biosynthesis of the aminocyclitol (streptidine) and 6-deoxyhexose (streptose) moieties are well understood, with some remaining gaps in the enzymology. Much less is known about the residual biosynthetic phases, the formation of A-methyl-L-glucosamine, the condensation of subunits, and the late modification steps potentially coupled with export. ... 

We propose that the first step in NDP-kasugamine biosynthesis is 2-epimeriza-tion of the postulated UDP-A -acetyl-D-glucosamine precursor, which is suggested by the similarity of the KasQ protein with known UDP-(Af-acetyl-)D-glucosamine 2-epimerases and catalyzes the conversion to UDP-N-acetyl-D-mannosamine. To... 

Defects in the early steps of LLO biosynthesis (Fig. 4.5.1) lead to an accumulation of shortened LLO that escape the extraction procedure described above (e.g. CDG-Ik). Moreover, defects in the initiating steps of LLO biosynthesis, such as the addition of the two glucosamine residues and the first mannose residue, are missed by metabolic labelling with [2-3H]mannose. In this case it is necessary to label fibroblasts with [6-3H] glucosamine. 

Miller, W.L., Wenzel, C.Q., Daniels, C., Larocque, S., Brisson, J.-R., Lam, J.S. Biochemical characterization of WbpA, a UDP-N-acetyl-D-glucosamine 6-dehydrogenase involved in O-antigen biosynthesis in Pseudomonas aeruginosa PAOl. J Biol Chem 279 (2004) 37551-37558. 

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