Perosamine

Perosamine (or GDP-perosamine) is a mannose-derived 4-aminodeoxysugar produced by some bacteria.
Biological role.
"N"-acetyl-perosamine is found in the "O"-antigen of Gram-negative bacteria such as "Vibrio cholerae" "O"1, "E. coli" "O"157:H7 and "Caulobacter crescentus" CB15. The sugar is also found in perimycin, an antibiotic produced by the Gram-positive organism "Streptomyces coelicolor" var. aminophilus.
Biosynthesis.
Its biosynthesis from mannose-1-phosphate follows a pathway similar to that of colitose, but is different in that it is aminated and does not undergo 3-OH deoxygenation or C-5 epimerization.
GDP-4-keto-6-deoxymannose-4-aminotransferase (GDP-perosamine synthase).
GDP-perosamine synthase is a PLP-dependent enzyme that transfers a nitrogen from glutamate to the 4-keto position of GDP-4-keto-6-deoxymannose during the biosynthesis of GDP-perosamine.