Accepted name: L-evernosamine nitrososynthase
Reaction: dTDP-β-L-evernosamine + 2 NADPH + 2 H+ + 2 O2 = dTDP-2,3,6-trideoxy-3-C-methyl-4-O-methyl-3-nitroso-β-L-arabino-hexopyranose + 2 NADP+ + 3 H2O (overall reaction)
(1a) dTDP-β-L-evernosamine + NADPH + H+ + O2 = dTDP-N-hydroxy-β-L-evernosamine + NADP+ + H2O
(1b) dTDP-N-hydroxy-β-L-evernosamine + NADPH + H+ + O2 = dTDP-2,3,6-trideoxy-3-C-methyl-4-O-methyl-3-nitroso-β-L-arabino-hexopyranose + NADP+ + 2 H2O
Glossary: dTDP-β-L-evernosamine = dTDP-3-amino-2,3,6-trideoxy-3-C-methyl-4-O-methyl-β-L-arabino-hexopyranose
dTDP-β-L-evernitrose = dTDP-2,3,6-trideoxy-3-C-methyl-4-O-methyl-3-nitro-β-L-arabino-hexopyranose
Systematic name: dTDP-β-L-evernosamine,NADPH:oxygen oxidoreductase (N-hydroxylating)
Comments: Requires FAD. Isolated from the bacterium Micromonospora carbonacea var. africana. The nitroso group is probably spontaneously oxidized to a nitro group giving dTDP-β-L-evernitrose, which is involved in the biosynthesis of the antibiotic everninomycin. The reaction was studied using dTDP-β-L-4-epi-vancosamine (dTDP-4-O-desmethyl-β-L-evernitrosamine).
1.  Hu, Y., Al-Mestarihi, A., Grimes, C.L., Kahne, D. and Bachmann, B.O. A unifying nitrososynthase involved in nitrosugar biosynthesis. J. Am. Chem. Soc. 130 (2008) 15756–15757. [PMID: 18983146]
2.  Vey, J.L., Al-Mestarihi, A., Hu, Y., Funk, M.A., Bachmann, B.O. and Iverson, T.M. Structure and mechanism of ORF36, an amino sugar oxidizing enzyme in everninomicin biosynthesis. Biochemistry 49 (2010) 9306–9317. [PMID: 20866105]
[EC created 2014]
Accepted name: chloroorienticin B synthase
Reaction: dTDP-β-L-4-epi-vancosamine + desvancosaminyl-vancomycin = dTDP + chloroorienticin B
Glossary: dTDP-β-L-4-epi-vancosamine = dTDP-3-amino-2,3,6-trideoxy-3-methyl-β-L-arabino-hexopyranose
desvancosaminyl-vancomycin = vanomycin pseudoaglycone
Other name(s): GtfA
Systematic name: dTDP-L-4-epi-vancosamine:desvancosaminyl-vancomycin vancosaminyltransferase
Comments: The enzyme from the bacterium Amycolatopsis orientalis is involved in the biosynthesis of the glycopeptide antibiotic chloroeremomycin.
1.  Mulichak, A.M., Losey, H.C., Lu, W., Wawrzak, Z., Walsh, C.T. and Garavito, R.M. Structure of the TDP-epi-vancosaminyltransferase GtfA from the chloroeremomycin biosynthetic pathway. Proc. Natl. Acad. Sci. USA 100 (2003) 9238–9243. [PMID: 12874381]
2.  Lu, W., Oberthur, M., Leimkuhler, C., Tao, J., Kahne, D. and Walsh, C.T. Characterization of a regiospecific epivancosaminyl transferase GtfA and enzymatic reconstitution of the antibiotic chloroeremomycin. Proc. Natl. Acad. Sci. USA 101 (2004) 4390–4395. [PMID: 15070728]
[EC created 2013]