The acarbose-biosynthetic enzyme AcbO from Actinoplanes sp. SE 50/110 is a 2-epi-5-epi-valiolone-7-phosphate 2-epimerase.
The C7-cyclitol 2-epi-5-epi-valiolone is the first precursor of the cyclitol moiety of the alpha-glucosidase inhibitor acarbose in Actinoplanes sp. SE50. The 2-epi-5-epi-valiolone becomes phosphorylated at C7 by the ATP dependent kinase AcbM prior to the next modifications. Preliminary data gave evidences that the AcbO protein could catalyse the first modification step of 2-epi-5-epi-valiolone-7-phosphate. Therefore, the AcbO protein, the encoding gene of which is also part of the acbKMLNOC operon, was overproduced and purified. Indeed the purified protein catalysed the 2-epimerisation of 2-epi-5-epi-valiolone-7-phosphate. The chemical structure of the purified reaction product was proven by nuclear magnetic resonance spectroscopy to be 5-epi-valiolone-7-phosphate.
Zhang
Chang-Sheng
CS
Institute of Chemical Microbiology, Bergische University, Gauss-Str 20, D-42097 Wuppertal, Germany.
Podeschwa
Michael
M
Altenbach
Hans-Josef
HJ
Piepersberg
Wolfgang
W
Wehmeier
Udo F
UF
D020909:Acarbose / Q000378:metabolism*; D000192:Actinomycetales / Q000201:enzymology*; D002240:Carbohydrate Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D019998:Racemases and Epimerases / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification
D011993:Recombinant Fusion Proteins; D019998:Racemases and Epimerases; D020909:Acarbose