Mechanistic studies of the biosynthesis of 2-thiosugar: evidence for the formation of an enzyme-bound 2-ketohexose intermediate in BexX-catalyzed reaction.
The first mechanistic insight into 2-thiosugar production in an angucycline-type antibiotic, BE-7585A, is reported. d-Glucose 6-phosphate was identified as the substrate for the putative thiosugar biosynthetic protein, BexX, by trapping the covalently bonded enzyme-substrate intermediate. The site-specific modification at K110 residue was determined by mutagenesis studies and LC-MS/MS analysis. A key intermediate carrying a keto functionality was confirmed to exist in the enzyme-substrate complex. These results suggest that the sulfur insertion mechanism in 2-thiosugar biosynthesis shares similarities with that for thiamin biosynthesis.
Sasaki
Eita
E
Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, United States.
Liu
Hung-Wen
HW
D002384:Catalysis; D008401:Gas Chromatography-Mass Spectrometry; D019298:Glucose-6-Phosphate / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000737:chemistry*; D054330:Thiosugars / Q000737:chemistry*
D007659:Ketones; D011994:Recombinant Proteins; D054330:Thiosugars; D019298:Glucose-6-Phosphate