24988-24-7Relevant articles and documents
Mechanistic studies of the radical S-adenosylmethionine enzyme DesII with TDP-D-fucose
Ko, Yeonjin,Ruszczycky, Mark W.,Choi, Sei-Hyun,Liu, Hung-Wen
, p. 860 - 863 (2015)
DesII is a radical S-adenosylmethionine (SAM) enzyme that catalyzes the C4-deamination of TDP-4-amino-4,6-dideoxyglucose through a C3 radical intermediate. However, if the C4 amino group is replaced with a hydroxy group (to give TDP-quinovose), the hydroxy group at C3 is oxidized to a ketone with no C4-dehydration. It is hypothesized that hyperconjugation between the C4 C-N/O bond and the partially filled p orbital at C3 of the radical intermediate modulates the degree to which elimination competes with dehydrogenation. To investigate this hypothesis, the reaction of DesII with the C4-epimer of TDP-quinovose (TDP-fucose) was examined. The reaction primarily results in the formation of TDP-6-deoxygulose and likely regeneration of TDP-fucose. The remainder of the substrate radical partitions roughly equally between C3-dehydrogenation and C4-dehydration. Thus, changing the stereochemistry at C4 permits a more balanced competition between elimination and dehydrogenation.
Target-specific identification and characterization of the putative gene cluster for brasilinolide biosynthesis revealing the mechanistic insights and combinatorial synthetic utility of 2-deoxy-l-fucose biosynthetic enzymes
Chiu, Hsien-Tai,Weng, Chien-Pao,Lin, Yu-Chin,Chen, Kuan-Hung
supporting information, p. 1988 - 2006 (2016/02/18)
Brasilinolides exhibiting potent immunosuppressive and antifungal activities with remarkably low toxicity are structurally characterized by an unusual modified 2-deoxy-l-fucose (2dF) attached to a type I polyketide (PK-I) macrolactone. From the pathogenic producer Nocardia terpenica (Nocardia brasiliensis IFM-0406), a 210 kb genomic fragment was identified by target-specific degenerate primers and subsequently sequenced, revealing a giant nbr gene cluster harboring genes (nbrCDEF) required for TDP-2dF biosynthesis and those for PK-I biosynthesis, modification and regulation. The results showed that the genetic and domain arrangements of nbr PK-I synthases agreed colinearly with the PK-I structures of brasilinolides. Subsequent heterologous expression of nbrCDEF in Escherichia coli accomplished in vitro reconstitution of TDP-2dF biosynthesis. The catalytic functions and mechanisms of NbrCDEF enzymes were further characterized by systematic mix-and-match experiments. The enzymes were revealed to display remarkable substrate and partner promiscuity, leading to the establishment of in vitro hybrid deoxysugar biosynthetic pathways throughout an in situ one-pot (iSOP) method. This study represents the first demonstration of TDP-2dF biosynthesis at the enzyme and molecular levels, and provides new hope for expanding the structural diversity of brasilinolides by combinatorial biosynthesis.
Active-site engineering of nucleotidylyltransferases and general enzymatic methods for the synthesis of natural and "unnatural" UDP- and TDP-nucleotide sugars
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, (2008/06/13)
The present invention provides mutant nucleotidylyl-transferases, such as Ep, having altered substrate specificity; methods for their production; and methods of producing nucleotide sugars, which utilize these nucleotidylyl-transferases. The present invention also provides methods of synthesizing desired nucleotide sugars using natural and/or modified Ep or other nucleotidyltransferases; and nucleotide sugars sythesized by the present methods. The present invention further provides new glycosyl phosphates, and methods for making them.
