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PDBsum entry 4m9c
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References listed in PDB file
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Key reference
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Title
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Biochemical analysis and structure determination of bacterial acetyltransferases responsible for the biosynthesis of udp-N,N'-Diacetylbacillosamine.
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Authors
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M.J.Morrison,
B.Imperiali.
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Ref.
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J Biol Chem, 2013,
288,
32248-32260.
[DOI no: ]
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PubMed id
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Abstract
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UDP-N,N'-diacetylbacillosamine (UDP-diNAcBac) is a unique carbohydrate produced
by a number of bacterial species and has been implicated in pathogenesis. The
terminal step in the formation of this important bacterial sugar is catalyzed by
an acetyl-CoA (AcCoA)-dependent acetyltransferase in both N- and O-linked
protein glycosylation pathways. This bacterial acetyltransferase is a member of
the left-handed β-helix family and forms a homotrimer as the functional unit.
Whereas previous endeavors have focused on the Campylobacter jejuni
acetyltransferase (PglD) from the N-linked glycosylation pathway, structural
characterization of the homologous enzymes in the O-linked glycosylation
pathways is lacking. Herein, we present the apo-crystal structures of the
acetyltransferase domain (ATD) from the bifunctional enzyme PglB (Neisseria
gonorrhoeae) and the full-length acetyltransferase WeeI (Acinetobacter
baumannii). Additionally, a PglB-ATD structure was solved in complex with AcCoA.
Surprisingly, this structure reveals a contrasting binding mechanism for this
substrate when compared with the AcCoA-bound PglD structure. A comparison
between these findings and the previously solved PglD crystal structures
illustrates a dichotomy among N- and O-linked glycosylation pathway enzymes.
Based upon these structures, key residues in the UDP-4-amino and AcCoA binding
pockets were mutated to determine their effect on binding and catalysis in PglD,
PglB-ATD, and WeeI. Last, a phylogenetic analysis of the aforementioned
acetyltransferases was employed to illuminate the diversity among N- and
O-linked glycosylation pathway enzymes.
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