Biochemical Characterization of the O-Linked Glycosylation Pathway in Neisseria gonorrhoeae Responsible for Biosynthesis of Protein Glycans Containing N,N '-Diacetylbacillosamine
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Author(s)
Hartley, Meredith D.
Morrison, Michael James
Imperiali, Barbara
Aas, Finn Erik
Børud, Bente
Koomey, Michael
Date Issued
June 2011
Journal
Biochemistry
Publisher
American Chemical Society (ACS)
Citation
Hartley, Meredith D. et al. “Biochemical Characterization of the O-Linked Glycosylation Pathway in Neisseria gonorrhoeae Responsible for Biosynthesis of Protein Glycans Containing N,N′-Diacetylbacillosamine.” Biochemistry 50.22 (2011): 4936–4948.
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Author's final manuscript
Abstract
The O-linked protein glycosylation pathway in Neisseria gonorrhoeae is responsible for the synthesis of a complex oligosaccharide on undecaprenyl diphosphate and subsequent en bloc transfer of the glycan to serine residues of select periplasmic proteins. Protein glycosylation (pgl) genes have been annotated on the basis of bioinformatics and top-down mass spectrometry analysis of protein modifications in pgl-null strains [Aas, F. E., et al. (2007) Mol. Microbiol. 65, 607–624; Vik, A., et al. (2009) Proc. Natl. Acad. Sci. U.S.A. 106, 4447–4452], but relatively little biochemical analysis has been performed to date. In this report, we present the expression, purification, and functional characterization of seven Pgl enzymes. Specifically, the enzymes studied are responsible for synthesis of an uncommon uridine diphosphate (UDP)-sugar (PglD, PglC, and PglB-acetyltransferase domain), glycan assembly (PglB-phospho-glycosyltransferase domain, PglA, PglE, and PglH), and final oligosaccharide transfer (PglO). UDP-2,4-diacetamido-2,4,6-trideoxy-α-d-hexose (DATDH), which is the first sugar in glycan biosynthesis, was produced enzymatically, and the stereochemistry was assigned as uridine diphosphate N′-diacetylbacillosamine (UDP-diNAcBac) by nuclear magnetic resonance characterization. In addition, the substrate specificities of the phospho-glycosyltransferase, glycosyltransferases, and oligosaccharyltransferase (OTase) were analyzed in vitro, and in most cases, these enzymes exhibited strong preferences for the native substrates relative to closely related glycans. In particular, PglO, the O-linked OTase, and PglB(Cj), the N-linked OTase from Campylobacter jejuni, preferred the native N. gonorrhoeae and C. jejuni substrates, respectively. This study represents the first comprehensive biochemical characterization of this important O-linked glycosylation pathway and provides the basis for further investigations of these enzymes as antibacterial targets.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.1021/bi2003372
