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The structure of the UDP-Glc/GlcNAc 4-epimerase from the human pathogen Campylobacter jejuni

Yun, Hyun Gi and Jang, Kyoung-Soon and Tanaka, Shiho and Clemons, William M., Jr. (2020) The structure of the UDP-Glc/GlcNAc 4-epimerase from the human pathogen Campylobacter jejuni. . (Unpublished)

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Worldwide, the food-born pathogen Campylobacter jejuni is the leading bacterial source of human gastroenteritis. C. jejuni produces a variety of diverse cell-surface carbohydrates that are essential for pathogenicity. A critical component of these oligo- and polysaccharides is the sugar N-acetylgalactosamine (GalNAc). The sole source of this sugar is the epimerization of UDP-N-acetylglucosamine (GlcNAc), a reaction catalyzed by the enzyme UDP-GlcNAc 4-epimerase (Gne). This enzyme is unique among known bacterial epimerases in that it also catalyzes the equivalent reaction with the non-N-acetylated sugars. Understanding how CjGne catalyzes these various interconversions is critical to designing novel inhibitors of this enzyme. Here, to further the mechanistic understanding we present a 2.0Å structure of CjGne with its NAD⁺ co-factor bound. Based on novel features found in the structure we perform a variety of biochemical studies to probe the mechanism and compare these results to another bifunctional epimerase, human GalE. We further show that ebselen, previously identified for inhibition of HsGalE, is active against CjGne, suggesting a route for antibiotic development.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Item2016 Annual Meeting of the Society-for-Glycobiology - Abstract
Yun, Hyun Gi0000-0002-3508-5791
Clemons, William M., Jr.0000-0002-0021-889X
Alternate Title:Crystal structure of a bifunctional CjGne
Additional Information:The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license. This version posted September 22, 2020. We thank Hazel Holden (Wisconsin) for expression plasmids for HsGalE. We are grateful to Nathan Dalleska (Caltech) for assistance with the capillary electrophoresis at the Environmental Analysis Center and Jens Kaiser and Pavle Nikolovski (Caltech) for crystallography help through the Molecular Observatory. This work was supported by grants from the National Institutes of Health (NIH) National Institute of General Medicine (NIGMS) awards GM105385 and GM114611 (to WMC). This research was undertaken in part using the 12-2 beamline at the Stanford Synchrotron Radiation Lightsource (SSRL). Operations at SSRL are supported by the US Department of Energy and the National Institutes of Health (NIH). The authors declare no conflicts of interest in regards to this manuscript.
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
Subject Keywords:Campylobacter jejuni, UDP-hexose 4-epimerase, N-linked glycan, crystal structure, NAD+, enzyme mechanism, enzyme inhibitor, protein stability, pathogenesis, glycobiology
Record Number:CaltechAUTHORS:20200925-144507331
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Official Citation:The structure of the UDP-Glc/GlcNAc 4-epimerase from the human pathogen Campylobacter jejuni. Hyun Gi Yun, Kyoung-Soon Jang, Shiho Tanaka, William M. Clemons Jr. bioRxiv 2020.09.22.308395; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105575
Deposited By: Tony Diaz
Deposited On:25 Sep 2020 22:02
Last Modified:16 Nov 2021 18:44

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