1. Structural Biology and Molecular Biophysics
  2. Microbiology and Infectious Disease
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A structural mechanism for bacterial autotransporter glycosylation by a dodecameric heptosyltransferase family

  1. Qing Yao
  2. Qiuhe Lu
  3. Xiaobo Wan
  4. Feng Song
  5. Yue Xu
  6. Mo Hu
  7. Alla Zamyatina
  8. Xiaoyun Liu
  9. Niu Huang
  10. Ping Zhu
  11. Feng Shao  Is a corresponding author
  1. National Institute of Biological Sciences, China
  2. Institute of Biophysics, Chinese Academy of Sciences, China
  3. Peking University, China
  4. University of Natural Resources and Life Sciences, Austria
Research Article
  • Cited 11
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Cite this article as: eLife 2014;3:e03714 doi: 10.7554/eLife.03714

Abstract

A large group of bacterial virulence autotransporters including AIDA-I from diffusely adhering E. coli (DAEC) and TibA from enterotoxigenic E. coli (ETEC) require hyper-glycosylation for functioning. Here we demonstrate that TibC from ETEC harbors a heptosyltransferase activity on TibA and AIDA-I, defining a large family of bacterial autotransporter heptosyltransferases (BAHTs). Crystal structure of TibC reveals a characteristic ring-shape dodecamer. The protomer features an N-terminal β-barrel, a catalytic domain, a β-hairpin thumb and a unique iron-finger motif. The iron-finger motif contributes to back-to-back dimerization; six dimers form the ring through β-hairpin thumb-mediated hand-in-hand contact. Structure of ADP-D, D-heptose-bound TibC reveals a sugar transfer mechanism and also the ligand stereoselectivity determinant. Cryo-EM analyses uncover a TibC-TibA dodecamer/hexamer assembly with two enzyme molecules binding to one TibA substrate. The complex structure also highlights a high efficient hyperglycosylation of six autotransporter substrates simultaneously by the dodecamer enzyme complex.

Article and author information

Author details

  1. Qing Yao

    National Institute of Biological Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  2. Qiuhe Lu

    National Institute of Biological Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  3. Xiaobo Wan

    National Institute of Biological Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  4. Feng Song

    Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  5. Yue Xu

    National Institute of Biological Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  6. Mo Hu

    Peking University, Bejing, China
    Competing interests
    No competing interests declared.
  7. Alla Zamyatina

    University of Natural Resources and Life Sciences, Vienna, Austria
    Competing interests
    No competing interests declared.
  8. Xiaoyun Liu

    Peking University, Bejing, China
    Competing interests
    No competing interests declared.
  9. Niu Huang

    National Institute of Biological Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  10. Ping Zhu

    Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
    Competing interests
    No competing interests declared.
  11. Feng Shao

    National Institute of Biological Sciences, Beijing, China
    For correspondence
    shaofeng@nibs.ac.cn
    Competing interests
    Feng Shao, Reviewing editor, eLife.

Reviewing Editor

  1. Wilfred van der Donk, University of Illinois-Urbana Champaign, United States

Publication history

  1. Received: June 17, 2014
  2. Accepted: October 12, 2014
  3. Accepted Manuscript published: October 13, 2014 (version 1)
  4. Version of Record published: November 18, 2014 (version 2)

Copyright

© 2014, Yao et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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