Jump to main content
Jump to site search

Issue 6, 2016
Previous Article Next Article

Analysis of transition state mimicry by tight binding aminothiazoline inhibitors provides insight into catalysis by human O-GlcNAcase

Author affiliations

Abstract

The modification of nucleocytoplasmic proteins with O-linked N-acetylglucosamine (O-GlcNAc) plays diverse roles in multicellular organisms. Inhibitors of O-GlcNAc hydrolase (OGA), the enzyme that removes O-GlcNAc from proteins, lead to increased O-GlcNAc levels in cells and are seeing widespread adoption in the field as a research tool used in cells and in vivo. Here we synthesize and study a series of tight binding carbohydrate-based inhibitors of human OGA (hOGA). The most potent of these 2′-aminothiazolines binds with a sub-nanomolar Ki value to hOGA (510 ± 50 pM) and the most selective has greater than 1 800 000-fold selectivity for hOGA over mechanistically related human lysosomal β-hexosaminidase. Structural data of inhibitors in complex with an hOGA homologue reveals the basis for variation in binding among these compounds. Using linear free energy analyses, we show binding of these 2′-aminothiazoline inhibitors depends on the pKa of the aminothiazoline ring system, revealing the protonation state of the inhibitor is a key driver of binding. Using series of inhibitors and synthetic substrates, we show that 2′-aminothiazoline inhibitors are transition state analogues of hOGA that bind to the enzyme up to 1-million fold more tightly than the substrate. These collective data support an oxazoline, rather than a protonated oxazolinium ion, intermediate being formed along the reaction pathway. Inhibitors from this series will prove generally useful tools for the study of O-GlcNAc. The new insights gained here, into the catalytic mechanism of hOGA and the fundamental drivers of potency and selectivity of OGA inhibitors, should enable tuning of hOGA inhibitors with desirable properties.

Graphical abstract: Analysis of transition state mimicry by tight binding aminothiazoline inhibitors provides insight into catalysis by human O-GlcNAcase

Back to tab navigation

Supplementary files

Publication details

The article was received on 26 Jan 2016, accepted on 12 Feb 2016 and first published on 15 Feb 2016


Article type: Edge Article
DOI: 10.1039/C6SC00370B
Author version
available:
Download author version (PDF)
Citation: Chem. Sci., 2016,7, 3742-3750
  • Open access: Creative Commons BY license
  •   Request permissions

    Analysis of transition state mimicry by tight binding aminothiazoline inhibitors provides insight into catalysis by human O-GlcNAcase

    N. Cekic, J. E. Heinonen, K. A. Stubbs, C. Roth, Y. He, A. J. Bennet, E. J. McEachern, G. J. Davies and D. J. Vocadlo, Chem. Sci., 2016, 7, 3742
    DOI: 10.1039/C6SC00370B

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements