Non-specific activities of the major herbicide-resistance gene BAR
Name
Christ_NaturePlants_2017.pdf
Size
1.67 MB
Format
Adobe PDF
Checksum (MD5)
baf2a5617e88a6ff04ad2dea26bdbcd7
Author(s)
Christ, Bastien
Hochstrasser, Ramon
Guyer, Luzia
Francisco, Rita
Aubry, Sylvain
Hörtensteiner, Stefan
Weng, Jing-Ke
Date Issued
November 2017
Journal
Nature Plants
Publisher
Springer Nature
Citation
Christ, Bastien, et al. “Non-Specific Activities of the Major Herbicide-Resistance Gene BAR.” Nature Plants, vol. 3, no. 12, Dec. 2017, pp. 937–45. © 2017 The Authors
Version
Author's final manuscript
Abstract
Bialaphos resistance (BAR) and phosphinothricin acetyltransferase (PAT) genes, which convey resistance to the broad-spectrum herbicide phosphinothricin (also known as glufosinate) via N-acetylation, have been globally used in basic plant research and genetically engineered crops1-4. Although early in vitro enzyme assays showed that recombinant BAR and PAT exhibit substrate preference toward phosphinothricin over the 20 proteinogenic amino acids1, indirect effects of BAR-containing transgenes in planta, including modified amino acid levels, have been seen but without the identification of their direct causes5,6. Combining metabolomics, plant genetics and biochemical approaches, we show that transgenic BAR indeed converts two plant endogenous amino acids, aminoadipate and tryptophan, to their respective N-acetylated products in several plant species. We report the crystal structures of BAR, and further delineate structural basis for its substrate selectivity and catalytic mechanism. Through structure-guided protein engineering, we generated several BAR variants that display significantly reduced non-specific activities compared with its wild-type counterpart in vivo. The transgenic expression of enzymes can result in unintended off-target metabolism arising from enzyme promiscuity. Understanding such phenomena at the mechanistic level can facilitate the design of maximally insulated systems featuring heterologously expressed enzymes.
MIT Department
Whitehead Institute for Biomedical Research
Massachusetts Institute of Technology. Department of Biology
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/S41477-017-0061-1
