Structural basis for specific inhibition of the highly sensitive ShHTL7 receptor
AuthorsShahul Hameed, Umar
Kountche, Boubacar Amadou
Zarban, Randa Alhassan Yahya
Arold, Stefan T.
KAUST DepartmentBiological and Environmental Science and Engineering (BESE) Division
Center for Desert Agriculture
Computational Bioscience Research Center (CBRC)
Computer, Electrical and Mathematical Science and Engineering (CEMSE) Division
Structural Biology and Engineering
Online Publication Date2018-07-18
Print Publication Date2018-09
Permanent link to this recordhttp://hdl.handle.net/10754/630755
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AbstractStriga hermonthica is a root parasitic plant that infests cereals, decimating yields, particularly in sub-Saharan Africa. For germination, Striga seeds require host-released strigolactones that are perceived by the family of HYPOSENSITIVE to LIGHT (ShHTL) receptors. Inhibiting seed germination would thus be a promising approach for combating Striga However, there are currently no strigolactone antagonists that specifically block ShHTLs and do not bind to DWARF14, the homologous strigolactone receptor of the host. Here, we show that the octyl phenol ethoxylate Triton X-100 inhibits S. hermonthica seed germination without affecting host plants. High-resolution X-ray structures reveal that Triton X-100 specifically plugs the catalytic pocket of ShHTL7. ShHTL7-specific inhibition by Triton X-100 demonstrates the dominant role of this particular ShHTL receptor for Striga germination. Our structural analysis provides a rationale for the broad specificity and high sensitivity of ShHTL7, and reveals that strigolactones trigger structural changes in ShHTL7 that are required for downstream signaling. Our findings identify Triton and the related 2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]acetic acid as promising lead compounds for the rational design of efficient Striga-specific herbicides.
CitationShahul Hameed U, Haider I, Jamil M, Kountche BA, Guo X, et al. (2018) Structural basis for specific inhibition of the highly sensitive ShHTL7 receptor. EMBO reports 19: e45619. Available: http://dx.doi.org/10.15252/embr.201745619.
SponsorsWe acknowledge SOLEIL for provision of synchrotron radiation facilities, and we would like to thank L. Chavas, P. Legrand, S. Sirigu, and P. Montaville for assistance in using beamline PROXIMA 1; G. Fox, M. Savko, and B. Shepard for assistance in using beamline PROXIMA 2A; and J. Perez and A. Thureau for assistance in using the beamline SWING. We thank the KAUST Bioscience Core Labs for their support, and we thank L. Jaremko for help with the NMR analysis. This research was supported by the Bill & Melinda Gates Foundation (OPP1136424); and the King Abdullah University of Science and Technology (KAUST).
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