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The structural bases for agonist diversity in an Arabidopsis thaliana glutamate receptor-like channel.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2020 Jan 07; Vol. 117 (1), pp. 752-760. Date of Electronic Publication: 2019 Dec 23. - Publication Year :
- 2020
-
Abstract
- Arabidopsis thaliana glutamate receptor-like (GLR) channels are amino acid-gated ion channels involved in physiological processes including wound signaling, stomatal regulation, and pollen tube growth. Here, fluorescence microscopy and genetics were used to confirm the central role of GLR3.3 in the amino acid-elicited cytosolic Ca <superscript>2+</superscript> increase in Arabidopsis seedling roots. To elucidate the binding properties of the receptor, we biochemically reconstituted the GLR3.3 ligand-binding domain (LBD) and analyzed its selectivity profile; our binding experiments revealed the LBD preference for l-Glu but also for sulfur-containing amino acids. Furthermore, we solved the crystal structures of the GLR3.3 LBD in complex with 4 different amino acid ligands, providing a rationale for how the LBD binding site evolved to accommodate diverse amino acids, thus laying the grounds for rational mutagenesis. Last, we inspected the structures of LBDs from nonplant species and generated homology models for other GLR isoforms. Our results establish that GLR3.3 is a receptor endowed with a unique amino acid ligand profile and provide a structural framework for engineering this and other GLR isoforms to investigate their physiology.<br />Competing Interests: The authors declare no competing interest.
- Subjects :
- Arabidopsis genetics
Arabidopsis Proteins agonists
Arabidopsis Proteins genetics
Arabidopsis Proteins metabolism
Binding Sites genetics
Calcium metabolism
Crystallography, X-Ray
Cytosol metabolism
Ligands
Mutation
Plant Roots metabolism
Plants, Genetically Modified
Receptors, Glutamate genetics
Receptors, Glutamate metabolism
Seedlings metabolism
Structure-Activity Relationship
Amino Acids metabolism
Arabidopsis metabolism
Arabidopsis Proteins ultrastructure
Protein Domains genetics
Receptors, Glutamate ultrastructure
Subjects
Details
- Language :
- English
- ISSN :
- 1091-6490
- Volume :
- 117
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 31871183
- Full Text :
- https://doi.org/10.1073/pnas.1905142117