6q6z
Structure of the plant immune signaling node EDS1 (enhanced disease susceptibility 1) in complex with nanobody ENB21
Structural highlights
FunctionEDS1L_ARATH Positive regulator of basal resistance and of effector-triggered immunity specifically mediated by TIR-NB-LRR resistance proteins. Disruption by bacterial effector of EDS1-TIR-NB-LRR resistance protein interactions constitutes the first step in resistance activation (PubMed:22158819). Triggers early plant defenses and hypersensitive response independently of PAD4, and then recruits PAD4 to potentiate plant defenses through the accumulation of salicylic acid (PubMed:11574472). Nuclear localization is essential for basal and TIR-NB-LRR-conditioned immunity and for reprogramming defense gene expression, while cytoplasmic EDS1 is required to induce a complete immune response (PubMed:20617163). Heterodimerization with PAD4 or SGA101 is necessary for TNL-mediated effector-triggered immunity (PubMed:24331460). Contributes to nonhost resistance against E.amylovora (PubMed:22316300). Has no direct lipase activity (PubMed:16040633).[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedIn plant innate immunity, enhanced disease susceptibility 1 (EDS1) integrates all pathogen-induced signals transmitted by TIR-type NLR receptors. Driven by an N-terminal alpha/beta-hydrolase-folded domain with a protruding interaction helix, EDS1 assembles with two homologs, phytoalexin-deficient 4 (PAD4) and senescence-associated gene 101 (SAG101). The resulting heterodimers are critical for EDS1 function and structurally well characterized. Here, we resolve solution and crystal structures of unbound Arabidopsis thaliana EDS1 (AtEDS1) using nanobodies for crystallization. These structures, together with gel filtration and immunoprecipitation data, show that PAD4/SAG101-unbound AtEDS1 is stable as a monomer and does not form the homodimers recorded in public databases. Its PAD4/SAG101 anchoring helix is disordered unless engaged in protein/protein interactions. As in the complex with SAG101, monomeric AtEDS1 has a substrate-inaccessible esterase triad with a blocked oxyanion hole and without space for a covalent acyl intermediate. These new structures suggest that the AtEDS1 monomer represents an inactive or pre-activated ground state. Arabidopsis immunity regulator EDS1 in a PAD4/SAG101-unbound form is a monomer with an inherently inactive conformation.,Voss M, Toelzer C, Bhandari DD, Parker JE, Niefind K J Struct Biol. 2019 Sep 21. pii: S1047-8477(19)30201-1. doi:, 10.1016/j.jsb.2019.09.007. PMID:31550533[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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