5tec | pdb_00005tec
Crystal structure of the TIR domain from the Arabidopsis thaliana NLR protein SNC1
Structural highlights
Function[SNC1_ARATH] Disease resistance protein of the TIR-NB-LRR-type. Part of the RPP5 locus that contains a cluster of several paralogous disease resistance (R) genes. Resistance proteins guard the plant against pathogens that contain an appropriate avirulence protein via an indirect interaction with this avirulence protein. That triggers a defense system including the hypersensitive response, which restricts the pathogen growth. Regulated by RNA silencing. Expression regulated by MOS1 at chromatin level. Negatively regulated at the transcript level by BON1. Nuclear localization of SNC1 is essential for its activity (PubMed:22454454). ABA deficiency can rescue high-temperature inhibition of SNC1-mediated defense responses (PubMed:22454454).[1] [2] [3] Publication Abstract from PubMedThe Toll/interleukin-1 receptor (TIR) domain is a protein-protein interaction domain that is found in both animal and plant immune receptors. The N-terminal TIR domain from the nucleotide-binding (NB)-leucine-rich repeat (LRR) class of plant disease-resistance (R) proteins has been shown to play an important role in defence signalling. Recently, the crystal structure of the TIR domain from flax R protein L6 was determined and this structure, combined with functional studies, demonstrated that TIR-domain homodimerization is a requirement for function of the R protein L6. To advance the molecular understanding of the function of TIR domains in R-protein signalling, the protein expression, purification, crystallization and X-ray diffraction analyses of the TIR domains of the Arabidopsis thaliana R proteins RPS4 (resistance to Pseudomonas syringae 4) and RRS1 (resistance to Ralstonia solanacearum 1) and the resistance-like protein SNC1 (suppressor of npr1-1, constitutive 1) are reported here. RPS4 and RRS1 function cooperatively as a dual resistance-protein system that prevents infection by three distinct pathogens. SNC1 is implicated in resistance pathways in Arabidopsis and is believed to be involved in transcriptional regulation through its interaction with the transcriptional corepressor TPR1 (Topless-related 1). The TIR domains of all three proteins have successfully been expressed and purified as soluble proteins in Escherichia coli. Plate-like crystals of the RPS4 TIR domain were obtained using PEG 3350 as a precipitant; they diffracted X-rays to 2.05 A resolution, had the symmetry of space group P1 and analysis of the Matthews coefficient suggested that there were four molecules per asymmetric unit. Tetragonal crystals of the RRS1 TIR domain were obtained using ammonium sulfate as a precipitant; they diffracted X-rays to 1.75 A resolution, had the symmetry of space group P4(1)2(1)2 or P4(3)2(1)2 and were most likely to contain one molecule per asymmetric unit. Crystals of the SNC1 TIR domain were obtained using PEG 3350 as a precipitant; they diffracted X-rays to 2.20 A resolution and had the symmetry of space group P4(1)2(1)2 or P4(3)2(1)2, with two molecules predicted per asymmetric unit. These results provide a good foundation to advance the molecular and structural understanding of the function of the TIR domain in plant innate immunity. Crystallization and preliminary X-ray diffraction analyses of the TIR domains of three TIR-NB-LRR proteins that are involved in disease resistance in Arabidopsis thaliana.,Wan L, Zhang X, Williams SJ, Ve T, Bernoux M, Sohn KH, Jones JD, Dodds PN, Kobe B Acta Crystallogr Sect F Struct Biol Cryst Commun. 2013 Nov;69(Pt 11):1275-80., doi: 10.1107/S1744309113026614. Epub 2013 Oct 30. PMID:24192368[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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