4mn8 | pdb_00004mn8
Crystal structure of flg22 in complex with the FLS2 and BAK1 ectodomains
Structural highlights
FunctionFLS2_ARATH Constitutes the pattern-recognition receptor (PPR) that determines the specific perception of flagellin (flg22), a potent elicitor of the defense response to pathogen-associated molecular patterns (PAMPs). Flagellin-binding to the receptor is the first step to initiate the innate immune MAP kinase signaling cascade (MEKK1, MKK4/MKK5 and MPK3/MPK6), resulting in enhanced resistance against pathogens. Binding to the effector AvrPto1 from Pseudomonas syringae blocks the downstream plant immune response.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedFlagellin perception in Arabidopsis is through recognition of its highly conserved N-terminal epitope (flg22) by flagellin-sensitive 2 (FLS2). Flg22 binding induces FLS2 heteromerization with BRASSINOSTEROID INSENSITIVE 1-associated kinase 1 (BAK1) and their reciprocal activation followed by plant immunity. Here, we report the crystal structure of FLS2 and BAK1 ectodomains complexed with flg22 at 3.06 angstroms. A conserved and a nonconserved site from the inner surface of the FLS2 solenoid recognize the C- and N-terminal segment of flg22, respectively, without oligomerization or conformational changes in the FLS2 ectodomain. Besides directly interacting with FLS2, BAK1 acts as a co-receptor by recognizing the C terminus of the FLS2-bound flg22. Our data reveal the molecular mechanisms underlying FLS2-BAK1 complex recognition of flg22 and provide insight into the immune receptor complex activation. Structural basis for flg22-induced activation of the Arabidopsis FLS2-BAK1 immune complex.,Sun Y, Li L, Macho AP, Han Z, Hu Z, Zipfel C, Zhou JM, Chai J Science. 2013 Nov 1;342(6158):624-8. doi: 10.1126/science.1243825. Epub 2013 Oct , 10. PMID:24114786[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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