3hgk | pdb_00003hgk
crystal structure of effect protein AvrptoB complexed with kinase Pto
Structural highlights
Function[HPAB2_PSESM] Effector protein involved in gene-for-gene resistance in tomato plants. It is recognized by the host Pto resistance protein and elicits Pto and Prf-dependent hypersensitive response (HR) and programmed cell death (PCD), resulting in host immunity. In susceptible plants, acts as a virulence factor by suppressing PCD and HR-based plant immunity. This function requires its E3 ubiquitin ligase activity probably by recruiting E2 enzymes and transferring ubiquitin molecules to cellular proteins involved in regulation of PCD and targeting them for degradation. Also, induces expression of host genes involved in ethylene biosynthesis and signaling, in particular ACO1 and ACO2, encoding the ethylene-forming enzyme ACC oxidase.[1] [2] [3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedResistance to bacterial speck disease in tomato (Solanum lycopersicum) is activated upon recognition by the host Pto kinase of either one of two sequence-unrelated effector proteins, AvrPto or AvrPtoB, from Pseudomonas syringae pv tomato (Pst). Pto induces Pst immunity by acting in concert with the Prf protein. The recently reported structure of the AvrPto-Pto complex revealed that interaction of AvrPto with Pto appears to relieve an inhibitory effect of Pto, allowing Pto to activate Prf. Here, we present the crystal structure of the Pto binding domain of AvrPtoB (residues 121 to 205) at a resolution of 1.9A and of the AvrPtoB(121-205)-Pto complex at a resolution of 3.3 A. AvrPtoB(121-205) exhibits a tertiary fold that is completely different from that of AvrPto, and its conformation remains largely unchanged upon binding to Pto. In common with AvrPto-Pto, the AvrPtoB-Pto complex relies on two interfaces. One of these interfaces is similar in both complexes, although the primary amino acid sequences from the two effector proteins are very different. Amino acid substitutions in Pto at the other interface disrupt the interaction of AvrPtoB-Pto but not that of AvrPto-Pto. Interestingly, substitutions in Pto affecting this unique interface also cause Pto to induce Prf-dependent host cell death independently of either effector protein. Crystal structure of the complex between Pseudomonas effector AvrPtoB and the tomato Pto kinase reveals both a shared and a unique interface compared with AvrPto-Pto.,Dong J, Xiao F, Fan F, Gu L, Cang H, Martin GB, Chai J Plant Cell. 2009 Jun;21(6):1846-59. Epub 2009 Jun 9. PMID:19509331[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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