The free-radical-based selective desulfurization of cysteine residue is an efficient protocol to achieve ligations at alanine sites in the synthesis of polypeptide and proteins. In this work, the mechanism of desulfur...The free-radical-based selective desulfurization of cysteine residue is an efficient protocol to achieve ligations at alanine sites in the synthesis of polypeptide and proteins. In this work, the mechanism of desulfurization process has been studied using the density functional theory methods. According to the calculation results, the desulfurization of the thiol group occurs via a three-steps mechanism： the abstraction of hydrogen atom on the thiol group with the radical initiator VA-044 （2,2＇-azobis[2-（2-imidazolin-2-yl）propane]dihydrochloride）, the removal of S atom under the reductant TCEP （tris（2-carboxyethyl）phosphine）, and the formation of RH molecule （with the regeneration of RS radical）. The second step （desulfurization step） is the rate-determining step, and the adduct t-BuSH facilitates the desulfurization of cysteine via benefiting the formation of the precursor of the desulfurization step.展开更多
Receptor-like kinases(RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae(Xoo) is the causal agent of...Receptor-like kinases(RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae(Xoo) is the causal agent of rice leaf blight disease. The strain PXO99 A has 18 non-TAL(transcription activation-like) effectors; however, their mechanisms of action and host target proteins remain largely unknown. Although the effector XopR from the Xoo strain MAFF311018 was shown to suppress PAMP-triggered immune responses in Arabidopsis, its target has not yet been identified. Here, we show that PXO99 A XopR interacts with BIK1 at the plasma membrane. BIK1 is a receptor-like cytoplasmic kinase(RLCK) belonging to the RLK family of proteins and mediates PAMP-triggered stomatal immunity. In turn, BIK1 phosphorylates XopR. Furthermore, XopR suppresses PAMP-triggered stomatal closure in transgenic Arabidopsis expressing XopR. In addition, XopR is able to associate with RLCKs other than BIK1. These results suggest that XopR likely suppresses plant immunity by targeting BIK1 and other RLCKs.展开更多
基金This work was supported by the National Natural Science Foundation of China （No.21202006）, the Fundamental Research Funds for the Central Universities of Ministry of Education of China （No.FRF-TP- 14-015A2）, the Natural Science Foundation of Anhui Province （No.1308085QB38）, and the Supercomputer Centre of Shanghai.
文摘The free-radical-based selective desulfurization of cysteine residue is an efficient protocol to achieve ligations at alanine sites in the synthesis of polypeptide and proteins. In this work, the mechanism of desulfurization process has been studied using the density functional theory methods. According to the calculation results, the desulfurization of the thiol group occurs via a three-steps mechanism： the abstraction of hydrogen atom on the thiol group with the radical initiator VA-044 （2,2＇-azobis[2-（2-imidazolin-2-yl）propane]dihydrochloride）, the removal of S atom under the reductant TCEP （tris（2-carboxyethyl）phosphine）, and the formation of RH molecule （with the regeneration of RS radical）. The second step （desulfurization step） is the rate-determining step, and the adduct t-BuSH facilitates the desulfurization of cysteine via benefiting the formation of the precursor of the desulfurization step.
基金supported by the National Natural Science Foundation of China(31322009)the National Basic Research Program of China(2015CB910200)the State Key Laboratory of Plant Genomics of China(SKLPG2011B0301,SKLPG2011A0301)
文摘Receptor-like kinases(RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae(Xoo) is the causal agent of rice leaf blight disease. The strain PXO99 A has 18 non-TAL(transcription activation-like) effectors; however, their mechanisms of action and host target proteins remain largely unknown. Although the effector XopR from the Xoo strain MAFF311018 was shown to suppress PAMP-triggered immune responses in Arabidopsis, its target has not yet been identified. Here, we show that PXO99 A XopR interacts with BIK1 at the plasma membrane. BIK1 is a receptor-like cytoplasmic kinase(RLCK) belonging to the RLK family of proteins and mediates PAMP-triggered stomatal immunity. In turn, BIK1 phosphorylates XopR. Furthermore, XopR suppresses PAMP-triggered stomatal closure in transgenic Arabidopsis expressing XopR. In addition, XopR is able to associate with RLCKs other than BIK1. These results suggest that XopR likely suppresses plant immunity by targeting BIK1 and other RLCKs.
