Comprehensive Summary The strategy of removable glycosylation modification was used to overcome the low-efficiency problem encountered in the chemical synthesis of the mirror-image D-version of the immunoglobulin(Ig)-...Comprehensive Summary The strategy of removable glycosylation modification was used to overcome the low-efficiency problem encountered in the chemical synthesis of the mirror-image D-version of the immunoglobulin(Ig)-like domain of tropomyosin receptor kinase A(DlgCTrkA),a protein molecule needed for mirror-image screening of D-peptide ligands targeting this cell membrane receptor.It was found that O-linked-β-N-acetyl-D-glucosamine(O-GlcNAc)modification at^(D)Ser^(312),or^(D)Ser^(320)can significantly improve the efficiency of DlgCTrkA synthesis and folding,while O-GlcNAc modification at^(D)Ser^(330)showed barely any improvement.This study provides a new example demonstrating the power of the removable glycosylation modification strategy in the chemical synthesis and folding of difficult-to-obtain proteins.It also presents evidence that removable glycosylation modification at different sites would significantly affect the efficiency of protein folding promoted by this strategy.展开更多
Glycosylation,a prevalent post-translational modification in eukaryotic secreted and membraneassociated proteins,plays a pivotal role in diverse physiological and pathological processes.Although UDP-N-acetylglucosamin...Glycosylation,a prevalent post-translational modification in eukaryotic secreted and membraneassociated proteins,plays a pivotal role in diverse physiological and pathological processes.Although UDP-N-acetylglucosamine(UDP-Glc NAc)is essential for this modification,the specific glycosylation mechanisms during plant leaf senescence and defense responses remain poorly understood.In our research,we identified a novel rice mutant named rbb1(resistance to blast and bacterial blight1),exhibiting broad-spectrum disease resistance.This mutant phenotype results from a loss-of-function mutation in the gene encoding glucosamine-6-phosphate acetyl-transferase,an important enzyme in D-glucosamine6-phosphate acetylation.The rbb1 mutant demonstrates enhanced defense responses,evident in increased resistance to rice blast and bacterial blight,along with the upregulation of defense-response genes.Various biochemical markers indicate an activated defense mechanism in the rbb1 mutant,such as elevated levels of reactive oxygen species and malondialdehyde,reduced enzyme activity and UDPGlc NAc content,and decreased expression of Nglycan and O-glycan modifying proteins.Moreover,proteome analysis of N-glycosylation modifications reveals alterations in the N-glycosylation of several disease-resistance-related proteins,with a significant reduction in Prx4 and Prx13 in rbb1-1.Additionally,the knockout of Prx4 or Prx13 also enhances resistance to Xanthomonas oryzae pv.oryzae(Xoo)and Magnaporthe oryzae(M.oryzae).This study uncovers a novel mechanism of defense response in rice,suggesting potential targets for the development of disease-resistant varieties.展开更多
The management of acute ischemic stroke remains challenging due to its abrupt onset and the narrow treatment window,resulting in high rates of disability and mortality.Combination therapy for neuroprotection and neuro...The management of acute ischemic stroke remains challenging due to its abrupt onset and the narrow treatment window,resulting in high rates of disability and mortality.Combination therapy for neuroprotection and neurorepair strategies provided new hopes for subacute stroke treatment.Here we designed a multistage nanodelivery system that matches the unique microenvironment of the subacute phase of stroke,which utilizes calixarene as a building block to effectively load the neuroprotective drug simvastatin.The calixarene is designed with glycosidic linkages targeting the glucose transporter 1(GLUT1)on the blood-brain barrier(BBB)and azo bonds that are responsive to hypoxic conditions.Additionally,the decomposed calixarene molecules themselves possess intrinsic bio-activation to modulate inflammatory responses,achieving a multistage therapeutic approach that transitions from targeting to release and finally to treatment.This approach combines anti-inflammation and neuroprotection,providing a multi-level treatment strategy.This system was validated in a rat model of permanent middle cerebral artery occlusion(p MCAO),demonstrating that intravenous administration of the nanodelivery system repairs brain damage and improves motor function 24 h post-p MCAO induction.This work offers a precise and integrative strategy for stroke patients missing the acute therapy window to improve functional recovery and enhance the effect of comprehensive treatment.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22227810,22277020,22307061)China Postdoctoral Science Foundation(No.2022M721801)the Beijing Life Science Academy(No.2023000cc0130).
文摘Comprehensive Summary The strategy of removable glycosylation modification was used to overcome the low-efficiency problem encountered in the chemical synthesis of the mirror-image D-version of the immunoglobulin(Ig)-like domain of tropomyosin receptor kinase A(DlgCTrkA),a protein molecule needed for mirror-image screening of D-peptide ligands targeting this cell membrane receptor.It was found that O-linked-β-N-acetyl-D-glucosamine(O-GlcNAc)modification at^(D)Ser^(312),or^(D)Ser^(320)can significantly improve the efficiency of DlgCTrkA synthesis and folding,while O-GlcNAc modification at^(D)Ser^(330)showed barely any improvement.This study provides a new example demonstrating the power of the removable glycosylation modification strategy in the chemical synthesis and folding of difficult-to-obtain proteins.It also presents evidence that removable glycosylation modification at different sites would significantly affect the efficiency of protein folding promoted by this strategy.
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD04073)the Guangdong Basic and Applied Basic Research Foundation(2021A1515111123,2023A1515110409)+1 种基金the China Postdoctoral Science Foundation(2020M683000)the National Natural Science Foundation of China(32201788)。
文摘Glycosylation,a prevalent post-translational modification in eukaryotic secreted and membraneassociated proteins,plays a pivotal role in diverse physiological and pathological processes.Although UDP-N-acetylglucosamine(UDP-Glc NAc)is essential for this modification,the specific glycosylation mechanisms during plant leaf senescence and defense responses remain poorly understood.In our research,we identified a novel rice mutant named rbb1(resistance to blast and bacterial blight1),exhibiting broad-spectrum disease resistance.This mutant phenotype results from a loss-of-function mutation in the gene encoding glucosamine-6-phosphate acetyl-transferase,an important enzyme in D-glucosamine6-phosphate acetylation.The rbb1 mutant demonstrates enhanced defense responses,evident in increased resistance to rice blast and bacterial blight,along with the upregulation of defense-response genes.Various biochemical markers indicate an activated defense mechanism in the rbb1 mutant,such as elevated levels of reactive oxygen species and malondialdehyde,reduced enzyme activity and UDPGlc NAc content,and decreased expression of Nglycan and O-glycan modifying proteins.Moreover,proteome analysis of N-glycosylation modifications reveals alterations in the N-glycosylation of several disease-resistance-related proteins,with a significant reduction in Prx4 and Prx13 in rbb1-1.Additionally,the knockout of Prx4 or Prx13 also enhances resistance to Xanthomonas oryzae pv.oryzae(Xoo)and Magnaporthe oryzae(M.oryzae).This study uncovers a novel mechanism of defense response in rice,suggesting potential targets for the development of disease-resistant varieties.
基金supported by the National Natural Science Foundation of China(82241058,U20A20259)the Program of Tianjin Municipal Science and Technology(21JCZDJC00290)+4 种基金the Natural Science Foundation of Tianjin of China(22JCYBJC00980)the Fundamental Research Funds for the Central Universitiesthe Natural Science Foundation of Hebei Province(B2020201092,B2023201108,2567635H)the Foundation of Hebei Education Department(JZX2024018)the Advanced Talents Incubation Program of Hebei University(521100223250)。
文摘The management of acute ischemic stroke remains challenging due to its abrupt onset and the narrow treatment window,resulting in high rates of disability and mortality.Combination therapy for neuroprotection and neurorepair strategies provided new hopes for subacute stroke treatment.Here we designed a multistage nanodelivery system that matches the unique microenvironment of the subacute phase of stroke,which utilizes calixarene as a building block to effectively load the neuroprotective drug simvastatin.The calixarene is designed with glycosidic linkages targeting the glucose transporter 1(GLUT1)on the blood-brain barrier(BBB)and azo bonds that are responsive to hypoxic conditions.Additionally,the decomposed calixarene molecules themselves possess intrinsic bio-activation to modulate inflammatory responses,achieving a multistage therapeutic approach that transitions from targeting to release and finally to treatment.This approach combines anti-inflammation and neuroprotection,providing a multi-level treatment strategy.This system was validated in a rat model of permanent middle cerebral artery occlusion(p MCAO),demonstrating that intravenous administration of the nanodelivery system repairs brain damage and improves motor function 24 h post-p MCAO induction.This work offers a precise and integrative strategy for stroke patients missing the acute therapy window to improve functional recovery and enhance the effect of comprehensive treatment.
