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| 丁香假单胞菌III型分泌系统组分HrpH酶学功能解析 | |
| 引用本文： | 王若娜,马毅楠,李俊州,王远宏,魏海雷.丁香假单胞菌III型分泌系统组分HrpH酶学功能解析[J].植物病理学报,2022,52(3):334-340. |
| 作者姓名： | 王若娜 马毅楠 李俊州 王远宏 魏海雷 |
| 作者单位： | 天津农学院园艺园林学院,天津 300384; 中国农业科学院农业资源与农业区划研究所,农业农村部农业微生物资源收集与保藏重点实验室,北京 100081 |
| 基金项目： | 国家自然科学基金（31871924）； |
| 摘 要： | III型分泌系统(T3SS)是植物病原细菌的主要致病系统,负责分泌和转运效应蛋白。T3SS结构的形成需要跨越由肽聚糖包被的细菌细胞壁周质层。HrpH是丁香假单胞菌T3SS特化的裂解性转糖基酶。本研究通过原核表达纯化了HrpH及其相关结构域蛋白,发现HrpH具有结合肽聚糖的能力,其中SLT结构域是肽聚糖结合的关键功能域,第148位的谷氨酸是结合的关键位点。进一步研究发现HrpH能够抑制丁香假单胞菌番茄致病变种DC3000(Pst DC3000)的生长,透射电镜显示,HrpH蛋白处理Pst DC3000使其细胞壁的完整性受损。以上研究结果表明HrpH通过裂解细胞壁、结合肽聚糖从而协助T3SS穿透细菌细胞壁形成超分子复合体。 |
| 关 键 词： | 丁香假单胞菌 III型分泌系统 裂解性转糖基酶 HrpH |
| 收稿时间： | 2021-04-06 |
Enzymatic characterization of the type III secretion system substrate HrpH in Pseu-domonas syringae |
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| WANG Ruona,MA Yinan,LI Junzhou,WANG Yuanhong,WEI Hailei.Enzymatic characterization of the type III secretion system substrate HrpH in Pseu-domonas syringae[J].Acta Phytopathologica Sinica,2022,52(3):334-340. | |
| Authors: | WANG Ruona MA Yinan LI Junzhou WANG Yuanhong WEI Hailei |
| Institution: | College of Horticulture and Landscape Architecture, Tianjin Agricultural University, Tianjin 300384,China; Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Beijing 100081,China |
| Abstract: | Pseudomonas syringae pv. tomato DC3000 is a typical plant pathogen relying on the type III secretion system (T3SS) to cause disease. T3SS needs to cross the periplasm of the bacterial cell wall coated with peptidoglycan in order to inject the effectors into plant cells. As a T3SS-specialized lytic transglycosylase, HrpH was predicted to target on the peptidoglycan layer in the bacterial cell wall, but the relationship between lytic function and translocation of effectors is still unclear. In this study, HrpH and its truncated domains were expressed and purified to determine the peptidoglycan binding activity. HrpH could bind the peptidoglycan and the SLT domain of HrpH is the key functional domain in which the glutamic acid at position 148 is essential for peptidoglycan binding. Further studies revealed that HrpH inhibited the growth of Pst DC3000. The integrity of the cell wall of Pst DC3000 was impaired being treated with HrpH protein, which could be observed under the transmission electron microscope. These results indicate that HrpH has lytic transglycosylase activity to bind the peptidoglycan, thereby assisting the establishment of the type III secretion apparatus for effector secretion and translocation. |
| Keywords: | Pseudomonas syringae type III secretion system lytic transglycosylase HrpH |
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