Molecular mechanism on a germination cascade reaction of spore-forming bacteria

孢子形成细菌萌发级联反应的分子机制

• 批准号: 13660085
• 负责人: MAKINO Shio
• 金额: $ 2.24万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13660085/
• 关键词: Bacterial spores; Germination; Cortex-lytic enzymes; Activation enzyme; Cortex structure; 活性化機構

In order to elucidate bacterial germination in a molecular level, we studied the activation process of a SleC, a spore cortex-lytic enzyme of Clostridium perfringens which is synthesyzed at an early stage of sporulation as a precursor consisting of 4 domains. After cleavage of an N-terminal presequence and a C-terminal prosequence during spore maturation, inactive proenzyme is converted to active enzyme by processing of a N-terminal prosequence with germination-specific protease GSP during germination. The protease was a cysteine-dependent serine protease and it was suggested that GSP likely is localized with SleC on the exterior of the cortex layer in the dormant spore, a location relevant to the pursuit of a cascade of cortex hydrolytic reaction. SleC was most likely a bifunctional enzyme possessing lytic transglycosylase and N-acetylmuramoyl-L-alanine amidase activities. Cortex hydrolysis was performed by the cooperative action of SleC and SleM, and it was indicated that SleC causes merely small and local changes in the cortex structure, which are necessary before SleM can function. Analysis of muropeptides released during germination revealed that no muramic acid residue in the spore cortex of C. perfringens was substituted with a single L-alanine, which is a major constituent common to spore peptidoglycan of Bacillus species. These results suggest that the mechanism on spore cortex hydrolysis during germination is not conserved between Bacillus species and C. perfringens.

为了阐明在分子水平上的细菌萌发，我们研究了SleC的激活过程，SleC是产气荚膜梭菌的孢子皮层裂解酶，其在孢子形成的早期阶段合成为由4个结构域组成的前体。在孢子成熟过程中N-末端前序列和C-末端前序列裂解后，在萌发过程中通过用萌发特异性蛋白酶GSP处理N-末端前序列将无活性的酶原转化为活性酶。该蛋白酶是一种半胱氨酸依赖的丝氨酸蛋白酶，有人建议，GSP可能是本地化与SleC在休眠孢子的皮层层的外部，皮层水解反应的级联的追求相关的位置。SleC可能是一种双功能酶，具有溶解性转糖基酶和N-乙酰胞壁酰-L-丙氨酸酰胺酶活性。皮质水解是通过SleC和SleM的协同作用进行的，并且表明SleC仅引起皮质结构的小的和局部的变化，这是SleM可以起作用之前所必需的。萌发过程中释放的胞壁肽的分析表明，没有胞壁酸残留的C。产气荚膜梭菌被单个L-丙氨酸取代，所述L-丙氨酸是芽孢杆菌属物种的孢子肽聚糖共有的主要成分。这些结果表明，芽孢杆菌和C.产气荚膜杆菌

项目成果

Seiko Shimamoto: "Partial characterization of of enzyme fraction with protease activity which converts SleC precursor to active enzyme during germination"Journal of Bacteriology. 183・12. 3742-3751 (2001)

Seiko Shimamoto：“在萌发过程中将 SleC 前体转化为活性酶的具有蛋白酶活性的酶组分的部分表征”细菌学杂志 183・12 3742-3751（2001）。

Shimamoto,Seiko: "Partial characterization of enzyme fraction with protease activitywhich converts SleC precursor to active enzyme during germination"Journal of Bacteriology. 183-12. 3742-3751 (2001)

Shimamoto, Seiko：“具有蛋白酶活性的酶组分的部分表征，该酶组分在发芽过程中将 SleC 前体转化为活性酶”《细菌学杂志》。

Shio Makino: "Hydrolysis of cortex peptidoglycan during bacterial spore germination"Medicine Scientific Monitor. 8・5. 119-127 (2002)

Shio Makino：“细菌孢子萌发过程中皮质肽聚糖的水解”医学科学监测 8・5（2002）。

Seiko Shimamoto: "Partial characterization of enzyme fraction with protease activity which converts SleC precursor to active enzyme during germination"Journal of Bacteriology. 183・12. 3742-3751 (2001)

Seiko Shimamoto：“在萌发过程中将 SleC 前体转化为活性酶的具有蛋白酶活性的酶组分的部分表征”细菌学杂志 183・12 3742-3751（2001）。

Makino,Shio: "Hydrolysis of cortex peptidoglycan during bacterial spore germination"Medicine Scientific Monitor. 8-5. 119-127 (2002)

Makino，Shio：“细菌孢子萌发过程中皮质肽聚糖的水解”医学科学监测。