蛋白质分泌区在过度表达的氨酶在格拉姆阳性细胞壁内的蛋白质分泌区
Manuel Strach1, Felicitas Koch1, Svenja Fiedler1
1Centre for Synthetic Microbiology (SYNMIKRO) and Fachbereich Chemie, Philipps-Universität Marburg, Marburg, 35032, Germany.
BMC biology
|October 4, 2023
概括
研究人员研究了格拉姆阳性细菌中的蛋白质分泌,发现像α-amylase (AmyE) 这样的蛋白质通过活性运输通过细胞膜移动,然后在Bacillus菌株中缓慢通过细胞壁扩散.
科学领域:
- 微生物学 微生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 蛋白质穿过细胞膜的转移是众所周知的,但Gram阳性细菌穿越细胞壁的机制仍然不清楚.
- 包括Bacillus subtilis和Bacillus licheniformis在内的阳性细菌在工业应用中至关重要,使它们的蛋白质分泌途径显著.
- 了解这些途径是优化涉及这些微生物的生物技术过程的关键.
研究的目的:
- 阐明蛋白质,特别是α-amylase (AmyE) 通过细胞壁分泌的机制,在格拉姆阳性细菌.
- 研究AmyE分泌的动态和局部以及SecA和SecDF等相关蛋白质.
- 为了确定细菌菌株中的蛋白质分泌是否涉及通过细胞壁的活性或被动运输机制.
主要方法:
- 使用光记者融合 (AmyE-mCherry) 来实时可视化蛋白质分泌.
- 采用单个粒子跟踪和同定位研究来分析AmyE,Seca和SecDF的动态.
- 在高复制量等离子体表达条件下以及在不同的生长阶段 (过渡到静止阶段) 期间,研究了蛋白质分泌.
主要成果:
- 在细胞壁中确定了离散的"分泌区",其中AmyE通过低动态补丁分泌,表明活性酶释放.
- 观察到分泌区和SecA信号之间的重叠,但与分泌ATPase的同定位不一致,这表明多步骤的过程.
- 与AmyE相比,单颗粒跟踪揭示了SecA和SecDF在细胞膜中的更高动态,支持初始的膜转位,随后是缓慢的细胞壁穿越.
结论:
- 细菌中的蛋白质分泌涉及通过细胞膜的活跃转移,随后通过细胞壁的更慢,可能基于扩散的过渡.
- 在过渡到静止阶段和静止阶段内观察到分泌区,支持细胞壁通道的扩散模型,特别是过度表达的蛋白质.
- 这些发现表明了巴西路斯中分泌蛋白质运输的一般模型,突出了膜和细胞壁交叉的独特机制.
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