一种增强蛋白质出口的膜成分SecDF的结构和功能.
Tomoya Tsukazaki1, Hiroyuki Mori, Yuka Echizen
1Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
Nature
|May 13, 2011
概括
SecDF充当膜伴侣,利用质子动力驱动ATP独立蛋白质在细菌膜上的转移. 这种蛋白质复合物促进了蛋白质的运输和膜蛋白质的生物发生.
科学领域:
- 细菌蛋白质分泌物 细菌蛋白质分泌物
- 膜蛋白的生物发生.
- 运输的分子机制.
背景情况:
- 通过细菌膜的蛋白质转位涉及SecYEG转位子和Seca ATPase.
- 质子驱动力和膜集成的SecDF复合物增强了这一过程.
- 在转位和膜蛋白生物发生过程中SecDF的确切功能仍然不完全理解.
研究的目的:
- 阐明SecDF复合体在细菌蛋白转位中的结构和功能作用.
- 研究SecDF促进蛋白质运输的机制.
- 为了确定质子动力对SecDF介导转位的贡献.
主要方法:
- 在3.3 Å分辨率下确定了Thermus thermophilus SecDF的晶体结构.
- 对SecDF的周等离子域 (P1和P4) 进行了更高分辨率的分析.
- 对SecDF.进行了体外转位试验和电生理学分析.
主要成果:
- 晶体结构揭示了一个伪对称的跨膜域 (RND超级家族) 和周等离子域P1和P4.
- 周等离子体域P1在结合未折叠的蛋白质时经历了构造变化.
- SecDF促进了需要质子驱动力的ATP独立转位步骤,并表现出依赖pH和基质存在的质子导电性.
- 通过膜接口保存的残留物对于质子和前蛋白运动至关重要.
结论:
- SecDF的功能是作为一个膜集成的伴侣.
- 质子动力驱动由SecDF.介导的ATP独立蛋白质转位机制.
- 通过质子导电和结构灵活性,SecDF在促进蛋白质运输和潜在的膜蛋白生物发生方面发挥着关键作用.
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