期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 110, 期 19, 页码 7874-7879出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1303333110
关键词
F1Fo-ATP synthase rotor; membrane protein complex
资金
- Collaborative Research Center of the German Research Foundation [807]
- Cluster of Excellence Frankfurt Macromolecular Complexes at Goethe University [EXC 115]
- National Institute of General Medical Sciences [R01 GM28454]
The c-rings of ATP synthases consist of individual c-subunits, all of which harbor a conserved motif of repetitive glycine residues (GxGxGxG) important for tight transmembrane a-helix packing. The c-ring stoichiometry determines the number of ions transferred during enzyme operation and has a direct impact on the ion-to-ATP ratio, a cornerstone parameter of cell bioenergetics. In the extreme alkaliphile Bacillus pseudofirmus OF4, the glycine motif is replaced by AxAxAxA. We performed a structural study on two mutants with alanine-to-glycine changes using atomic force microscopy and X-ray crystallography, and found that mutants form smaller c(12) rings compared with the WT c(13). The molar growth yields of B. pseudofirmus OF4 cells on malate further revealed that the c(12) mutants have a considerably reduced capacity to grow on limiting malate at high pH. Our results demonstrate that the mutant ATP synthases with either c(12) or c(13) can support ATP synthesis, and also underscore the critical importance of an alanine motif with c(13) ring stoichiometry for optimal growth at pH > 10. The data indicate a direct connection between the precisely adapted ATP synthase c-ring stoichiometry and its ion-to-ATP ratio on cell physiology, and also demonstrate the bioenergetic challenges and evolutionary adaptation strategies of extremophiles.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据