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Three-dimensional map of a plant V-ATPase based on electron microscopy
Ines Domgall1, David Venzke, Ulrich Lüttge
1Structural and Computational Biology Programme, EMBL, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
The Journal of Biological Chemistry
|January 30, 2002
Summary
This study reveals the three-dimensional structure of the V-ATPase proton pump, detailing its stalk region connecting the V(0) and V(1) subcomplexes. Changes in stalk organization correlate with V-ATPase stability and potential disassembly.
Area of Science:
- Biochemistry
- Structural Biology
- Cell Biology
Background:
- V-ATPases are essential proton pumps crucial for cellular functions.
- These pumps consist of membrane-integrated V(0) and catalytic V(1) subcomplexes linked by a stalk.
- Previous structural data lacked detailed resolution of the stalk region.
Purpose of the Study:
- To elucidate the three-dimensional organization of the V-ATPase stalk region.
- To investigate the structural impact of ATP hydrolysis on V-ATPase conformation.
- To understand the mechanisms underlying V-ATPase stability and disassembly.
Main Methods:
- Three-dimensional reconstruction using electron microscopy.
- Analysis of the V-ATPase complex from Kalanchoë daigremontiana.
- Comparison of structures in the presence and absence of an ATP analogue.
Main Results:
- Detailed 3D maps of the complete V-ATPase at 2.2 nm resolution were generated.
- The stalk region revealed a central stalk surrounded by three peripheral stalks of varying sizes.
- Absence of ATP analogue led to altered V(0)-V(1) tilt and less defined stalk, indicating increased flexibility and potential detachment.
Conclusions:
- The study provides unprecedented structural insights into the V-ATPase stalk region.
- Conformational changes in the stalk are linked to V-ATPase stability and may initiate disassembly.
- These findings contribute to understanding the dynamic regulation of proton pumps.