A different conformation for EGC stator subcomplex in solution and in the assembled yeast V-ATPase: possible implications for regulatory disassembly.
Vacuolar ATPases (V-ATPases) are ATP-dependent proton pumps that maintain the acidity of cellular compartments. They are composed of a membrane-integrated proton-translocating V(0) and an extrinsic cytoplasmic catalytic domain V(1), joined by several connecting subunits. To clarify the arrangement of these peripheral connections and their interrelation with other subunits of the holocomplex, we have determined the solution structures of isolated EG and EGC connecting subcomplexes by small angle X-ray scattering and the 3D map of the yeast V-ATPase by electron microscopy. In solution, EG forms a slightly kinked rod, which assembles with subunit C into an L-shaped structure. This model is supported by the microscopy data, which show three copies of EG with two of these linked by subunit C. However, the relative arrangement of the EG and C subunits in solution is more open than that in the holoenzyme, suggesting a conformational change of EGC during regulatory assembly and disassembly.
Diepholz
Meikel
M
EMBL, Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Venzke
David
D
Prinz
Simone
S
Batisse
Claire
C
Flörchinger
Beate
B
Rössle
Manfred
M
Svergun
Dmitri I
DI
Böttcher
Bettina
B
Féthière
James
J
D007091:Image Processing, Computer-Assisted; D008027:Light; D008958:Models, Molecular; D008968:Molecular Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D012542:Scattering, Radiation; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D013329:Structure-Activity Relationship; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D014961:X-Ray Diffraction
D021122:Protein Subunits; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D012996:Solutions; D025262:Vacuolar Proton-Translocating ATPases