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Dimer formation of subunit G of the yeast V‐ATPase
Author(s) -
Armbrüster Andrea,
Bailer Susanne M,
Koch Michel H.J,
Godovac-Zimmermann Jasminka,
Grüber Gerhard
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)00643-4
Subject(s) - protein subunit , dimer , radius of gyration , molecular mass , size exclusion chromatography , stokes radius , monomer , chemistry , polyacrylamide gel electrophoresis , crystallography , atpase , gel electrophoresis , enzyme , yeast , escherichia coli , biochemistry , polymer , gene , organic chemistry
The G subunit of the vacuolar ATPase (V‐ATPase) is a component of the stalk connecting the V 1 and V O sectors of the enzyme and is essential for normal assembly and function. Subunit G (Vma10p) of the yeast V‐ATPase was expressed in Escherichia coli as a soluble protein and was purified to homogeneity. The molecular mass of subunit G, determined by Native‐polyacrylamide gel electrophoresis, gel filtration analysis and small‐angle X‐ray scattering, was approximately 28±2 kDa, indicating that this protein is dimeric. With a radius of gyration ( R g ) and a maximum size ( D max ) of 2.7±0.2 nm and 8.0±0.3 nm, respectively, the G‐dimer is rather elongated. To understand which region of subunit G is required to mediate dimerization, a G 38–144 form (the carboxyl‐terminus) was expressed and purified. G 38–144 is homogeneous, with a molecular mass of approximately 12±3 kDa, indicating a monomeric form in solution.