The oligomeric state of the plasma membrane H -ATPase from Kluyveromyces lactis Article uri icon

abstract

  • The plasma membrane H -ATPase was purified from the yeast K. lactis. The oligomeric state of the H -ATPase is not known. Size exclusion chromatography displayed two macromolecular assembly states (MASs) of different sizes for the solubilized enzyme. Blue native electrophoresis (BN-PAGE) showed the H -ATPase hexamer in both MASs as the sole/main oligomeric state—in the aggregated and free state. The hexameric state was confirmed in dodecyl maltoside-treated plasma membranes by Western-Blot. Tetramers, dimers, and monomers were present in negligible amounts, thus depicting the oligomerization pathway with the dimer as the oligomerization unit. H -ATPase kinetics was cooperative (n~1.9), and importantly, in both MASs significant differences were determined in intrinsic fluorescence intensity, nucleotide affinity and Vmax; hence suggesting the large MAS as the activated state of the H -ATPase. It is concluded that the quaternary structure of the H -ATPase is the hexamer and that a relationship seems to exist between ATPase function and the aggregation state of the hexamer. © 2019 by the authors.
  • The plasma membrane H%2b-ATPase was purified from the yeast K. lactis. The oligomeric state of the H%2b-ATPase is not known. Size exclusion chromatography displayed two macromolecular assembly states (MASs) of different sizes for the solubilized enzyme. Blue native electrophoresis (BN-PAGE) showed the H%2b-ATPase hexamer in both MASs as the sole/main oligomeric state—in the aggregated and free state. The hexameric state was confirmed in dodecyl maltoside-treated plasma membranes by Western-Blot. Tetramers, dimers, and monomers were present in negligible amounts, thus depicting the oligomerization pathway with the dimer as the oligomerization unit. H%2b-ATPase kinetics was cooperative (n~1.9), and importantly, in both MASs significant differences were determined in intrinsic fluorescence intensity, nucleotide affinity and Vmax; hence suggesting the large MAS as the activated state of the H%2b-ATPase. It is concluded that the quaternary structure of the H%2b-ATPase is the hexamer and that a relationship seems to exist between ATPase function and the aggregation state of the hexamer. © 2019 by the authors.

publication date

  • 2019-01-01