A novel subunit of vacuolar H+-ATPase related to the b subunit of F-ATpases

Lubica Supekova*, Mohammed Sbia, Frantisek Supek, Yuemei Ma, Nathan Nelson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The subunit structure of the vacuolar H+-ATPase (V-ATPase) membrane sector is not entirely known. The proteolipid is the only subunit that has been implicated in the mechanism of energy transfer in the enzyme. We have identified a protein (M16) that co-purifies with the V-ATPase complex from bovine chromaffin granules. Information obtained from the amino acid sequence of a proteolytic fragment of M16 was used to clone a bovine adrenal cDNA encoding this protein. The cDNA encodes a hydrophilic protein of 118 amino acid residues with a calculated molecular mass of 13682Da. Amino acid sequence analysis revealed that M16 exhibits a significant homology to subunit b of F-ATPases. M16 is smaller than subunit b and contains no apparent transmembrane segment in its N terminus. The remainder of subunit b is related to M16 not only by its amino acid sequence but also in its predicted structure of helix-turn-helix. The structural and evolutionary implications of these findings are discussed.

Original languageEnglish
Pages (from-to)1147-1156
Number of pages10
JournalJournal of Experimental Biology
Issue number5
StatePublished - May 1996


  • Membrane
  • Proton pumps
  • Subunit structure
  • V-ATPase
  • Vacuolar system


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