The 32 kDa tonoplast polypeptide Di associated with the V-type H+-ATPase of Mesembryanthemum crystallinum L. in the CAM state: A proteolytically processed subunit B?

FEBS Lett. 1996 Jul 8;389(3):314-8. doi: 10.1016/0014-5793(96)00556-x.

Abstract

In the facultative halophyte Mesembryanthemum crystallinum, the salt- or age-induced transition to crassulacean acid metabolism (CAM) leads to the occurrence of a tonoplast-bound 32 kDa polypeptide (Di). The alignment of its N-terminal protein sequence with protein sequences of recently cloned higher plant V-ATPase B-subunits indicates that Di may be derived from subunit B by proteolytic removal of a protein fragment of about 20 kDa from its N-terminus. Furthermore, an antiserum directed against Di cross-reacts with subunit B from Nicotiana tabacum. It inhibits both proton pumping and ATP hydrolysis of the holoenzyme in M. crystallinum. As Di remains firmly attached to the holoenzyme the proteolytic processing may have functional implications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Amino Acid Sequence
  • Antibodies / immunology
  • Blotting, Western
  • Molecular Sequence Data
  • Peptides / chemistry
  • Peptides / metabolism
  • Plants / enzymology*
  • Plants / metabolism
  • Protein Binding
  • Protein Conformation
  • Protein Processing, Post-Translational*
  • Proton Pumps / metabolism
  • Proton-Translocating ATPases / chemistry*
  • Proton-Translocating ATPases / immunology
  • Proton-Translocating ATPases / metabolism
  • Sequence Alignment
  • Vacuolar Proton-Translocating ATPases*

Substances

  • Antibodies
  • Peptides
  • Proton Pumps
  • Adenosine Triphosphate
  • Vacuolar Proton-Translocating ATPases
  • Proton-Translocating ATPases