Ca2+-ATPase membrane crystals in sarcoplasmic reticulum. The effect of trypsin digestion.

L. Dux, A. Martonosi

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

Vanadate induces the formation of two-dimensional crystalline arrays of Ca2+-ATPase molecules in sarcoplasmic reticulum. The Ca2+-ATPase membrane crystals are evenly distributed among the terminal cisternae and longitudinal tubules of sarcoplasmic reticulum, but very few crystals were observed in the T tubules. Tryptic cleavage of the Ca2+ transport ATPase into two major fragments (A and B) did not interfere with the vanadate-induced formation of membrane crystals. The ability of Ca2+-ATPase to crystallize was lost after further cleavage of the A fragment into the A1 and A2 subfragments that is known to be accompanied by loss of Ca2+ uptake. Vanadate (0.1-5 mM) inhibited the secondary cleavage of Ca2+-ATPase by trypsin suggesting that the susceptibility of the tryptic cleavage sites is influenced either by the conformation of the enzyme or by the formation of ATPase crystals.

Original languageEnglish
Pages (from-to)10111-10115
Number of pages5
JournalJournal of Biological Chemistry
Volume258
Issue number16
Publication statusPublished - Aug 25 1983

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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