A protein from a parasitic microorganism, Rickettsia prowazekii, can cleave the signal sequences of proteins targeting mitochondria

Sakae Kitada, Tsuneo Uchiyama, Tomoyuki Funatsu, Yumiko Kitada, Tadashi Ogishima, Akio Ito

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

The obligate intracellular parasitic bacteria rickettsiae are more closely related to mitochondria than any other microbes investigated to date. A rickettsial putative peptidase (RPP) was found to resemble the α and β subunits of mitochondrial processing peptidase (MPP), which cleaves the transport signal sequences of mitochondrial preproteins. RPP showed completely conserved zinc-binding and catalytic residues compared with β-MPP but barely contained any of the glycine-rich loop region characteristic of α-MPP. When the biochemical activity of RPP purified from a recombinant source was analyzed, RPP specifically hydrolyzed basic peptides and presequence peptides with frequent cleavage at their MPP-processing sites. Moreover, RPP appeared to activate yeast β-MPP so that it processed preproteins with shorter presequences. Thus, RPP behaves as a bifunctional protein that could act as a basic peptide peptidase and a somewhat regulatory protein for other protein activities in rickettsiae. These are the first biological and enzymological studies to report that a protein from a parasitic microorganism can cleave the signal sequences of proteins targeted to mitochondria.

Original languageEnglish
Pages (from-to)844-850
Number of pages7
JournalJournal of bacteriology
Volume189
Issue number3
DOIs
Publication statusPublished - Feb 2007

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology

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