Substrate binding changes conformation of the α-, but not the β-subunit of mitochondrial processing peptidase

Oleksandr Gakh, Tomas Obsil, Jiri Adamec, Jaroslav Spizek, Evzen Amler, Jiri Janata, Frantisek Kalousek

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Lifetime analysis of tryptophan fluorescence of the mitochondrial processing peptidase (MPP) from Saccharomyces cerevisiae clearly proved that substrate binding evoked a conformational change of the α-subunit while presence of substrate influenced neither the lifetime components nor the average lifetime of the tryptophan excited state of the β-MPP subunit. Interestingly, lifetime analysis of tryptophan fluorescence decay of the α-MPP subunit revealed about 11% of steady-state fractional intensity due to the long-lived lifetime component, indicating that at least one tryptophan residue is partly buried at the hydrophobic microenvironment. Computer modeling, however, predicted none of three tryptophans, which the α-sub-unit contains, as deeply buried in the protein matrix. We conclude this as a consequence of a possible dimeric (oligomeric) structure.

Original languageEnglish (US)
Pages (from-to)392-396
Number of pages5
JournalArchives of Biochemistry and Biophysics
Issue number2
StatePublished - Jan 15 2001



  • Mitochondrial processing peptidase (MPP)
  • Structure
  • Tryptophan fluorescence
  • Yeast

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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