title: Substrate binding changes conformation of the alpha-, but not the beta-subunit of mitochondrial processing peptidase.
abstract: 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 alpha-subunit while presence of substrate influenced neither the lifetime components nor the average lifetime of the tryptophan excited state of the beta-MPP subunit. Interestingly, lifetime analysis of tryptophan fluorescence decay of the alpha-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 alpha-subunit contains, as deeply buried in the protein matrix. We conclude this as a consequence of a possible dimeric (oligomeric) structure.
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague.
authors.forename: O
authors.initials: O
authors.lastname: Gakh
authors.forename: T
authors.initials: T
authors.lastname: Obsil
authors.forename: J
authors.initials: J
authors.lastname: Adamec
authors.forename: J
authors.initials: J
authors.lastname: Spizek
authors.forename: E
authors.initials: E
authors.lastname: Amler
authors.forename: J
authors.initials: J
authors.lastname: Janata
authors.forename: F
authors.initials: F
authors.lastname: Kalousek
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003198:Computer Simulation; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D005453:Fluorescence; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D011498:Protein Precursors / Q000378:metabolism*; D020673:Protein Renaturation; D021122:Protein Subunits; D011522:Protons; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D017356:Synchrotrons; D014364:Tryptophan / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D000096122:Mitochondrial Processing Peptidase
chemical_list: D008666:Metalloendopeptidases; D011498:Protein Precursors; D021122:Protein Subunits; D011522:Protons; D011994:Recombinant Proteins; D014364:Tryptophan; D000096122:Mitochondrial Processing Peptidase