Open AccessFluorescence analysis of the Hansenula polymorpha peroxisomal targeting signal‐1 receptor, Pex5p
Author(s) -
Boteva Raina,
Koek Anne,
Visser Nina V.,
Visser Antonie J.W.G.,
Krieger Elmar,
Zlateva Theodora,
Veenhuis Marten,
van der Klei Ida
Publication year - 2003
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2003.03827.x
Subject(s) - fluorescence , chemistry , peroxisome , quenching (fluorescence) , peroxisomal targeting signal , monomer , fluorescence spectroscopy , tripeptide , biophysics , biochemistry , receptor , biology , peptide , organic chemistry , polymer , physics , quantum mechanics
Correct sorting of newly synthesized peroxisomal matrix proteins is dependent on a peroxisomal targeting signal (PTS). So far two PTSs are known. PTS1 consists of a tripeptide that is located at the extreme C terminus of matrix proteins and is specifically recognized by the PTS1‐receptor Pex5p. We studied Hansenula polymorpha Pex5p (HpPex5p) using fluorescence spectroscopy. The intensity of Trp fluorescence of purified HpPex5p increased by 25% upon shifting the pH from pH 6.0 to pH 7.2. Together with the results of fluorescence quenching by acrylamide, these data suggest that the conformation of HpPex5p differs at these two pH values. Fluorescence anisotropy decay measurements revealed that the pH affected the oligomeric state of HpPex5p, possibly from monomers/dimers at pH 6.0 to larger oligomeric forms at pH 7.2. Addition of dansylated peptides containing a PTS1, caused some shortening of the average fluorescence lifetime of the Trp residues, which was most pronounced at pH 7.2. Our data are discussed in relation to a molecular model of HpPex5p based on the three‐dimensional structure of human Pex5p.