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The Hansenula polymorpha peroxisomal targeting signal 1 receptor, Pex5p, functions as a tetramer
Author(s) -
Moscicka Katarzyna B.,
Klompmaker Sandra H.,
Wang Dongyuan,
van der Klei Ida J.,
Boekema Egbert J.
Publication year - 2007
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.03.061
Subject(s) - peroxisomal targeting signal , peroxisome , tetramer , receptor , biology , biochemistry , chemistry , biophysics , enzyme
We have studied Hansenula polymorpha Pex5p and Pex20p, peroxins involved in peroxisomal matrix protein import. In vitro binding experiments suggested that H. polymorpha Pex5p and Pex20p physically interact. We used single particle electron microscopy (EM) to analyze the structure of purified Pex5p and its possible association with Pex20p. Upon addition of Pex20p, a multimeric Pex20p complex was observed to be associated to the periphery of the Pex5p tetramer. In this Pex5p–Pex20p complex, the conformation of tetrameric Pex5p had changed from a closed conformation with a diameter of 115 Å into an open conformation of 134 Å. EM also indicated that the Pex5p–Pex20p complex was capable to bind native, folded catalase, a peroxisomal PTS1 protein. This suggests that the Pex5p–Pex20p complex may be functional as receptor complex.