The Difference in Recognition of Terminal Tripeptides as Peroxisomal Targeting Signal 1 between Yeast and Human Is Due to Different Affinities of Their Receptor Pex5p to the Cognate Signal and to Residues Adjacent to It*
- Guenther Lametschwandtner‡,
- Cécile Brocard‡,
- Marc Fransen§¶,
- Paul Van Veldhoven§,
- Johannes Berger‖ and
- Andreas Hartig‡**
- From the ‡Institut fuer Biochemie und Molekulare Zellbiologie der Universitaet Wien and Ludwig Boltzmann-Forschungsstelle fuer Biochemie, Vienna Biocenter, Dr. Bohrgasse 9, A-1030 Wien, Austria, §Katholieke Universiteit Leuven, Faculteit Geneeskunde, Campus Gasthuisberg, Departement Moleculaire Celbiologie, Afdeling Farmakologie, Herestraat 49, B-3000 Leuven, Belgium, and ‖Klinisches Institut für Neurologie der Universitaet Wien, Schwarzspanierstrasse 17, A-1090 Wien, Austria
Abstract
Pex5p is the receptor for the peroxisomal targeting signal 1 (PTS1) that consists of a C-terminal tripeptide (consensus (S/A/C)(K/R/H)(L/M)). Hexadecapeptides recognized by Pex5p from Homo sapiens and Saccharomyces cerevisiaewere identified by screening a two-hybrid peptide library, and the targeting ability of the peptides was demonstrated using the green fluorescent protein as reporter. The PTS1 receptors recognized in a species-specific manner a broad range of C-terminal tripeptides, and these are reported herein. In addition, residues upstream of the tripeptide influenced the strength of the interaction in the two-hybrid system as well as in an in vitro competition assay. In peptides interacting with the human protein, hydrophobic residues were found with high frequency especially at positions −2 and −5, whereas peptides interacting with S. cerevisiae Pex5p were more hydrophilic and frequently contained arginine at position −2. In instances where the terminal tripeptide deviated from the consensus, upstream residues exerted a greater influence on the ability of the hexadecapeptides to bind Pex5p.
Footnotes
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↵* This work was supported by the Fonds zur Foerderung der wissenschaftlichen Forschung, Austria, Grants P-10725-MOB, P-12118-MOB (to A. H.), and P-12073-MED (to J. B.) and by a grant from the Geconcerteerde Onderzoeksactie van de Vlaamse Gemeenschap, Belgium (to P. V. V.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵¶ Recipient of a postdoctoral fellowship from the Fonds voor Wetenschappelijk Onderzoek, Belgium.
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↵** To whom correspondence should be addressed. Tel.: 43-1-4277-52817; Fax: 43-1-4277-9528; E-mail: AH{at}abc.UniVie.AC.AT.
- Abbreviations:
- PTS1 and -2
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peroxisomal targeting signal 1 and 2, respectively
- GFP
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green fluorescent protein of A. victorea
- EGFP
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enhanced GFP
- HSA
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human serum albumin
- PCR
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polymerase chain reaction
- SC
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synthetic complete medium
- TPR tetratricopeptide repeat
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TRITC, tetramethylrhodamine isothiocyanate
- bp
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base pair(s).
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- Received April 30, 1998.
- Revision received August 4, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
