title: Peroxisomal targeting signal-1 recognition by the TPR domains of human PEX5.
abstract: Many proteins contain targeting signals within their sequences that specify their delivery to particular organelles. The peroxisomal targeting signal-1 (PTS1) is a C-terminal tripeptide that is sufficient to direct proteins into peroxisomes. The PTS1 sequence closely approximates Ser-Lys-Leu-COO-. PEX5, the receptor for PTS1, interacts with the signal via a series of tetratricopeptide repeats (TPRs) within its C-terminal half. Here we report the crystal structure of a fragment of human PEX5 that includes all seven predicted TPR motifs in complex with a pentapeptide containing a PTS1 sequence. Two clusters of three TPRs almost completely surround the peptide, while a hinge region, previously identified as TPR4, forms a distinct structure that enables the two sets of TPRs to form a single binding site. This structure reveals the molecular basis for PTS1 recognition and demonstrates a novel mode of TPR-peptide interaction.
authors: Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors: G J
authors: GJ
authors: Gatto
authors: B V
authors: BV
authors: Geisbrecht
authors: S J
authors: SJ
authors: Gould
authors: J M
authors: JM
authors: Berg
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002850:Chromatography, Gel; D018360:Crystallography, X-Ray; D005454:Fluorescence Polarization; D006801:Humans; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D021382:Protein Sorting Signals / Q000235:genetics / Q000502:physiology*; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: C000614264:PEX5 protein, human; D010446:Peptide Fragments; D000074435:Peroxisome-Targeting Signal 1 Receptor; D021382:Protein Sorting Signals; D018160:Receptors, Cytoplasmic and Nuclear