| Abstract Detail
Organelle Biology Reumann, Sigrun [1], Antonicelli, Esteban [2], Siemsen, Tanja [3], Lingner, Thomas [4], Morgenstern, Burkhard [4], Meinicke, Peter [4]. Predicting PTS1/2-Targeted Matrix Proteins of Plant Peroxisomes from Genome Sequences. Even though significant progress has been made in identifying plant peroxisomal proteins by large-scale proteomics approaches, peroxisome variants of minor plant tissue will not be accessible to experimental approaches in the near future, reiterating the need to predict unknown peroxisomal matrix proteins from genome sequences. Most matrix proteins are targeted to plant peroxisomes by the peroxisome targeting signal type 1 (PTS1) or type 2 (PTS2). The two basic questions regarding the prediction of PTS1/2 proteins are the following: (i) Which PTS1 tripeptides and PTS2 nonapeptides are functional peroxisome targeting signals for plant peroxisomes, and (ii) which amino acid residues in close proximity to the PTS1/2 peptides essentially determine the targeting function of the PTS1/2 peptides. We build predictive models by bioinformatics analyses and validate their accuracy by experimental approaches. By taking advantage of plant EST databases we generated a set of more than 1000 plant PTS1 proteins that allowed the recognition of about ten previously unrecognized minor PTS1 peptides. When PTS1 domains of representative ESTs with predicted novel PTS1 tripeptides were fused at their N-terminus to enhanced yellow fluorescent protein (EYFP) and expressed transiently in onion epidermal cells, all predicted novel PTS1s targeted EYFP to peroxisomes. The recognition of the novel PTS1 peptides allows a significant extension of the plant peroxisomal protein database AraPerox (www.araperox.uni-goettingen.de). Based on (i) a comparative analysis of the amino acid residue distribution in PTS1 domains taking into consideration more than 100 physico-biochemical properties and (ii) an identification of discriminative features in terms of position-specific amino acid weights, the peroxisome targeting probability of unknown proteins now can directly be predicted from its primary structure. Site-directed mutagenesis of representative PTS1 domains provides experimental support for the predicted function of specific residues in protein targeting to plant peroxisomes.
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1 - Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Biochemistry, Justus-von-Liebig-Weg 11, Goettingen, D-37077, Germany
2 - Clemens Schöpf Institute, Biochemistry Department
3 - Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Biochemistry
4 - Institute for Microbiology, Dept. Bioinformatics
Keywords:
bioinformatics
protein targeting
peroxisomes
pattern definition.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P18009
Abstract ID:289 |
