title: Chloroplast proteomics and the compartmentation of plastidial isoprenoid biosynthetic pathways.
abstract: Recent advances in the proteomic field have allowed high-throughput experiments to be conducted on chloroplast samples. Many proteomic investigations have focused on either whole chloroplast or sub-plastidial fractions. To date, the Plant Protein Database (PPDB, Sun et al., 2009) presents the most exhaustive chloroplast proteome available online. However, the accurate localization of many proteins that were identified in different sub-plastidial compartments remains hypothetical. Ferro et al. (2009) went a step further into the knowledge of Arabidopsis thaliana chloroplast proteins with regards to their accurate localization within the chloroplast by using a semi-quantitative proteomic approach known as spectral counting. Their proteomic strategy was based on the accurate mass and time tags (AMT) database approach and they built up AT_CHLORO, a comprehensive chloroplast proteome database with sub-plastidial localization and curated information on envelope proteins. Comparing these two extensive databases, we focus here on about 100 enzymes involved in the synthesis of chloroplast-specific isoprenoids. Well known pathways (i.e. compartmentation of the methyl erythritol phosphate biosynthetic pathway, of tetrapyrroles and chlorophyll biosynthesis and breakdown within chloroplasts) validate the spectral counting-based strategy. The same strategy was then used to identify the precise localization of the biosynthesis of carotenoids and prenylquinones within chloroplasts (i.e. in envelope membranes, stroma, and/or thylakoids) that remains unclear until now.
authors.affiliation: Laboratoire de Physiologie Cellulaire Végétale, UMR 5168, CEA, CNRS, INRA, Université Joseph Fourier, iRTSV, CEA-Grenoble, 38054 Grenoble-cedex 9, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Joyard
authors.forename: Myriam
authors.initials: M
authors.lastname: Ferro
authors.forename: Christophe
authors.initials: C
authors.lastname: Masselon
authors.forename: Daphné
authors.initials: D
authors.lastname: Seigneurin-Berny
authors.forename: Daniel
authors.initials: D
authors.lastname: Salvi
authors.forename: Jérôme
authors.initials: J
authors.lastname: Garin
authors.forename: Norbert
authors.initials: N
authors.lastname: Rolland
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D002734:Chlorophyll / Q000096:biosynthesis / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D030562:Databases, Protein; D010940:Plant Proteins / Q000235:genetics*; D018087:Plastids / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D017386:Sequence Homology, Amino Acid
chemical_list: D010940:Plant Proteins; D002734:Chlorophyll