title: Proteomic characterization of the Chlamydomonas reinhardtii chloroplast ribosome. Identification of proteins unique to th e70 S ribosome.
abstract: We have conducted a proteomic analysis of the 70 S ribosome from the Chlamydomonas reinhardtii chloroplast. Twenty-seven orthologs of Escherichia coli large subunit proteins were identified in the 50 S subunit, as well as an ortholog of the spinach plastid-specific ribosomal protein-6. Several of the large subunit proteins of C. reinhardtii have short extension or insertion sequences, but overall the large subunit proteins are very similar to those of spinach chloroplast and E. coli. Two proteins of 38 and 41 kDa, designated RAP38 and RAP41, were identified from the 70 S ribosome that were not found in either of the ribosomal subunits. Phylogenetic analysis identified RAP38 and RAP41 as paralogs of spinach CSP41, a chloroplast RNA-binding protein with endoribonuclease activity. Overall, the chloroplast ribosome of C. reinhardtii is similar to those of spinach chloroplast and E. coli, but the C. reinhardtii ribosome has proteins associated with the 70 S complex that are related to non-ribosomal proteins in other species. In addition, the 30 S subunit contains unusually large orthologs of E. coli S2, S3, and S5 and a novel S1-type protein (Yamaguchi, K. et al., (2002) Plant Cell 14, 2957-2974). These additional proteins and domains likely confer functions used to regulate chloroplast translation in C. reinhardtii.
authors.affiliation: Department of Cell Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: María Verónica
authors.initials: MV
authors.lastname: Beligni
authors.forename: Susana
authors.initials: S
authors.lastname: Prieto
authors.forename: Paul A
authors.initials: PA
authors.lastname: Haynes
authors.forename: W Hayes
authors.initials: WH
authors.lastname: McDonald
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Mayfield
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D017353:Gene Deletion; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020543:Proteome / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D018724:Spinacia oleracea / Q000378:metabolism; D013997:Time Factors
chemical_list: D020543:Proteome