title: A novel plastid-targeted J-domain protein in Arabidopsis thaliana.
abstract: Arabidopsis cDNAs encoding ATJ11, the smallest known J-domain protein, have been isolated and characterized. The precursor protein of 161 amino acid residues was synthesized in vitro and imported by isolated pea chloroplasts where it was localized to the stroma and cleaved to a mature protein of 125 amino acid residues. The mature protein consists of an 80 amino acid J-domain, and N- and C-terminal extensions of 24 and 21 amino acid residues, respectively, which show no similarity to regions in other DnaJ-related proteins. ATJ11 produced in Escherichia coli stimulated the weak ATPase activity of E. coli DnaK, but was unable to stimulate refolding of firefly luciferase by DnaK, and inhibited refolding by DnaK, DnaJ and GrpE. ATJ11 is encoded by a single-copy gene on chromosome 4, and is expressed in all plant organs examined. A paralogue of ATJ11, showing 72% identity, is encoded in a 4.5 Mb duplication of chromosome 4 on chromosome 2. These proteins represent a novel class of J-domain proteins.
authors.affiliation: Department of Plant Sciences and Cambridge Centre for Molecular Recognition, University of Cambridge, UK.
authors.forename: W
authors.initials: W
authors.lastname: Orme
authors.forename: A R
authors.initials: AR
authors.lastname: Walker
authors.forename: R
authors.initials: R
authors.lastname: Gupta
authors.forename: J C
authors.initials: JC
authors.lastname: Gray
mesh_terms: D000251:Adenosine Triphosphatases / Q000187:drug effects / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins; D001665:Binding Sites; D001692:Biological Transport; D015152:Blotting, Northern; D015139:Blotting, Southern; D002736:Chloroplasts / Q000378:metabolism; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D018744:DNA, Plant / Q000235:genetics; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism; D008156:Luciferases / Q000737:chemistry / Q000187:drug effects; D008666:Metalloendopeptidases / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D018087:Plastids / Q000378:metabolism*; D011489:Protein Denaturation; D017510:Protein Folding; D011498:Protein Precursors / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014018:Tissue Distribution
chemical_list: C434494:ATJ11 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D018744:DNA, Plant; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D010940:Plant Proteins; D011498:Protein Precursors; D018749:RNA, Plant; D008156:Luciferases; D008666:Metalloendopeptidases; C489517:chloroplast processing enzyme protein, Arabidopsis; C071986:stromal processing peptidase; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli