title: Three thioredoxin targets in the inner envelope membrane of chloroplasts function in protein import and chlorophyll metabolism.
abstract: Thioredoxins (Trxs) are ubiquitous small proteins with a redox-active disulfide bridge. In their reduced form, they constitute very efficient protein disulfide oxidoreductases. In chloroplasts, two types of Trxs (f and m) coexist and play central roles in the regulation of the Calvin cycle and other processes. Here, we identified a class of Trx targets in the inner plastid envelope membrane of chloroplasts that share a CxxC motif approximately 73 aa from their carboxyl-terminal end. Members of this group belong to a superfamily of Rieske iron-sulfur proteins involved in protein translocation and chlorophyll metabolism. These proteins include the protein translocon protein TIC55, the precursor NADPH:protochlorophyllide oxidoreductase translocon protein PTC52, which operates as protochlorophyllide a-oxygenase, and the lethal leaf spot protein LLS1, which is identical with pheophorbide a oxygenase. The role of these proteins in dark/light regulation and oxidative control by the Trx system is discussed.
authors: Lehrstuhl für Pflanzenphysiologie, Universität Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany.
authors: Sandra
authors: S
authors: Bartsch
authors: Julie
authors: J
authors: Monnet
authors: Kristina
authors: K
authors: Selbach
authors: Françoise
authors: F
authors: Quigley
authors: John
authors: J
authors: Gray
authors: Diter
authors: D
authors: von Wettstein
authors: Steffen
authors: S
authors: Reinbothe
authors: Christiane
authors: C
authors: Reinbothe
mesh_terms: D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D002846:Chromatography, Affinity; D003624:Darkness; D001467:Hordeum / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D002734:Chlorophyll; D013879:Thioredoxins