title: Evidence for five divergent thioredoxin h sequences in Arabidopsis thaliana.
abstract: Five different clones encoding thioredoxin homologues were isolated from Arabidopsis thaliana cDNA libraries. On the basis of the sequences they encode divergent proteins, but all belong to the cytoplasmic thioredoxins h previously described in higher plants. The five proteins obtained by overexpressing the coding sequences in Escherichia coli present typical thioredoxin activities (NADP(+)-malate dehydrogenase activation and reduction by Arabidopsis thioredoxin reductase) despite the presence of a variant active site, Trp-Cys-Pro-Pro-Cys, in three proteins in place of the canonical Trp-Cys-Gly-Pro-Cys sequence described for thioredoxins in prokaryotes and eukaryotes. Southern blots show that each cDNA is encoded by a single gene but suggest the presence of additional related sequences in the Arabidopsis genome. This very complex diversity of thioredoxins h is probably common to all higher plants, since the Arabidopsis sequences appear to have diverged very early, at the beginning of plant speciation. This diversity allows the transduction of a redox signal into multiple pathways.
authors.affiliation: Laboratoire de Physiologie et Biologie Moléculaire des Plantes, Université, Perpignan, France.
authors.forename: R
authors.initials: R
authors.lastname: Rivera-Madrid
authors.forename: D
authors.initials: D
authors.lastname: Mestres
authors.forename: P
authors.initials: P
authors.lastname: Marinho
authors.forename: J P
authors.initials: JP
authors.lastname: Jacquot
authors.forename: P
authors.initials: P
authors.lastname: Decottignies
authors.forename: M
authors.initials: M
authors.lastname: Miginiac-Maslow
authors.forename: Y
authors.initials: Y
authors.lastname: Meyer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics*; D018076:DNA, Complementary; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D013879:Thioredoxins