Evidence for copper homeostasis function of metallothionein (MT3) in the hyperaccumulator Thlaspi caerulescens.
Metallothioneins chelate metals and consequently may be a control point of metal homeostasis. Homologous to type 3 metallothioneins, TcMT3 cDNA was identified in the Cd/Zn hyperaccumulator, Thlaspi caerulescens. TcMT3 amino acid sequence showed modifications in the Cys positions when compared with its Arabidopsis orthologue. A structural model established that the MT3 carboxyterminal domain is similar to the beta domain of animal metallothioneins and predicts a smaller cavity to chelate metals for A. thaliana than for T. caerulescens. Functional testing in yeast and Northern blot analysis added further evidence for adaptative variations of MT3 for the maintenance of Cu homeostasis in a metal hyperaccumulator.
Roosens
Nancy H
NH
Laboratoire de Physiologie et Génétique Moléculaire des Plantes, Université Libre de Bruxelles, Campus Plaine (CP 242) Bld du triomphe, B-1050 Brussels, Belgium. nroosens@ulb.ac.be
Bernard
Catherine
C
Leplae
Raphael
R
Verbruggen
Nathalie
N
D000595:Amino Acid Sequence; D006706:Homeostasis; D000090023:Metallothionein 3; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D031227:Thlaspi / Q000502:physiology*
D000090023:Metallothionein 3; D009419:Nerve Tissue Proteins