title: A native Zn/Cd pumping P(1B) ATPase from natural overexpression in a hyperaccumulator plant.
abstract: We report here the first purification of a P(1B) type ATPase, a group of transporters that occurs in bacteria, plants and animals incl. humans, from a eukaryotic organism in native state. TcHMA4 is a P(1B) type ATPase that is highly expressed in the Cd/Zn hyperaccumulator plant Thlaspi caerulescens and contains a C-terminal 9-histidine repeat. After isolation from roots, we purified TcHMA4 protein via metal affinity chromatography. The purified protein exhibited Cd- and Zn-activated ATPase activity after reconstitution into lipid vesicles, showing that it was in its native state. Gels of crude root extract and of the purified protein revealed TcHMA4-specific bands of about 50 and 60kDa, respectively, while the TcHMA4 mRNA predicts a single protein with a size of 128kDa. This indicates the occurrence of post-translational processing; the properties of the two bands were characterised by their activity and binding properties.
authors.affiliation: Universität Konstanz, Fachbereich Biologie, 78457 Konstanz, Germany.
authors.forename: Aravind
authors.initials: A
authors.lastname: Parameswaran
authors.forename: Barbara
authors.initials: B
authors.lastname: Leitenmaier
authors.forename: Mingjie
authors.initials: M
authors.lastname: Yang
authors.forename: Peter M H
authors.initials: PM
authors.lastname: Kroneck
authors.forename: Wolfram
authors.initials: W
authors.lastname: Welte
authors.forename: Gabriela
authors.initials: G
authors.lastname: Lutz
authors.forename: Ashot
authors.initials: A
authors.lastname: Papoyan
authors.forename: Leon V
authors.initials: LV
authors.lastname: Kochian
authors.forename: Hendrik
authors.initials: H
authors.lastname: Küpper
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry*; D004789:Enzyme Activation; D010936:Plant Extracts / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D017494:Proton Pumps / Q000737:chemistry*; D013379:Substrate Specificity; D031227:Thlaspi / Q000201:enzymology*; D015854:Up-Regulation; D015032:Zinc / Q000737:chemistry*