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Manganese specificity determinants in the Arabidopsis metal/H+ antiporter CAX2.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2003 Feb 21; Vol. 278 (8), pp. 6610-7. Date of Electronic Publication: 2002 Dec 22. - Publication Year :
- 2003
-
Abstract
- In plants and fungi, vacuolar transporters help remove potentially toxic cations from the cytosol. Metal/H(+) antiporters are involved in metal sequestration into the vacuole. However, the specific transport properties and the ability to manipulate these transporters to alter substrate specificity are poorly understood. The Arabidopsis thaliana cation exchangers, CAX1 and CAX2, can both transport Ca(2+) into the vacuole. There are 11 CAX-like transporters in Arabidopsis; however, CAX2 was the only characterized CAX transporter capable of vacuolar Mn(2+) transport when expressed in yeast. To determine the domains within CAX2 that mediate Mn(2+) specificity, six CAX2 mutants were constructed that contained different regions of the CAX1 transporter. One class displayed no alterations in Mn(2+) or Ca(2+) transport, the second class showed a reduction in Ca(2+) transport and no measurable Mn(2+) transport, and the third mutant, which contained a 10-amino acid domain from CAX1 (CAX2-C), showed no reduction in Ca(2+) transport and a complete loss of Mn(2+) transport. The subdomain analysis of CAX2-C identified a 3-amino acid region that is responsible for Mn(2+) specificity of CAX2. This study provides evidence for the feasibility of altering substrate specificity in a metal/H(+) antiporter, an important family of transporters found in a variety of organisms.
- Subjects :
- Amino Acid Sequence
Antiporters chemistry
Antiporters genetics
Arabidopsis genetics
Arabidopsis Proteins chemistry
Arabidopsis Proteins genetics
Base Sequence
Calcium metabolism
Calcium-Binding Proteins chemistry
Calcium-Binding Proteins genetics
Molecular Sequence Data
Mutagenesis, Site-Directed
Polymerase Chain Reaction
Recombinant Fusion Proteins chemistry
Recombinant Fusion Proteins metabolism
Recombinant Proteins chemistry
Recombinant Proteins metabolism
Sequence Alignment
Sequence Homology, Amino Acid
Substrate Specificity
Antiporters metabolism
Arabidopsis metabolism
Arabidopsis Proteins metabolism
Calcium-Binding Proteins metabolism
Cation Transport Proteins
Hydrogen-Ion Concentration
Manganese metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 278
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 12496310
- Full Text :
- https://doi.org/10.1074/jbc.M209952200