Search Results - (Author, Cooperation:N. J. Robinson)

2011-07-08

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Adenosine Triphosphatases/genetics/metabolism ; Bacterial Proteins/*chemistry/*metabolism ; Biological Transport ; Cation Transport Proteins/genetics/metabolism ; Copper/*metabolism ; Crystallography, X-Ray ; Hepatolenticular Degeneration/enzymology/genetics/metabolism ; Humans ; Legionella pneumophila/*chemistry ; Menkes Kinky Hair Syndrome/enzymology/genetics ; Protein Structure, Tertiary ; Structure-Activity Relationship

1399-3054

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Evidence for the presence of the metal-binding protein metallothionein, MT, in higher plants is equivocal. Although a number of MT-like metal complexes have been isolated from plants, the chemical structures of most of these compounds have not been fully elucidated. Recently a novel class of plant peptides, poly (γ-glutamylcysteinyl) glycines, (γEC)nG, have been discovered. These peptides bind metal ions, and in the presence of such ions the amount of (γEC), G in plant cells increases. The presence of peptide bonds through the γ-carboxyl group of glutamate, rather than the α-carboxyl group, suggests that these peptides are not encoded by structural genes but are the products of biosynthetic pathways. Cells which are resistant to supra-optimal concentrations of certain metal ions over-produce (γEC)n G. (γEC)n G. may be functional analogues of MT. Whether or not some plants also produce MT is an important question which remains to be answered.

Electronic Resource

1432-2048

Copper tolerance ; Metallothionein ; Mimulus (copper tolerant)

Springer Online Journal Archives 1860-2000

Biology

Abstract A Cu-complex was isolated from the roots of copper-tolerant Mimulus guttatus. The elution volume of the complex determined by gel permeation chromatography was similar to that of rat-liver cadmium thionein. The complex was heat stable, had a relatively high ratio of absorbance at 254 nm: 280 nm and incorporated 35S. The complex, purified using a combination of gel permeation chromatography and anion-exchange chromatography, contained more glutamine/glutamic acid and glycine residues than mammalian metallothioneins. The amount of the complex in roots increased after 5 h growth in a solution containing 16 μM Cu. Induction was preceded by an increase in the concentrations in root tissue of unknown compounds containing sulphur which may serve as precursors. The availability of these compounds appeared to regulate the rate of synthesis of this Cu-complex.

Electronic Resource

1573-5036

aluminium genotype ; root cation-exchange capacity

Springer Online Journal Archives 1860-2000

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Abstract Genotypic differences in aluminium (Al) tolerance hold considerable promise in overcoming an important limitation to plant growth in acid soils. Little is known, however, about the biochemical basis of such differences. Extracellular properties, particularly low root cation-exchange capacity (CEC), have been associated with Al tolerance, since roots of low CEC adsorb less Al than do those of high CEC. A solution culture study was conducted in which 12 plant species (monocots and dicots) were grown in solution culture of low ionic strength (ca 2 mM) for 8 d at four Al concentrations (0, 16, 28 and 55 μM). The species differed significantly in Al tolerance as shown by differences in root length. Root length relative to that of the same species grown in the absence of Al varied from 6 to 117% at 16 μM Al, and from 6 to 75% at 28 μM Al. Species tolerance of Al was not closely associated with differences in root CEC. Although in some species Al sensitivity was associated with high adsorption of Al during a 10- or 40-min exposure to Al (expressed on a fresh mass or root length basis), this was not a good predictor of Al tolerance across all species studied.

Electronic Resource