new class of proteins capable of binding transition metals

• Published in: Plant molecular biology Vol. 41; no. 1; pp. 139 - 150
• Main Authors: Dykema, P.E, Sipes, P.R, Marie, A, Biermann, B.J, Crowell, D.N, Randall, S.K
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.09.1999
• Subjects: Amino Acid Sequence; amino acid sequences; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; binding; binding proteins; Binding Sites; chemical reactions; Chromatography, Affinity; complementary DNA; copper; DNA, Complementary - chemistry; DNA, Complementary - genetics; E coli; Exons; farnesylation; genes; Genes, Plant - genetics; Glycine max; Introns; isoprenoids; isoprenylation; lipoproteins; metal ions; Metals; Metals - metabolism; mevalonic acid; Molecular Sequence Data; nickel; Nicotiana; Nicotiana - cytology; Nicotiana - genetics; Nicotiana - metabolism; Nicotiana tabacum; nucleotide sequences; Nutritional requirements; Plant growth; plant proteins; Plant Proteins - genetics; Plant Proteins - metabolism; Plant species; Plants, Toxic; Protein Binding; Protein Prenylation; Proteins; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Soybeans; zinc
• DOI: 10.1023/A:1006367609556
• ISSN: 0167-4412

Ion uptake, transport, and sequestration are essential to meet the nutritional requirements for plant growth and development. Furthermore, regulation of these processes is critical for plants to tolerate toxic levels of ions. The examination of isoprenylated proteins encoded by Arabidopsis thaliana and Glycine max cDNAs revealed a unique family of proteins containing putative metal-binding motifs (the core sequence is M/LXCXXC). Here, we describe this new class of proteins, which are capable of being isoprenylated and binding transition metal ions. Members of this family contain consensus isoprenylation (CaaX) sites, which we demonstrate are efficiently isoprenylated in vitro. ATFP3, a representative of the Arabidopsis family, was expressed in Escherichia coli and examined for metal-binding activity in vitro. Analysis of the interaction of ATFP3 with metal-chelating columns (IMAC) suggested that it binds to Cu(2+), Ni(2+), or Zn(2+). To test whether proteins with these characteristics are present in other plant species, tobacco BY2 cells were labeled in vivo with [(14)C]mevalonate and the resulting mevalonate-labeled proteins were tested for metal-binding activity. Several soluble, isoprenylated proteins which bound copper-IMAC columns were revealed. Consistent with a wide-spread distribution of these proteins in plants, their presence was observed in Arabidopsis, soybean, and tobacco.