The Arabidopsis thaliana CUTA gene encodes an evolutionarily conserved copper binding chloroplast protein
Article first published online: 10 JUN 2003
The Plant Journal
Volume 34, Issue 6, pages 856–867, June 2003
How to Cite
Burkhead, J. L., Abdel-Ghany, S. E., Morrill, J. M., Pilon-Smits, E. A. H. and Pilon, M. (2003), The Arabidopsis thaliana CUTA gene encodes an evolutionarily conserved copper binding chloroplast protein. The Plant Journal, 34: 856–867. doi: 10.1046/j.1365-313X.2003.01769.x
- Issue published online: 10 JUN 2003
- Article first published online: 10 JUN 2003
- Received 7 January 2003; revised 11 March 2003; accepted 14 March 2003.
- targeting sequence
The Arabidopsis thaliana CUTA gene encodes a 182-amino-acid-long putative precursor of a chloroplast protein with high sequence similarity to evolutionarily conserved prokaryotic proteins implicated in copper tolerance. Northern analysis indicates that AtCUTA mRNA is expressed in all major tissue types. Analysis of cDNA clones and RT-PCR with total mRNA revealed alternative splicing of AtCUTA by retention of an intron. The intron-containing mRNA encodes a truncated 156-amino-acid protein as a result of stop codons in the included intron. The sequence of AtCutAp encoded by the fully spliced transcript suggests that the precursor consists of three domains: an N-terminal chloroplast transit sequence of 70 residues, followed by a domain with prokaryotic signal-sequence-like characteristics and finally the most conserved C-terminal domain. The N-terminal chloroplast transit sequence was functional to route a passenger protein into isolated pea chloroplasts with possible sorting to the envelope. Chloroplast localization was confirmed by Western blot analysis of isolated and fractionated chloroplasts. Recombinant AtCutA protein was expressed in Escherichia coli without the N-terminal 70-amino-acid chloroplast transit sequence. This recombinant AtCutAp was routed to the bacterial periplasm of E. coli. Purified recombinant AtCutAp is tetrameric and selectively binds Cu(II) ions with an affinity comparable to that reported for mammalian prion proteins.