| Autor: |
Kropat J; Department of Chemistry and Biochemistry, and., Gallaher SD; Department of Chemistry and Biochemistry, and., Urzica EI; Department of Chemistry and Biochemistry, and., Nakamoto SS; Department of Chemistry and Biochemistry, and., Strenkert D; Department of Chemistry and Biochemistry, and., Tottey S; Department of Chemistry and Biochemistry, and., Mason AZ; Institute for Integrated Research in Materials, Environments, and Societies, California State University, Long Beach, CA 90840., Merchant SS; Department of Chemistry and Biochemistry, and Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095; and sabeeha@chem.ucla.edu. |
| Jazyk: |
angličtina |
| Zdroj: |
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2015 Mar 03; Vol. 112 (9), pp. 2644-51. Date of Electronic Publication: 2015 Feb 02. |
| DOI: |
10.1073/pnas.1422492112 |
| Abstrakt: |
Inorganic elements, although required only in trace amounts, permit life and primary productivity because of their functions in catalysis. Every organism has a minimal requirement of each metal based on the intracellular abundance of proteins that use inorganic cofactors, but elemental sparing mechanisms can reduce this quota. A well-studied copper-sparing mechanism that operates in microalgae faced with copper deficiency is the replacement of the abundant copper protein plastocyanin with a heme-containing substitute, cytochrome (Cyt) c6. This switch, which is dependent on a copper-sensing transcription factor, copper response regulator 1 (CRR1), dramatically reduces the copper quota. We show here that in a situation of marginal copper availability, copper is preferentially allocated from plastocyanin, whose function is dispensable, to other more critical copper-dependent enzymes like Cyt oxidase and a ferroxidase. In the absence of an extracellular source, copper allocation to Cyt oxidase includes CRR1-dependent proteolysis of plastocyanin and quantitative recycling of the copper cofactor from plastocyanin to Cyt oxidase. Transcriptome profiling identifies a gene encoding a Zn-metalloprotease, as a candidate effecting copper recycling. One reason for the retention of genes encoding both plastocyanin and Cyt c6 in algal and cyanobacterial genomes might be because plastocyanin provides a competitive advantage in copper-depleted environments as a ready source of copper. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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