Mobilization of selenium by a selenium-dependent bacterium

Copper organo-chelators in Aspergillus fumigatus and Penicillium chrysogenum

The presence of copper in the growth medium induces the biosynthesis of several low-mol-wt copper ogano-chelators in Aspergillus fumigatus and Penicillium chrysogenum. By use of P. chrysogenum, we were able to prepare several low-mol-wt metallothionein chelators, as well as several short-chain copper chelatins. The amino acid composition of a chelatin of mol wt approx 799 Da revealed the presence of cysteine, glutamic acid, glycine, and leucine. Use of A. fumigatus led to fewer copper chelators and one very short-chain peptide: a chelatin of mol wt approx 624 Da. composed of four amino acids, asparagine, glutamic acid, cysteine, and glycine. These results may confirm our assumption that fungi detoxify the deleterious action of toxic elements by producing high levels of heavy metal chelators/chelatins.