Response mechanism of mine-isolated fungus Aspergillus niger IOC 4687 to copper stress determined by proteomics.

Proteomic analysis of the fungus Aspergillus niger showed that its capacity to absorb metals was boosted by physiological modification under metal stress conditions. To investigate the proteome elicited by copper stress, the mine-isolated strain A. niger IOC 4687 was cultured in the absence (control) or presence of copper ions (50 mg L-1) for 72 h. Protein extract from each treatment was analyzed by nano-liquid chromatography-mass spectrometry and proteins were identified using PEAKS Studio 8.5 software. Grouping proteins by functional category showed that antioxidant enzymes, such as catalase, superoxide dismutase, and cytochrome c peroxidase, were present in both treatments. However, heat shock proteins (Hsp60 and Hsp70) and some metalloproteins (LMBR1 domain protein and A. niger contig An09c0040) were only observed after copper treatment. These proteins were the cellular response to the stress conditions. In conclusion, significant changes in the proteome of A. niger were observed due to the presence of copper.