Abstract:
The basic amino acid histidine inhibited yeast cell growth more severely than
lysine and arginine. Overexpression of CTR1, which encodes a
high-affinity copper transporter on the plasma membrane, or addition of copper
to the medium alleviated this cytotoxicity. However, the intracellular level of
copper ions was not decreased in the presence of excess histidine. These results
indicate that histidine cytotoxicity is associated with low copper availability
inside cells, not with impaired copper uptake. Furthermore, histidine did not
affect cell growth under limited respiration conditions, suggesting that
histidine cytotoxicity is involved in deficiency of mitochondrial copper.
