Functional sulfurtransferase is associated with mitochondrial complex I from Yarrowia lipolytica, but is not required for assembly of its iron-sulfur clusters.

Here, we report that in the obligate aerobic yeast Yarrowia lipolytica, a protein exhibiting rhodanese (thiosulfate:cyanide sulfurtransferase) activity is associated with proton pumping NADH:ubiquinone oxidoreductase (complex I). Complex I is a key enzyme of the mitochondrial respiratory chain that contains eight iron-sulfur clusters. From a rhodanese deletion strain, we purified functional complex I that lacked the additional protein but was fully assembled and displayed no functional defects or changes in EPR signature. In contrast to previous suggestions, this indicated that the sulfurtransferase associated with Y. lipolytica complex I is not required for assembly of its iron-sulfur clusters.