Reconstitution, characterization, and [2Fe–2S] cluster exchange reactivity of a holo human BOLA3 homodimer

Abstract

A new class of mitochondrial disease has been identified and characterized as Multiple Mitochondrial Dysfunctions Syndrome (MMDS). Four different forms of the disease have each been attributed to point mutations in proteins involved in iron–sulfur (Fe–S) biosynthesis; in particular, MMDS2 has been associated with the protein BOLA3. To date, this protein has been characterized in vitro concerning its ability to form heterodimeric complexes with two putative Fe–S cluster-binding partners: GLRX5 and NFU. However, BOLA3 has yet to be characterized in its own discrete holo form. Herein we describe procedures to isolate and characterize the human holo BOLA3 protein in terms of Fe–S cluster binding and trafficking and demonstrate that human BOLA3 can form a functional homodimer capable of engaging in Fe–S cluster transfer.