A S‐adenosylmethionine methyltransferase‐like domain within the essential, Fe‐S‐containing yeast protein Dre2

Yeast Dre2 is an essential Fe‐S cluster‐containing protein that has been implicated in cytosolic Fe‐S protein biogenesis and in cell death regulation in response to oxidative stress. Its absence in yeast can be complemented by the human homologous antiapoptotic protein cytokine‐induced apoptosis inhibitor 1 (also known as anamorsin), suggesting at least one common function. Using complementary techniques, we have investigated the biochemical and biophysical properties of Dre2. We show that it contains an N‐terminal domain whose structure in solution consists of a stable well‐structured monomer with an overall typical S‐adenosylmethionine methyltransferase fold lacking two α‐helices and a β‐strand. The highly conserved C‐terminus of Dre2, containing two Fe‐S clusters, influences the flexibility of the N‐terminal domain. We discuss the hypotheses that the activity of the N‐terminal domain could be modulated by the redox activity of Fe‐S clusters containing the C‐terminus domain in vivo. Database Structural data have been deposited in the Protein Data Bank under accession number 2KM1. Dre2 is a protein essential for yeast viability and the structure in solution of its N‐terminal region was determined by NMR. Itconsists of a stable well‐structured monomer with anoverall typical S‐adenosylmethionine(SAM) methyltransferase fold that however lacks twoα‐helices and aβ‐strand. The highly conserved C‐terminus of Dre2, containing two Fe‐S clusters,influences the flexibility of the N‐terminal domain.