Participates in cysteine desulfurization mediated by NFS2. Can activate the cysteine desulfurase activity of NFS2 in vitro. Cysteine desulfurization mobilizes sulfur from L-cysteine to yield L-alanine and supplies the inorganic sulfur for iron-sulfur (Fe-S) cluster formation. Cofactor biosynthesis; iron-sulfur cluster biosynthesis. Highly expressed in flowers and pollen, and at low levels in roots, leaves and stems. Belongs to the SufE family.