(a) Sequence alignment of the Whirly domains of mitochondria-directed Whirlies. AtWhy2, Arabidopsis WHY2; StWhy2, S. tuberosum WHY2. (b) Structural alignment of mitochondria-directed Whirly proteins in cartoon representation with WHY2 in yellow and potato WHY2 (PDB entry 3n1h
) in light blue. The black arrows point to the β-hairpin encompassing residues 74–90.