Single-stranded DNA-binding protein that associates with mitochondrial DNA and may play a role in the regulation of the gene expression machinery. Seems also to be required to prevent break-induced DNA rearrangements in the mitochondrial genome. Can bind to melt double-stranded DNA in vivo. Homotetramer. No visible phenotype under normal growth conditions. Plants over-expressing WHY2 are small with dark-green distorted leaves, exhibit early senescence and produces shorter siliques with half the amount of seeds found in wild-type plants. Belongs to the Whirly family. Truncated N-terminus.