Structural evolution of LEAFY reveals DNA-mediated cooperativity and dimerization shifts at the water-to-land transition.

Crystal structures of the LEAFY DNA-binding domain from Nothoceros aenigmaticus and Interfilum paradoxum show two distinct dimerization mechanisms, including DNA-mediated cooperativity, shifting during the water-to-land transition.

• Why it matters: TF binding specificity evolves to enable regulatory innovation, but LEAFY’s diversification without extensive duplication raises questions about how DNA and dimerization interactions change across major evolutionary transitions.
• What they did: The study combined experimental crystal structure determination with biochemical assays to compare LFY DNA-bound complexes from hornwort and alga, identifying direct protein-protein dimerization versus DNA-mediated cooperativity.
• The result: The ancestral state is linked to DNA-mediated dimer binding, with protein-protein dimerization emerging later to enforce new DNA-binding preferences, supporting a revised evolutionary scenario for LFY binding specificity.

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