Neither Touches the Food

They grew the halves seven days at twenty. Each folded like a trap: two lobes, a cleft between.

An amino acid drops in. The lobes close. That closing is the signal.

Two pairs of side chains reach across the gap and hook — one near the bound molecule, one further out. Neither touches the food.

L-alanine held about eleven times tighter than its mirror. The mirror still made a small answer. Swap those hooks for the human versions and the fish turned picky.

Looking stops on the hooks that do not grab and still keep the trap shut.