Kamikaze termites protect their colony with the help of a special enzyme

The termite species Neocapritermes taracua has evolved a peculiar defence mechanism that is unparalleled in the insect world. Worker termites play a key role in it. Over their lifetime, they gradually amass a particular enzyme, blue laccase BP76, in special pockets on their backs. When their colony finds itself in danger, older individuals tear this ‘rucksack’ apart. The enzyme is then almost immediately mixed with another substance stored in the termite body, which up to this point is relatively harmless, creating a sticky liquid containing highly poisonous benzoquinones. Although this kills the kamikaze termite itself, it also immobilizes or kills the attacker.

How this potentially explosive enzyme stays active in a solid state on the backs of insects was a true scientific riddle. Scientists from the Structural Biology research group at IOCB Prague have solved the puzzle with the help of X-ray crystallography. Jana Škerlová was intrigued by the fact that the blue laccase borne by termites contains an unusually strong bond between two amino acids—which are the building blocks of proteins—near the active site of the enzyme, to which the target molecule binds and where it reacts. She explains: ‘Unravelling the three-dimensional structure of laccase BP76 revealed that this enzyme uses a variety of stabilization strategies, which make it not only highly durable, but also fully functional even in the harsh conditions of tropical rainforests.’ Due to its unique structure, laccase BP76 not only remains intact, but also active even though it rests on the back of a termite over the course of its entire life. This is crucial for the enzyme’s role in the defence mechanism, because in the event of an attack on the colony, the reaction must be immediate.

Read the full press release here.