Territrem B

Territrem B is a tremorgenic fungal mycotoxin isolated from Aspergillus terreus and originally characterized together with territrem A. Biochemical studies demonstrated that territrem B is a potent inhibitor of acetylcholinesterase (AChE) exhibiting noncovalent yet functionally irreversible inhibition with quasi-first-order kinetics and one-to-one stoichiometry. Binding studies and X-ray crystallography revealed that territrem B spans the peripheral (P) site and extends into the acylation (A) site at the base of the active-site gorge, where it becomes tightly trapped within the gorge structure. This unique binding mode explains its high affinity and persistent inhibition distinct from classical covalent organophosphate inhibitors. Immunoelectron microscopy further localized territrem B production to conidia of A. terreus, consistent with its classification as a tremorgenic neurotoxic mycotoxin.