Ochratoxin A (OTA) is a neurotoxic, genotoxic, carcinogenic, and teratogenic mycotoxin that contaminates foods for human consumption. We have found an α/β hydrolase capable of hydrolyzing it, which has been analyzed.

Ochratoxin A (OTA) is a highly neurotoxic, immunosuppressive, genotoxic, carcinogenic, and teratogenic mycotoxin that contaminates foods for human consumption, mainly cereals and derivatives, alcoholic beverages, and milled products (coffee, cocoa), which poses serious health problems. There are strains of the genus Acinetobacter that hydrolyze the amide bond of OTA producing OTα and L-β-phenylalanine that are not toxic; in particular, the carboxypeptidase PJ15_1540 from Acinetobacter sp. neg1 has been identified as an enzyme that degrades OTA. In this work, we describe the ability to hydrolyze OTA from protein extracts of Acinetobacter tandoii DSM 14970T, a strain isolated from sludge plants, as well as the discovery of a new and promiscuous α/β hydrolase (ABH), with highly close homologs highly distributed in the genus Acinetobacter. ABH from A. tandoii (AtABH) has amidase activity against the mycotoxins OTA and OTB, as well as against several carboxypeptidase-type substrates. The predicted structure of AtABH reveals an α/β hydrolase core composed of a six-stranded parallel β-sheet, with a cap domain similar to that present in the marine esterase EprEst. Additional biochemical analyses of AtABH reveal that it is an efficient esterase with a specificity profile similar to that of EprEst. Molecular docking studies have allowed us to propose a binding mode for OTA. We propose a possible procedure to design new OTA-degrading enzymes from promiscuous α/β hydrolases. Ana Sánchez‑Arroyo, Laura Plaza‑Vinuesa, María Claudia Abeijón‑Mukdsi, Blanca de las Rivas, José Miguel Mancheño, Rosario Muñoz. A new and promiscuous α/β hydrolase from Acinetobacter tandoii DSM 14970T inactivates the mycotoxin ochratoxin A. Appl Microbiol Biotechnol 2024; 108(1): 230. doi: 10.1007/s00253-024-13073-x.