Pseudomonas sp. strain ADP1 has the ability to mineralise the highly persistent herbicide atrazine. This catabolic pathway involves six or seven enzymes. Recently we characterised biochemically and structurally AtzE (fifth enzyme of the degradation pathway).
Contrary to previous reports, AtzE is not a biuret amidohydrolase, but instead catalyses the hydrolytic deamination of 1-carboxybiuret. Structural characterisation of AtzE showed it is a heterodimer with a previously unidentified 68 amino acid protein (AtzG) encoded in the cyanuric acid mineralization operon. AtzG is essential for the production of soluble active AtzE. We also identified another previously unidentified small protein, AtzH, which is also involved in this catabolic pathway. We have preliminary data that suggesting that this enzyme performs an essential, but unexpected, catalytic function.