Poster Presentation The 43rd Lorne Conference on Protein Structure and Function 2018

Unexpected role for newly identified small proteins in atrazine mineralisation (#126)

Lygie Esquirol 1 2 , Thomas TSP Peat 3 , Matthew MW Wilding 1 3 , Jian-Wei JWL Liu 2 , Nigel NGF French 2 , Carol CJH Hartley 2 , Hideki HO Onagi 1 , Christopher CJE Easton 1 , Janet JN Newman 3 , Colin CS Scott 2
  1. Research School of Chemistry, ANU, Acton, ACT, Australia
  2. Biocatalysis and Synthetic Biology, CSIRO, Acton, ACT, Australia
  3. Biomedical manufacturing, CSIRO, Parkville, VIC, Australia

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.