6C62

An unexpected vestigial protein complex reveals the evolutionary origins of an s-triazine catabolic enzyme.

Summary for 6C62

• Entry DOI: 10.2210/pdb6c62/pdb
• Descriptor: Biuret hydrolase, AtzG, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: atze; biuret hydrolase; atrazine; cyanuric acid; ser-cisser-lys hydrolase, hydrolase
• Biological source: Pseudomonas sp. (strain ADP); More
• Total number of polymer chains: 4
• Total formula weight: 111299.57

Authors

Peat, T.S.,Esquirol, L.,Wilding, M.,Liu, J.W.,French, N.G.,Hartley, C.J.,Hideki, O.,Easton, C.J.,Newman, J.,Scott, C. (deposition date: 2018-01-17, release date: 2018-03-21, Last modification date: 2023-11-15)

Primary citation

Esquirol, L.,Peat, T.S.,Wilding, M.,Liu, J.W.,French, N.G.,Hartley, C.J.,Onagi, H.,Nebl, T.,Easton, C.J.,Newman, J.,Scott, C.
An unexpected vestigial protein complex reveals the evolutionary origins of ans-triazine catabolic enzyme.
J. Biol. Chem., 293:7880-7891, 2018

PubMed Abstract: Cyanuric acid is a metabolic intermediate of -triazines, such as atrazine (a common herbicide) and melamine (used in resins and plastics). Cyanuric acid is mineralized to ammonia and carbon dioxide by the soil bacterium sp. strain ADP via three hydrolytic enzymes (AtzD, AtzE, and AtzF). Here, we report the purification and biochemical and structural characterization of AtzE. Contrary to previous reports, we found that AtzE is not a biuret amidohydrolase, but instead it catalyzes the hydrolytic deamination of 1-carboxybiuret. X-ray crystal structures of apo AtzE and AtzE bound with the suicide inhibitor phenyl phosphorodiamidate revealed that the AtzE enzyme complex consists of two independent molecules in the asymmetric unit. We also show that AtzE forms an α2β2 heterotetramer with a previously unidentified 68-amino acid-long protein (AtzG) encoded in the cyanuric acid mineralization operon from sp. strain ADP. Moreover, we observed that AtzG is essential for the production of soluble, active AtzE and that this obligate interaction is a vestige of their shared evolutionary origin. We propose that AtzEG was likely recruited into the cyanuric acid-mineralizing pathway from an ancestral glutamine transamidosome that required protein-protein interactions to enforce the exclusion of solvent from the transamidation reaction.

PubMed: 29523689
DOI: 10.1074/jbc.RA118.001996

Experimental method

X-RAY DIFFRACTION (1.95 Å)