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

The Hitchhiker's guide to biocatalysis: recent advances in the use of enzymes in organic synthesis

“…These enzymes can also catalyse non-natural synthetic reactions, and enzymes are even evolving in vivo to specically handle non-natural industrial chemicals. 1 Moreover, biocatalysts can all function in the same readily available green solvent, water, a capability that the chemical industry needs to attain if it is to be sustainable. 2 In this article we look at how the organic chemist can obtain these niy catalysts, what they do and how they work, and how they can be adapted to industrial use, integrated into chemical processes, and modied to meet specic process requirements.…”

Old enzymes versus new herbicides

“…Instead, they discovered that AtzE deaminates 1-carboxybiuret to produce 1,3-dicarboxyurea and ammonia (Fig. 1B, top panel) (2). Unexpectedly, AtzE co-purified with a 7.4-kDa protein, the product of a previously neglected gene in the atrazine catabolism operon that they named AtzG.…”

“…The authors solved the crystal structure of the AtzE⅐AtzG complex (2). Interestingly, AtzE and AtzG share sequence and structure homology with the ancient, bacterial proteins GatA and GatC, respectively, suggesting an origin for their evolution.…”

“…1B). AtzE also shows substrate promiscuity, as it is capable of hydrolyzing 1-carboxymalonamide, 1-nitrobiuret, and succinamic acid (2).…”

“…Most of the atrazine degradation enzymes encoded in pADP1 have been characterized, with the notable exception of AtzE, which proved recalcitrant to heterologous expression and purification for in vitro studies. The predominating hypothesis was that AtzE would be a biuret amidohydrolase (BiuH), 2 catalyzing the conversion of biuret to allophanate during atrazine degradation (Fig. 1A).…”