Hydrazinoacetic Acid is a Biosynthetic Precursor to N-Nitroglycine

Gabriel Padilla, Ben Rathman, David Graham, Jonathan Caranto

University of Central Florida, Oak Ridge National Laboratories

N-nitroglycine (NNG) is an N–N bond containing natural product produced by Steptomyces noursei. It has a nitramine functional group (R-N(H)NO₂). It was discovered in 1968, and a biosynthetic pathway for it has not been elucidated. Biosynthetic gene cluster prediction of the S. noursei genome by antiSMASH suggests the presence of enzymatic machinery to produce hydrazinoacetic acid (HAA)—another N–N bond containing natural product—from l-lysine and glycine. HAA has been shown to act as a precursor for diverse N–N bond functionalities, including hydrazone and N-hydroxytriazene functionalities. We posited that HAA was also a precursor for NNG. By stable isotope labeling studies, we have shown that lysine, glycine, and HAA are all precursors for NNG. These results support our hypothesis and suggest that we have identified the NNG biosynthetic gene cluster. Genes nearby the HAA-producing machinery encode metalloenzymes, including a heme oxygenase-like diiron oxidase. These proteins have ample precedent for nitrogen oxidation, and it is proposed that this one is also involved in oxidizing HAA to NNG. This presentation will discuss our latest work in understanding NNG biosynthesis.