Figure 3.

Precursor feeding of isotopically labeled aspartate, sodium nitrite, and glycine in production of 3. A) HRMS analysis of 3 from cultures provided with 10 mM ¹⁵N-aspartate, 1 mM sodium ¹⁵N-nitrite, or varying isotopically labeled glycine substrates at 10 mM. B) ¹³C NMR spectra of 3 isolated from cultures of S. aureofaciens supplied with either 10 mM unlabeled glycine or 2-¹³C, ¹⁵N-glycine. Close inspection on the enriched C1 signal shows peak splitting, indicative of an adjacent ¹⁵N, which is not observed in 3 purified from cultures fed unlabeled glycine.