Fig. 2.

HRMS analysis of ¹⁴N-incorporation into ¹⁵N-labeled fosfazinomycin A. a Fosfazinomycin A produced by Streptomyces sp. NRRL S-149 cultivated in uniformly ¹⁵N-labeled medium. The calculated m/z ([M+H]⁺) for uniformly ¹⁵N-labeled fosfazinomycin A is 461.1966. b, c Spectra from cells cultivated in uniformly ¹⁵N-labeled media and fed with either (b) NaNO₂ or (c) N-hydroxyaspartic acid (2). The calculated m/z ([M+H]⁺) for fosfazinomycin A with a single ¹⁴N atom is 460.1996. d, e Spectra from cells grown in uniformly ¹⁵N-labeled media and fed with either d hydrazinosuccinic acid (3), or e acetylhydrazine. The calculated m/z ([M+H]⁺) for ¹⁵N-fosfazinomycin A with two ¹⁴N atoms is 459.2025