Identification of the Azaserine Biosynthetic Gene Cluster Implicates Hydrazine as an Intermediate to the Diazo Moiety.

Azaserine () is a natural product and nonproteinogenic amino acid containing a diazo group. Here we report the biosynthetic gene cluster for from . We then use isotopic feeding, gene deletion, and biochemical experiments to support a pathway whereby hydrazinoacetic acid () and a peptidyl carrier protein-loaded serine () are intermediates on route to the final natural product .

Free Piperazic Acid as a Precursor to Nonribosomal Peptides.

Piperazic acid (Piz) is a nonproteinogenic amino acid possessing a rare nitrogen-nitrogen bond. However, little is known about how Piz is incorporated into nonribosomal peptides, including whether adenylation domains specific to Piz exist. In this study, we show that free piperazic acid is directly adenylated and then incorporated into the incarnatapeptin nonribosomal peptides through isotopic incorporation studies.