Fig. 1From: Heterologous expression and antitumor activity analysis of syringolin from Pseudomonas syringae pv. syringae B728aThe structure of syringolin. The ring structure consists of two non-proteinogenic amino acids, namely, 3,4-dehydrolysine and 5-methyl-4-amino-2-hexenoic acid. The α-amino group of the latter attaches to valine through a peptide bond, which in turn, is linked to a second valine residue via an unusual ureido groupBack to article page