Dehydroalanines in goadsporin are proposed to be formed by GodF and GodG, which show slight homology to the N-terminal glutamylation and C-terminal elimination domains, respectively, of LanB, a class I lanthipeptide dehydratase. Although similar, separated-type LanBs are conserved among thiopeptides and indispensable for their biosynthesis and biological activities, these enzymes had not yet been characterized. Here, we identified goadsporin B, which has unmodified Ser4 and Ser14, from both godF and godG disruptants. The godG disruptant also produced goadsporin C, a glutamylated-Ser4 variant of goadsporin B. These results suggested that dehydroalanines are formed by glutamylation and glutamate elimination. NMR analysis revealed for the first time that the glutamyl group was attached to a serine via an ester bond, by the catalysis of LanB-type enzymes. Our findings provide insights into the function of separated-type LanBs involved in the biosynthesis of goadsporin and thiopeptides.
The back cover picture shows a paper disk diffusion assay of goadsporin against Streptomyces lividans TK23 on an agar plate. Through the inactivation of godF and godG, goadsporin B and goadsporin C were identified. The structures of these compounds provide insights into the mechanism of dehydroamino acid formation catalyzed by LanB‐type enzymes. More information can be found in the communication by H. Onaka et al. on page 218 in Issue 3, 2016 (DOI: 10.1002/cbic.201500541).
:In calligraphy, calligraphers express their emotions in calligraphic characters and that impress people who view the characters. Calligraphers generally acquire tacit techniques for expressing emotions by themselves and, therefore, the knowledge on the technique is difficult to be shared. We experimentally studied features of calligraphic characters expressing five different emotions, using writings created by an expert calligrapher. We classified fundamental strokes comprising the characters based on stroking methods defined in 'Eijihappo' and then extracted knowledge on emotion expression techniques in drawing strokes.
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