FIGURE 3. Proposed mechanism of AdmF compared with prototypical ketosynthase (KS) domains in PKS and condensation (C) domains in NRPS.
From the following article:
A transglutaminase homologue as a condensation catalyst in antibiotic assembly lines
Pascal D. Fortin, Christopher T. Walsh & Nathan A. Magarvey
Nature 448, 824-827(16 August 2007)
doi:10.1038/nature06068
Top left panel, during PK biosynthesis, the KS domain catalyses a claisen condensation to form a C–C bond and proceeds through an acyl-enzyme intermediate. Top right panel, during NRP biosynthesis, the C domain forms C–N bonds and does not proceed through an acyl-enzyme intermediate. Bottom panel, the transglutaminase homologue (TGH)-catalysed condensation proceeds through an acyl-enzyme intermediate and yields a C–N bond.