The Interplay between a Multifunctional Dehydratase Domain and a C-Methyltransferase Effects Olefin Shift in Ambruticin Biosynthesis.
The olefin shift is an important modification during polyketide biosynthesis. Particularly for type I cis-AT PKS, little information has been gained on the enzymatic mechanisms involved. We present our in vitro investigations on the olefin shift occurring during ambruticin biosynthesis. The unique, multifunctional domain AmbDH4 catalyzes consecutive dehydration, epimerization, and enoyl isomerization. The resulting 3-enethioate is removed from the equilibrium by α-methylation catalyzed by the highly specific C-methyltransferase AmbM. This thermodynamically unfavorable overall process is enabled by the high, concerted substrate specificity of the involved enzymes. AmbDH4 shows close relationship to DH domains and initial mechanistic studies suggest that the olefin shift occurs via a similar proton-shuttling mechanism as previously described for EI domains from trans-AT-PKS.
Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95447, Bayreuth, Germany.|Zentrum für Biomolekulare Wirkstoffe, Leibniz Universität Hannover, Schneiderberg 38, 30167, Hannover, Germany.
Gesche
G
Berkhan
Ruhr Universität Bochum, Organische Chemie 2, Universitätsstrasse 150, 44801, Bochum, Germany.
Christian
C
Merten
Institut für Bioorganische Chemie, Heinrich-Heine-Universität Düsseldorf im Forschungszentrum Jülich, Stetternicher Forst, Geb. 15.8, 52426, Jülich, Germany.
Claudia
C
Holec
Professur für Organische Chemie (Lebensmittelchemie), Fakultät für Biologie, Chemie und Geowissenschaften, Universität Bayreuth, Universitätsstrasse 30, 95447, Bayreuth, Germany. frank.hahn@oci.uni-hannover.de.|Zentrum für Biomolekulare Wirkstoffe, Leibniz Universität Hannover, Schneiderberg 38, 30167, Hannover, Germany. frank.hahn@oci.uni-hannover.de.
Frank
0000-0002-0603-3482
F
Hahn
D000475:Alkenes / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D006836:Hydro-Lyases / Q000737:chemistry / Q000378:metabolism*; D008780:Methyltransferases / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D011714:Pyrans / Q000737:chemistry / Q000378:metabolism
D000475:Alkenes; D011714:Pyrans; D008780:Methyltransferases; D006836:Hydro-Lyases; C014964:ambruticin
biosynthesis; dehydratases; enoyl isomerases; methyltransferases; polyketides