|Title||alpha,beta -> beta,gamma double bond migration in corallopyronin A biosynthesis|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Lohr F., Jenniches I., Frizler M., Meehan M.J, Sylvester M., Schmitz A., Gutschow M., Dorrestein PC, Konig G.M, Schaberle T.F|
|Type of Article||Article|
|Keywords||actinosynnema-pretiosum; ansamitocin; bacillus-subtilis; carrier domains; gene-cluster; mass-spectrometry; polyketide synthase|
In polyketide biosynthesis the reduction of beta-carbonyl groups to an alkene usually results in a alpha,beta double bond. However, in a few antibiotics the rare case of such a carbon-carbon double bond in beta,gamma position is observed. The in vivo active antibiotic corallopyronin A represents such a molecule, whereby a alpha,beta -> beta,gamma double bond migration takes place during the assembly of the molecule. Here we report the in vitro analysis of the enzyme domain responsible for this double bond isomerization. This "shift domain" was heterologously expressed and assayed with its acyl carrier protein bound substrate. To facilitate this analysis the biosynthetic corallopyronin A intermediate was chemically synthesized as a SNAC-derivative. Enzyme activity was analyzed by NMR and high-resolution MS measurements, the latter enabled by performing the assay in deuterated buffer. Mutated enzyme variants gave first experimental evidence for the essential amino acids involved in double bond migration. These results further support the proposed corallopyronin A biosynthesis.
|Short Title||Chem. Sci.|