Protein Assembly Line Components in Prodigiosin Biosynthesis: Characterization of PigA,G,H,I,J
journal contributionposted on 04.10.2006, 00:00 authored by Sylvie Garneau-Tsodikova, Pieter C. Dorrestein, Neil L. Kelleher, Christopher T. Walsh
The red streptomycete metabolite prodigiosin has a unique tripyrrolic structure with two of the three pyrrolyl moieties in tandem. Five enzymes, PigA,G,H,I, and J, are involved in dipyrrole (rings A and B) formation. We have heterologously expressed and purified from Escherichia coli these five enzymes. At first, pyrrole ring A is formed on the peptidyl carrier protein PigG by one of two possible ways: (i) by action of the adenylation domain PigI that transforms l-proline into l-prolyl-AMP and by the flavoprotein dehydrogenase PigA responsible for the four-electron oxidation reaction; (ii) by loading with the pyrrolyl-2-carboxyl-(S)-pantetheinyl moiety from synthetic pyrrolyl-CoA using the phosphopantetheinyl transferase Sfp. Subsequently, pyrrole ring B is constructed by PigH after the transfer of ring A to the ketosynthase of PigJ. PigH consists of three domains: two acyl carrier proteins (ACPs) and a seryltransferase (SerT). Using HPLC and nanospray-Fourier Transform Mass Spectrometry (nFTMS), we established that all three domains of PigH undergo post-translational modifications and gained insight into the machinery involved in 2,2-dipyrrole biosynthesis.
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PigHflavoprotein dehydrogenase PigAphosphopantetheinyl transferase SfpenzymeHPLCProtein Assembly Line Componentsadenylation domain PigIstreptomycete metabolite prodigiosinpeptidyl carrier protein PigGpyrrolyl moietiesACPacyl carrier proteinsEscherichia colidipyrroletripyrrolic structurepyrrole ringpyrrole ring B