The mtaA gene of the myxothiazol biosynthetic gene cluster from Stigmatella aurantiaca DW4/3-1 encodes a phosphopantetheinyl transferase that activates polyketide synthases and polypeptide synthetases.
Myxothiazol is synthesized by the myxobacterium Stigmatella aurantiaca DW4/3-1 via a combined polyketide synthase/polypeptide synthetase. The biosynthesis of this secondary metabolite is also dependent on the gene product of mtaA. The deduced amino acid sequence of mtaA shows similarity to 4'-phosphopantetheinyl transferases (4'-PP transferase). This points to an enzyme activity that converts inactive forms of the acyl carrier protein domains of polyketide synthetases (PKSs) and/or the peptidyl carrier protein domains of nonribosomal polypeptide synthetases (NRPSs) of the myxothiazol synthetase complex to their corresponding holo-forms. Heterologous co-expression of MtaA with an acyl carrier protein domain of the myxothiazol synthetase was performed in Escherichia coli. The proposed function as a 4'-PP transferase was confirmed and emphasizes the significance of MtaA for the formation of a catalytically active myxothiazol synthetase complex. Additionally, it is shown that MtaA has a relaxed substrate specificity: it processes an aryl carrier protein domain derived from the enterobactin synthetase of E. coli (ArCP) as well as a peptidyl carrier protein domain from a polypeptide synthetase of yet unknown function from Sorangium cellulosum. Therefore, MtaA should be a useful tool for activating heterologously expressed PKS and NRPS systems.
Gaitatzis
N
N
German Research Centre for Biotechnology, Mascheroder Weg D-38124 Braunschweig, Germany.
Hans
A
A
Müller
R
R
Beyer
S
S
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004789:Enzyme Activation; D015964:Gene Expression Regulation, Bacterial; D008689:Methacrylates; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism*; D005810:Multigene Family; D010453:Peptide Synthases / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020606:Stigmatella aurantiaca / Q000201:enzymology / Q000235:genetics*; D013379:Substrate Specificity; D013844:Thiazoles / Q000378:metabolism*; D017855:Transferases (Other Substituted Phosphate Groups)
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008689:Methacrylates; D009097:Multienzyme Complexes; D013844:Thiazoles; C082662:phosphopantetheinyl transferase; C030517:myxothiazol; D017855:Transferases (Other Substituted Phosphate Groups); D000251:Adenosine Triphosphatases; D010453:Peptide Synthases