title: 4'-phosphopantetheinyl transferase-encoding npgA is essential for siderophore biosynthesis in Aspergillus nidulans.
abstract: Aspergillus nidulans produces two major siderophores: it excretes triacetylfusarinine C to capture iron and contains ferricrocin as an intracellular iron-storage compound. Siderophore biosynthesis involves the enzymatic activity of nonribosomal peptide synthetases (NRPS). NRPS contain 4'-phosphopantetheine as an essential prosthetic group, which is attached by 4'-phosphopantetheinyl transferases. A. nidulans appears to possess at least one gene, npgA, encoding such an enzyme. Using a strain carrying a temperature-sensitive allele, cfwA2, we showed that NpgA is essential for biosynthesis of both the peptide bond-containing ferricrocin and the ester bond-containing triacetylfusarinene C. The cfwA2 strain was found to be iron-starved at the restrictive temperature during iron-replete conditions, consistent with the siderophore system being the major iron-uptake system-as we recently demonstrated. Northern analysis indicated that, in contrast to other genes which are involved in siderophore biosynthesis and uptake, expression of npgA is not controlled by the GATA-transcription factor SreA. It was shown previously that NpgA is required for biosynthesis of penicillin, pigment, and potentially lysine via the alpha-aminoadipate pathway. Supplementation with lysine plus triacetylfusarinine C restored normal growth of the cfwA2 strain at the restrictive temperature, suggesting that the growth defect of the mutant is mainly due to impaired biosynthesis of siderophores and lysine.
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D002851:Chromatography, High Pressure Liquid; D005291:Ferrichrome / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000096:biosynthesis* / Q000737:chemistry; D009841:Oligonucleotides; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis* / Q000737:chemistry; D013696:Temperature; D017855:Transferases (Other Substituted Phosphate Groups) / Q000235:genetics* / Q000378:metabolism
chemical_list: C409889:ARN2 protein, S cerevisiae; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D009841:Oligonucleotides; D029701:Saccharomyces cerevisiae Proteins; C082662:phosphopantetheinyl transferase; D005291:Ferrichrome; C021678:ferricrocin; D007501:Iron; D017855:Transferases (Other Substituted Phosphate Groups)