tailieunhanh - Báo cáo khoa học: Erythrochelin – a hydroxamate-type siderophore predicted from the genome of Saccharopolyspora erythraea

The class of nonribosomally assembled siderophores encompasses a multi-tude of structurally diverse natural products. The genome of the erythro-mycin-producing strainSaccharopolyspora erythraeacontains 25 secondary metabolite gene clusters that are mostly considered to be orphan, including two that are responsible for siderophore assembly. | Erythrochelin - a hydroxamate-type siderophore predicted from the genome of Saccharopolyspora erythraea Lars Robbel Thomas A. Knappe Uwe Linne Xiulan Xie and Mohamed A. Marahiel Department of Chemistry Philipps-University Marburg Germany Keywords genome mining nonribosomalpeptide synthetase radiolabeling secondary metabolites siderophore Correspondence M. A. Marahiel Department of Chemistry Philipps-University Marburg D-35043 Marburg Germany Fax 49 0 6421 282 2191 Tel 49 0 6421 282 5722 E-mail marahiel@ Received 4 October 2009 revised 10 November 2009 accepted 23 November 2009 doi The class of nonribosomally assembled siderophores encompasses a multitude of structurally diverse natural products. The genome of the erythro-mycin-producing strain Saccharopolyspora erythraea contains 25 secondary metabolite gene clusters that are mostly considered to be orphan including two that are responsible for siderophore assembly. In the present study we report the isolation and structural elucidation of the hydroxamate-type tetrapeptide siderophore erythrochelin the first nonribosomal peptide synthetase-derived natural product of S. erythraea. In an attempt to substitute the traditional activity assay-guided isolation of novel secondary metabolites we have employed a dedicated radio-LC-MS methodology to identify nonribosomal peptides of cryptic gene clusters in the industrially relevant strain. This methodology was based on transcriptome data and adenylation domain specificity prediction and resulted in the detection of a radiolabeled ornithine-inheriting hydroxamate-type siderophore. The improvement of siderophore production enabled the elucidation of the overall structure via NMR and MSn analysis and hydrolysate-derivatization for the determination of the amino acid configuration. The sequence of the tetrapeptide siderophore erythrochelin was determined to be D-a-N-acetyl-S-N-acetyl-S-N-hydroxyornithine-D-serine-cyclo .