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Molecular characterization of the safracin biosynthetic pathway from Pseudomonas fluorescens A2‐2: designing new cytotoxic compounds
Author(s) -
Velasco Ana,
Acebo Paloma,
Gomez Alicia,
Schleissner Carmen,
Rodríguez Pilar,
Aparicio Tomas,
Conde Susana,
Muñoz Rosario,
De La Calle Fernando,
Garcia Jose Luis,
SánchezPuelles Jose M
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04433.x
Subject(s) - biology , operon , gene cluster , pseudomonas fluorescens , orfs , gene , heterologous expression , biochemistry , open reading frame , amino acid , genetics , peptide sequence , escherichia coli , bacteria , recombinant dna
Summary Safracin is an antibiotic with anti‐tumour activity produced by Pseudomonas fluorescens A2‐2. The entire safracin synthetic gene cluster spanning 17.5 kb has been identified, cloned and sequenced. The safracin cluster comprises 10 open reading frames (ORFs) encoding proteins for three non‐ribosomal peptide synthetases (NRPS), three safracin precursor biosynthetic enzymes, two safracin tailoring enzymes, a safracin resistance protein and a small hypothetical protein of unknown function. These genes are organized in two divergent operons of eight and two genes respectively. This pathway exhibits unusual features when compared with other NRPS systems. We have demonstrated by heterologous expression of the cluster that it is able to direct the synthesis of safracin in other strains. Cross‐feeding experiments have confirmed that 3‐hydroxy‐5‐methyl‐ O ‐methyltyrosine is the precursor of two amino acids of the molecule. Genetic analyses have allowed us to demonstrate that the bicistronic operon encodes the hydroxylation and N‐methylation activities of the pathway. The cloning and expression of the safracin cluster has settled the basis for the in vivo and in vitro production of a wide variety of compounds, such as the promising ecteinascidins anti‐cancer compounds.