Pristinamycin I biosynthesis in Streptomyces pristinaespiralis: molecular characterization of the first two structural peptide synthetase genes
Two genes involved in the biosynthesis of the depsipeptide antibiotics pristinamycins I (PI) produced by Streptomyces pristinaespiralis were cloned and sequenced. The 1.7-kb snbA gene encodes a 3-hydroxypicolinic acid: AMP ligase, and the 7.7-kb snbC gene encodes PI synthetase 2, responsible for incorporating L-threonine and L-aminobutyric acid in the PI macrocycle. snbA and snbC, which encode the two first structural enzymes of PI synthesis, are not contiguous. Both genes are located in PI-specific transcriptional units, as disruption of one gene or the other led to PI-deficient strains producing normal levels of the polyunsaturated macrolactone antibiotic pristinamycin II, also produced by S. pristinaespiralis. Analysis of the deduced amino acid sequences showed that the SnbA protein is a member of the adenylate-forming enzyme superfamily and that the SnbC protein contains two amino acid-incorporating modules and a C-terminal epimerization domain. A model for the initiation of PI synthesis analogous to the established model of initiation of fatty acid synthesis is proposed.
| Main Authors: | , , , , , , , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | L50 - Physiologie et biochimie animales, antibiotique, gène, Clonage moléculaire, biosynthèse, http://aims.fao.org/aos/agrovoc/c_492, http://aims.fao.org/aos/agrovoc/c_3214, http://aims.fao.org/aos/agrovoc/c_27503, http://aims.fao.org/aos/agrovoc/c_928, |
| Online Access: | http://agritrop.cirad.fr/507703/ http://agritrop.cirad.fr/507703/1/507703.pdf |
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