Identification and functional characterization of phenylglycine biosynthetic genes involved in pristinamycin biosynthesis in Streptomyces pristinaespiralis

“…Briefly, PaaR serves as a repressor in the expression of paa genes encoding the PAA degradation pathway. Its inactivation results in enhanced paa transcription, which would result in more consumption of PA-CoA, the common intermediate for the L-Phg biosynthetic pathway and PAA catabolic pathway (6,11) (Fig. 1).…”

Section: Discussionmentioning

confidence: 99%

“…PA-CoA is the common intermediate for both the PAA degradation pathway and the L-Phg biosynthetic pathway, as shown in Fig. 1 (6,11).…”

mentioning

confidence: 99%

Involvement of the TetR-Type Regulator PaaR in the Regulation of Pristinamycin I Biosynthesis through an Effect on Precursor Supply in Streptomyces pristinaespiralis

et al. 2015

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Pristinamycin I (PI), produced by Streptomyces pristinaespiralis, is a streptogramin type B antibiotic, which contains two proteinogenic and five aproteinogenic amino acid precursors. PI is coproduced with pristinamycin II (PII), a member of streptogramin type A antibiotics. The PI biosynthetic gene cluster has been cloned and characterized. However, thus far little is understood about the regulation of PI biosynthesis. In this study, a TetR family regulator (encoded by SSDG_03033) was identified as playing a positive role in PI biosynthesis. Its homologue, PaaR, from Corynebacterium glutamicum serves as a transcriptional repressor of the paa genes involved in phenylacetic acid (PAA) catabolism. Herein, we also designated the identified regulator as PaaR. Deletion of paaR led to an approximately 70% decrease in PI production but had little effect on PII biosynthesis. Identical to the function of its homologue from C. glutamicum, PaaR is also involved in the suppression of paa expression. Given that phenylacetyl coenzyme A (PA-CoA) is the common intermediate of the PAA catabolic pathway and the biosynthetic pathway of L-phenylglycine (L-Phg), the last amino acid precursor for PI biosynthesis, we proposed that derepression of the transcription of paa genes in a ⌬paaR mutant possibly diverts more PA-CoA to the PAA catabolic pathway, thereby with less PA-CoA metabolic flux toward L-Phg formation, thus resulting in lower PI titers. This hypothesis was verified by the observations that PI production of a ⌬paaR mutant was restored by L-Phg supplementation as well as by deletion of the paaABCDE operon in the ⌬paaR mutant. Altogether, this study provides new insights into the regulation of PI biosynthesis by S. pristinaespiralis. IMPORTANCEA better understanding of the regulation mechanisms for antibiotic biosynthesis will provide valuable clues for Streptomyces strain improvement. Herein, a TetR family regulator PaaR, which serves as the repressor of the transcription of paa genes involved in phenylacetic acid (PAA) catabolism, was identified as playing a positive role in the regulation of pristinamycin I (PI) by affecting the supply of one of seven amino acid precursors, L-phenylglycine, in Streptomyces pristinaespiralis. To our knowledge, this is the first report describing the interplay between PAA catabolism and antibiotic biosynthesis in Streptomyces strains. Considering that the PAA catabolic pathway and its regulation by PaaR are widespread in antibiotic-producing actinomycetes, it could be suggested that PaaR-dependent regulation of antibiotic biosynthesis might commonly exist. P ristinamycin I (PI), produced by Streptomyces pristinaespiralis, is a branched cyclohexadepsipeptide antibiotic and belongs to the B group of streptogramins. PI is coproduced with pristinamycin II (PII), a polyunsaturated cyclopeptidic macrolactone antibiotic, which is a member of the A group of streptogramin antibiotics (1, 2). Two substances are produced in a 30:70 ratio and show a potent synergistic effect with an approximate...

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“…Five aproteinogenic amino acids (3-hydroxypicolinic acid, d-aminobutyric acid, 4-N,N-dimethylamino-N-methyl-l-phenylalanine (DMAPA), 4-oxol-pipecolic acid, and l-phenylglycine) and two proteinogenic amino acids (l-threonine and l-proline) serve as precursors (de Crécy-Lagard et al, 1997;Mast et al, 2011b) (Fig. 1).…”

Section: Streptogramin B Biosynthesis (Pi Vs)mentioning

confidence: 99%

Streptogramins – Two are better than one!

Mast

Wohlleben

2014

International Journal of Medical Microbiology

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Identification and functional characterization of phenylglycine biosynthetic genes involved in pristinamycin biosynthesis in Streptomyces pristinaespiralis

Cited by 33 publications

References 28 publications

A Novel N,N-8-Amino-8-demethyl-d-riboflavin Dimethyltransferase (RosA) Catalyzing the Two Terminal Steps of Roseoflavin Biosynthesis in Streptomyces davawensis

A Novel N,N-8-Amino-8-demethyl-d-riboflavin Dimethyltransferase (RosA) Catalyzing the Two Terminal Steps of Roseoflavin Biosynthesis in Streptomyces davawensis

Involvement of the TetR-Type Regulator PaaR in the Regulation of Pristinamycin I Biosynthesis through an Effect on Precursor Supply in Streptomyces pristinaespiralis

Streptogramins – Two are better than one!

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