An alginate-like exopolysaccharide biosynthesis gene cluster involved in biofilm aerial structure formation by Pseudomonas alkylphenolia

ABSTRACTThe pyrrole polyether antibiotic calcimycin (A23187) is a rare ionophore that is specific for divalent cations. It is widely used as a biochemical and pharmacological tool because of its multiple, unique biological effects. Here we report on the cloning, sequencing, and mutational analysis of the 64-kb biosynthetic gene cluster fromStreptomyces chartreusisNRRL 3882. Gene replacements confirmed the identity of the gene cluster, andin silicoanalysis of the DNA sequence revealed 27 potential genes, including 3 genes for the biosynthesis of the α-ketopyrrole moiety, 5 genes that encode modular type I polyketide synthases for the biosynthesis of the spiroketal ring, 4 genes for the biosynthesis of 3-hydroxyanthranilic acid, anN-methyltransferase tailoring gene, a resistance gene, a type II thioesterase gene, 3 regulatory genes, 4 genes with other functions, and 5 genes of unknown function. We propose a pathway for the biosynthesis of calcimycin and assign the genes to the biosynthesis steps. Our findings set the stage for producing much desired calcimycin derivatives using genetic modification instead of chemical synthesis.

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Enhancement of the Diversity of Polyoxins by a Thymine-7-Hydroxylase Homolog outside the Polyoxin Biosynthesis Gene Cluster

Applied and Environmental Microbiology ◽

10.1128/aem.01257-10 ◽

2010 ◽

Vol 76 (21) ◽

pp. 7343-7347 ◽

Cited By ~ 12

Author(s):

Changming Zhao ◽

Tingting Huang ◽

Wenqing Chen ◽

Zixin Deng

Keyword(s):

Gene Cluster ◽

Carbon Skeleton ◽

Open Reading Frame ◽

Streptomyces Avermitilis ◽

Biosynthesis Gene Cluster ◽

Reading Frame ◽

Biosynthesis Gene ◽

Pyrimidine Moiety

ABSTRACT Polyoxins consist of 14 structurally variable components which differentiate at three branch sites of the carbon skeleton. Open reading frame (ORF) SAV_4805 of Streptomyces avermitilis, showing similarity to thymine-7-hydroxylase, was proved to enhance the diversity of polyoxins at the C-5 site of the 1-(5′-amino-5′-deoxy-β-d-allofuranuronosyl) pyrimidine moiety.

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Characterization of the Amicetin Biosynthesis Gene Cluster from Streptomyces vinaceusdrappus NRRL 2363 Implicates Two Alternative Strategies for Amide Bond Formation

Applied and Environmental Microbiology ◽

10.1128/aem.07185-11 ◽

2012 ◽

Vol 78 (7) ◽

pp. 2393-2401 ◽

Cited By ~ 30

Author(s):

Gaiyun Zhang ◽

Haibo Zhang ◽

Sumei Li ◽

Ji Xiao ◽

Guangtao Zhang ◽

...

Keyword(s):

Gene Cluster ◽

Acyl Carrier Protein ◽

Bond Formation ◽

Antiviral Agent ◽

Amide Bond ◽

Biosynthesis Gene Cluster ◽

Alternative Strategies ◽

Content Type ◽

Amide Bond Formation ◽

Biosynthesis Gene

ABSTRACTAmicetin, an antibacterial and antiviral agent, belongs to a group of disaccharide nucleoside antibiotics featuring an α-(1→4)-glycoside bond in the disaccharide moiety. In this study, the amicetin biosynthesis gene cluster was cloned fromStreptomyces vinaceusdrappusNRRL 2363 and localized on a 37-kb contiguous DNA region. Heterologous expression of the amicetin biosynthesis gene cluster inStreptomyces lividansTK64 resulted in the production of amicetin and its analogues, thereby confirming the identity of theamigene cluster.In silicosequence analysis revealed that 21 genes were putatively involved in amicetin biosynthesis, including 3 for regulation and transportation, 10 for disaccharide biosynthesis, and 8 for the formation of the amicetin skeleton by the linkage of cytosine,p-aminobenzoic acid (PABA), and the terminal (+)-α-methylserine moieties. The inactivation of the benzoate coenzyme A (benzoate-CoA) ligase geneamiLand theN-acetyltransferase geneamiFled to two mutants that accumulated the same two compounds, cytosamine and 4-acetamido-3-hydroxybenzoic acid. These data indicated that AmiF functioned as an amide synthethase to link cytosine and PABA. The inactivation ofamiR, encoding an acyl-CoA-acyl carrier protein transacylase, resulted in the production of plicacetin and norplicacetin, indicating AmiR to be responsible for attachment of the terminal methylserine moiety to form another amide bond. These findings implicated two alternative strategies for amide bond formation in amicetin biosynthesis.

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