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Cezomycin is activated by CalC to its ester form for further biosynthesis steps in the production of calcimycin in Streptomyces chartreusis NRRL 3882

Wu, H., Liang, J., Wang, J., Liang, W.-J., Gou, L., Wu, Q., Zhou, X., Bruce, Ian J., Deng, Z., Wang, Z. and others. (2018) Cezomycin is activated by CalC to its ester form for further biosynthesis steps in the production of calcimycin in Streptomyces chartreusis NRRL 3882. Applied and Environmental Microbiology, 84 (12). ISSN 0099-2240. (doi:10.1128/AEM.00586-18) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1128/AEM.00586-18

Abstract

Calcimycin, N-demethyl calcimycin, and cezomycin are polyether divalent cation ionophore secondary metabolites produced by Streptomyces chartreusis. A thorough understanding of the organization of their encoding genes, biosynthetic pathway(s), and cation specificities is vitally important for their efficient future production and therapeutic use. So far, this has been lacking, as has information concerning any biosynthetic relationships that may exist between calcimycin and cezomycin. In this study, we observed that when a Cal- (calB1 mutant) derivative of a calcimycin-producing strain of S. chartreusis (NRRL 3882) was grown on cezomycin, calcimycin production was restored. This suggested that calcimycin synthesis may have resulted from postsynthetic modification of cezomycin rather than from a de novo process through a novel and independent biosynthetic mechanism. Systematic screening of a number of Cal- S. chartreusis mutants lacking the ability to convert cezomycin to calcimycin allowed the identification of a gene, provisionally named calC, which was involved in the conversion step. Molecular cloning and heterologous expression of the CalC protein along with its purification to homogeneity and negative-staining electron microscopy allowed the determination of its apparent molecular weight, oligomeric forms in solution, and activity. These experiments allowed us to confirm that the protein possessed ATP pyrophosphatase activity and was capable of ligating coenzyme A (CoA) with cezomycin but not 3-hydroxyanthranilic acid. The CalC protein's apparent Km and kcat for cezomycin were observed to be 190 ?M and 3.98 min-1, respectively, and it possessed the oligomeric form in solution. Our results unequivocally show that cezomycin is postsynthetically modified to calcimycin by the CalC protein through its activation of cezomycin to a CoA ester form.

Item Type: Article
DOI/Identification number: 10.1128/AEM.00586-18
Uncontrolled keywords: Bacteria; Biochemistry; Biosynthesis; Cloning; Esters; Gene therapy; Metabolites; Oligomers; Positive ions; Proteins, Cezomycin; Coa ligase; Heterologous expression; Information concerning; Negative-staining electron microscopy; Postsynthetic modification; Pyrophosphatase activities; Secondary metabolites, Ionophores, biological production; cation; electron microscopy; enzyme; enzyme activity; ester; ether; gene; gene expression; homogeneity; polymer; secondary metabolite; substrate, Streptomyces chartreusis
Subjects: Q Science > QR Microbiology
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: I. Bruce
Date Deposited: 01 Feb 2019 13:12 UTC
Last Modified: 09 Sep 2019 12:15 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/71927 (The current URI for this page, for reference purposes)
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