A new tRNA promotes the synthesis of streptomyces antibiotics


Nucleic acid research (2022). DOI: 10.1093/nar/gkac502″ width=”800″ height=”523″/>

Structural and functional analysis of tRNA-Asp-AUC. (A) Predicted structure of SPC6 tRNA-Asp-AUC. Filled circles represent G:C base pairs and open circles represent A/G:U base pairs. (B) Relative expression of eGFP in vegetative hyphae of S. coelicolor strains, each containing an eGFP gene integrated with 0-6 copies of an N-terminal GAT codon (D). Error bars indicate SD, *** means P ≤ 0.001. (C) (i) Fluorescence microscopy, differential interference contrast and fused images of vegetative hyphae of SPC6 and S. coelicolor M145 containing the integrated plasmid pIJRCG encoding a modified eGFP with 6 N-terminal aspartic acid residues translated from repeated GAU codons [D], as shown above hyphal images. Also shown are SPC6 hyphae containing the cloning vector pIJ8660 with an unmodified promoterless copy of eGFP. The strains were cultured for 3 days at their optimal temperatures (30°C for S. coelicolor M145 and 37°C for SPC6). (ii) Microscopy of a representative aerial hypha of S. coelicolor M145 containing pIJRCG, sampled after 6 days of growth. The arrow points to a spore. Bar = 10 µM. (D) Microscopy of a representative vegetative hypha, sampled after 3 days of growth, of S. coelicolor M145 containing the integrated plasmid pIJTCG, in which the SPC6 tRNA-Asp-AUC is co-expressed, as shown above the images of hyphae. Bar = 10 µM. Credit: Nucleic acid research (2022). DOI: 10.1093/nar/gkac502

A research team led by Professor Liu Guangxiu from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences (CAS) isolated a fast-growing desert streptomycete in an extreme environment in the Badain Jaran Desert and found a new tRNA-ASP-AUC gene in its genome.

Related results have been published in Nucleic acid research.

Streptomycete is a major group of microorganisms used to synthesize natural products and drugs, and its genome contains a large number of secondary metabolic gene groups.

Although many valuable secondary metabolites, such as streptomycin, natamycin and chloramphenicol, have been identified from various species of streptomycetes and have been used in human clinical treatment, breeding, crop resistance and In other areas, these compounds represent less than 5% of the secondary metabolic gene clusters discovered.

At the same time, many existing fermentation processes have defects such as low antibiotic yield and long cycle. Therefore, how to effectively activate these secondary metabolic gene clusters or improve the fermentation yield of existing antibiotics is essential in the study of microbial antibiotics.

In this study, researchers described the function of a novel tRNA-Asp-AUC found in the SPC6 genome and demonstrated how its heterologous expression both in the model streptomycete, S. coelicolor, and in a range of species of Streptomyces used by the pharmaceutical industry. industry, increased production of antibiotics.

This new tRNA-Asp-AUC gene can not only effectively identify the rare GAT codon of aspartic acid in streptomycetes to promote the expression of secondary metabolic gene groups, but also regulate the synthesis of vitamin B12-related compounds, which is a key factor in antibiotic therapy. synthesis, thus accelerating the synthesis of secondary metabolites and improving their yield.

The study provides an effective scheme to improve the rate of antibiotic synthesis in industrial streptomycetes and opens up an efficient way to develop new secondary metabolites from streptomycetes.

The hidden talent of mushrooms

More information:
Ximing Chen et al, A novel bacterial tRNA enhances antibiotic production in Streptomyces by bypassing inefficient wobble base pairing, Nucleic acid research (2022). DOI: 10.1093/nar/gkac502

Provided by Chinese Academy of Sciences

Quote: Novel tRNA promotes synthesis of streptomyces antibiotics (August 15, 2022) retrieved August 16, 2022 from https://phys.org/news/2022-08-trna-synthesis-streptomyces-antibiotics.html

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