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

Related results were published in Nucleic Acids 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 clusters. 

Although many valuable secondary metabolites, such as streptomycin, natamycin and chloramphenicol, have been identified from a variety of streptomycete species, and have been used in human clinical treatment, animal breeding, crop resistance and other fields, these compounds account for less than 5% of the discovered secondary metabolic gene clusters. 

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 the key in the study of microbial antibiotics. 

In this study, the 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 Streptomyces species used by the pharmaceutical industry, increased production of antibiotics. 

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

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

Contact: 

LIU Guangxiu 

E-mail: liugx@lzb.ac.cn