Biosynthesis
How Actinomycetes make specialized metabolites is our central topic. These molecules are very complex and an organic chemist would struggle to make them in the laboratory. What he lacks and what microorganisms have, are unusual enzymes. They choose one or several molecules, which you find in a microbial, but also plant or human cell. However, only the microbial enzymes can take the uninteresting molecule, and transform it step-by-step into something special, complex, and with biological activity. We study these enzymes and how they function and biosynthesize specialized metabolites. Some of the enzymes are worth studying on their own because they have an unexpected function, use unusual cofactors or have novel protein structure. These studies are a prerequisite for our attempt to prepare more efficient antibiotics.
Discovery of New Bioactive Metabolites (untargeted search)
Soil Actinomycetes are a well-known source of bioactive metabolites. In fact, most of currently used antibiotics are from Actinomycetes, including often prescribed lincosamides (clindamycin), macrolides (azithromycin), or last-resort glycopeptides (vancomycin). We aim to discover novel bioactive metabolites – we have assembled a collection of >1 000 Actinomycetes from diverse habitants (soil, sea, etc.). We are using state-of-the art metabolomics combined with a traditional approach of cultivating Actinobacteria in laboratory conditions and with testing their metabolites against our collection of multi-resistant pathogens including those most dangerous ones from Czech hospitals.
Biosynthesis of Lincosamides
Over the last decade, we have succeeded in elucidating several biosynthetic steps from the specialized biosynthetic pathways of anticancer pyrrolobenzodiazepines and lincosamide antibiotics including characterization of several unusual biosynthetic enzymes. For instance, we managed to elucidate the function of F420H2-dependent oxidoreductases, deacetylases from the TldD/TldE family of protein, or a pyridoxal-5-phosphate-dependent lyase. Right now, we are trying to solve the three dimensional structure of reductases, which use an unusual deazaflavin F420 cofactor, to explain their unprecedented ability to reduce two double bonds of their substrate.
Preparation of more Efficient Antibiotics
Furthermore, we take advantage of our knowledge of how lincosamide antibiotics are made. Specifically, we use genetic engineering (eg. CRISPR-Cas 9 technique) to combine the pathways from two different strains. In this way, we prepared a novel natural ´unnatural´ lincosamide chimera consisting of lincomycin and celesticetin structural motives. We named this compound CELIN, tested its bioactivity, turning out to be a more efficient antibiotic compared to other lincosamides. We are now conducting preclinical trials to find out the potential of CELIN to be applied in clinical practice. We also continue to further enhance CELIN efficiency by modifications using organic synthesis.
Institue of Microbiology
Institute of Microbiology, CAS
Vídeňská 1083, 142 20 Prague 4 - Krč
The Czech Republic
BIOCEV
Institute of Microbiology, CAS
Průmyslová 595, 252 50 Vestec
The Czech Republic
Contact Us
lab111@biomed.cas.cz
+420 241 062 508