Exciting Advances in Antibiotic Research
Steven Rutherford, a microbial sciences expert at Genentech, expressed enthusiasm about a recent study, describing it as “an exciting advance in efforts to restock the antibiotic arsenal.” He noted in a commentary piece in Nature that the findings illustrate how genome mining can unveil new antibacterial natural products and strategies for their application.
The newly identified megacluster’s products target the biotin synthesis pathway—biotin, or vitamin B7, plays a crucial role in the growth and virulence of numerous human pathogens. It’s more than just a nutrient; it acts as a cofactor essential for the proper functioning of key metabolic enzymes. While some bacteria can absorb biotin from their environment, it’s typically limited, leading many to have pathways that genetically conserve its production.
Interestingly, Brown and his team discovered this biotin-targeting megacluster within Streptomyces species, which are extensively researched. Known as promising sources for antibiotic molecules, these soil-dwelling bacteria have yielded many natural products, including the vital antibiotic streptomycin, which was found in the 1940s. Despite their potential, this particular megacluster had gone unnoticed until now, likely due to lab bacteria often being grown in nutrient-rich environments.
A New Approach
Typically, when seeking new antibiotics in bacterial genomes, researchers look for biosynthetic gene clusters (BGCs) that could produce individual molecules. However, Brown’s team identified a cluster composed of four distinct clusters—the megacluster—that does not just produce one but four molecules that disrupt the biotin pathway in various ways. Their thorough investigation revealed that three of the clusters create antibiotic molecules—stravidins, acidomycins, and dapamycins—that each inhibit a specific enzyme involved in biotin biosynthesis. The fourth cluster, on the other hand, generates 2-methyl-7-keto-8-aminopelargonic acid, or α-Me-KAPA, which seems to act as a dummy molecule, substituting for a biotin precursor and effectively hijacking the pathway to yield a non-functional biotin analog.
