Antimycobacterial Rufomycin Analogues from Streptomyces atratus Strain MJM3502

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Microbiology

Background:

• The rise of drug-resistant Mycobacterium tuberculosis (TB) necessitates novel therapeutic strategies.
• The caseinolytic protein C1 (ClpC1) is a potential new target for anti-TB drug discovery.
• Cyclic heptapeptides (RUFs) have emerged as a promising class of compounds.

Purpose of the Study:

• To conduct a systematic chemical and biological investigation of the rufomycin (RUF) class of cyclic heptapeptides.
• To identify and characterize novel RUF analogues with potential anti-TB activity.
• To evaluate the efficacy and selectivity of RUFs against key mycobacterial pathogens.

Main Methods:

• Isolation and characterization of eight new RUF analogues (rufomycins NBZ1-NBZ8) and five known peptides from *Streptomyces atratus*.
• Determination of absolute configurations using advanced Marfey's analysis and X-ray crystallography.
• Biological evaluation of isolated compounds against *M. tuberculosis* H37Rv and *M. abscessus*.

Main Results:

• Eight novel rufomycin analogues (1-8) and five known peptides (9-13) were successfully isolated and characterized.
• The absolute configurations of the rufomycins were definitively assigned.
• Several rufomycin isolates demonstrated potent antimicrobial activity against both *M. tuberculosis* and *M. abscessus*.
• High selectivity indices (selectivity index >60) were observed for active isolates.

Conclusions:

• Rufomycins represent a promising class of natural products with significant potential as anti-TB drug leads.
• The identified RUF analogues exhibit potent activity against clinically relevant mycobacterial species.
• Targeting ClpC1 with rufomycins offers a novel therapeutic avenue for combating TB and related infections.