Manipulation and Structural Activity of AcpM in Mycobacterium tuberculosis

Area of Science:

• Biochemistry
• Molecular Biology
• Microbiology

Background:

• Mycobacterium tuberculosis (Mtb) causes significant mortality, with rising drug resistance linked to cell wall mycolic acids.
• Type II fatty acid biosynthesis (FAS-II) is essential for mycolic acid production.
• Acyl carrier protein M (AcpM) regulates protein-protein interactions (PPIs) in FAS-II, but its unique features complicate study.

Purpose of the Study:

• To develop a streamlined method for generating homogeneous, modified AcpM samples for biophysical studies.
• To investigate the role of AcpM in FAS-II enzyme interactions and substrate regulation.
• To understand AcpM's contribution to Mtb pathogenicity and drug resistance.

Main Methods:

• A chemo-enzymatic strategy was employed to synthesize modified AcpM analogs.
• Solvatochromic labeling was used to create crypto-AcpM for fluorescence-based assays.
• Interactions between modified AcpM and four FAS-II enzymes were monitored using fluorescence.

Main Results:

• Homogeneous samples of modified AcpM were successfully generated.
• Fluorescence response indicated cargo sequestration and chain flipping upon AcpM interaction with FAS-II enzymes.
• A truncated form, AcpM80, showed increased fluorescence, suggesting the C-terminus modulates the chemical environment and regulates PPIs.

Conclusions:

• The developed chemo-enzymatic strategy provides efficient access to AcpM analogs for biophysical characterization.
• Understanding AcpM's regulatory role in FAS-II is critical for deciphering Mtb pathogenicity.
• This research aids in developing new strategies against drug-resistant tuberculosis.