@misc{9236430,
  abstract     = {{Tuberculosis and nontuberculous mycobacterial infections remain a major global health challenge due to rising antimicrobial resistance, prolonged treatment regimens, and the complex, poorly permeable structure of the mycobacterial cell envelope. This envelope limits antibiotic penetration and contributes to intrinsic drug tolerance. Bacteriophage-derived lytic enzymes, including Lysin A (LysA) and Lysin B (LysB), are emerging as a potential alternative due to their ability to degrade essential components of the mycobacterial cell envelope.
This study evaluated recombinant chimeric enzymes, referred to as mycolysins, containing truncated LysA, full-length LysB, outer membrane permeabilizers (OMPs), protein transduction domains (PTDs) and variable linker sequences. The aim was to assess how truncation and modular construct design affected antimicrobial activity, expression, and solubility. Constructs were expressed in Escherichia coli BL21(DE3), followed by initial screening against Mycobacterium smegmatis using OD600 measurements and resazurin microtiter assays. Selected enzymes were further purified, analysed by SDS-PAGE and tested against pathogenic mycobacteria, including M. tuberculosis H37Ra, M. avium, M. intracellulare and M. abscessus.
Several constructs were successfully expressed, but expression did not consistently result in soluble or active protein after scale-up. Solubility, aggregation during purification, protein loss during desalting and assay interference were major limitations. Activity against M. smegmatis was generally weak after purification, whereas selected constructs showed measurable inhibition against pathogenic mycobacterial strains. Three enzymes exhibited relatively low MIC values against M. tuberculosis H37Ra, ranging from 68 to 137 µg/mL. These results suggest that LysA truncation and chimeric mycolysin design can be compatible with retained antimicrobial activity, but further optimization of expression, purification, stability and quantitative antimicrobial testing is required before therapeutic potential can be reliably assessed.}},
  author       = {{Jamal, Husam Naseer Jamal}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Assessing the effects of domain truncation on the antibacterial activity of endolysins}},
  year         = {{2026}},
}