Molecular dynamics simulations of human α-defensin 5 (HD5) crossing gram-negative bacterial membrane
Issued Date
2023-11-01
Resource Type
eISSN
19326203
Scopus ID
2-s2.0-85177775015
Pubmed ID
37988380
Journal Title
PLoS ONE
Volume
18
Issue
11 November
Rights Holder(s)
SCOPUS
Bibliographic Citation
PLoS ONE Vol.18 No.11 November (2023)
Suggested Citation
Awang T., Chairatana P., Pongprayoon P. Molecular dynamics simulations of human α-defensin 5 (HD5) crossing gram-negative bacterial membrane. PLoS ONE Vol.18 No.11 November (2023). doi:10.1371/journal.pone.0294041 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/91320
Title
Molecular dynamics simulations of human α-defensin 5 (HD5) crossing gram-negative bacterial membrane
Author(s)
Author's Affiliation
Other Contributor(s)
Abstract
Human α-defensin 5 (HD5) is a cationic antimicrobial peptide exhibiting a wide range of antimicrobial activities. It plays an important role in mucosal immunity of the small intestine. HD5 exerts its bactericidal activities through multiple mechanisms, one of which involves HD5 inducing the formation of pores in the bacterial membrane, subsequently allowing the peptide to enter the bacterial cytoplasm. Nevertheless, the precise molecular intricacies underlying its bactericidal mechanisms remain inadequately understood. In this work, the Potential of Mean Force (PMF) was computed to delve into the energetic properties governing the movement of HD5 across the lipopolysaccharide (LPS) membrane, which is a representative model of the gram-negative bacterial membrane. Our findings indicate that the most favorable free energy is attained when HD5 binds to the surface of the LPS membrane. This favorable interaction is primarily driven by the strong interactions between arginine residues in HD5 and the charged head groups of LPS, serving as the predominant forces facilitating the adhesion of HD5 to the membrane. Our analysis reveals that a dimeric form of HD5 alone is sufficient to create a water-filled channel in the membrane; however, achieving the complete lysis of the gram-negative bacterial membrane requires higher-order oligomerization of HD5. Our results suggest that HD5 employs the toroidal pore formation mechanism to disrupt the integrity of the LPS membrane. Furthermore, we identified that the primary energy barrier obstructing HD5 from traversing the membrane is localized within the hydrophobic core of the membrane, which is also observed for other defensins. Additionally, our study demonstrates that a mixture of HD5-LPS leads to a thinning of the membrane. Taken together, this work provides a deeper insight into the molecular intricacies governing the behavior of HD5 as it translocates through the gram-negative bacterial membrane.