Oligomer Dynamics of LL‐37 Truncated Fragments Probed by α‐Hemolysin Pore and Molecular Simulations

Abstract

Oligomerization of antimicrobial peptides (AMPs) is critical in their effects on pathogens. LL‐37 and its truncated fragments are widely investigated regarding their structures, antimicrobial activities, and application, such as developing new antibiotics. Due to the small size and weak intermolecular interactions of LL‐37 fragments, it is still elusive to establish the relationship between oligomeric states and antimicrobial activities. Here, an α‐hemolysin nanopore, mass spectrometry (MS), and molecular dynamic (MD) simulations are used to characterize the oligomeric states of two LL‐37 fragments. Nanopore studies provide evidence of trapping events related to the oligomer formation and provide further details on their stabilities, which are confirmed by MS and MD simulations. Furthermore, simulation results reveal the molecular basis of oligomer dynamics and states of LL‐37 fragments. This work provides unique insights into the relationship between the oligomer dynamics of AMPs and their antimicrobial activities at the single‐molecule level. The study demonstrates how integrating methods allows deciphering single molecule level understanding from nanopore sensing approaches.

Pathways of hLL-3717-29 Aggregation Give Insight into the Mechanism of α-Amyloid Formation

“…Intermediate oligomeric states were previously detected in engineered helical peptides aggregating into quasiregular α-helical fibrils . Recent nanopore and mass spectrometry experiments also support the preference of lower-order and intermediate oligomers over higher-order oligomers for two other hLL-37 fragments, which explains the slow kinetics of octamer formation in our case …”

Channel Activities of the Full-Length Prion and Truncated Proteins

“…The thin lipid film was added with pentane (99%, Sigma-Aldrich, Cat number: 236705) to a final concentration of 10 mg/mL. The lipid bilayer was formed followed by the Montal–Mueller technique. , Briefly, a homemade chamber separated by a 25 μm-thick Teflon film (Good Fellow Inc., #FP301200) with a 150 μm aperture was prepared. The aperture was pretreated by 0.5 μL of a 10% ( v / v ) hexadecane/pentane mixture and was dried immediately by N 2 .…”

LL-37: Structures, Antimicrobial Activity, and Influence on Amyloid-Related Diseases

“…Taken together, these NMR and DSC experimental results indicated that a toroidal pore-type membrane disruption is the likely possibility. Mechanisms of membrane interaction and disruption by LL-37 have also been investigated by other approaches [ 86 , 110 , 214 , 231 , 232 , 233 , 234 , 235 , 236 ].…”

“…Taken together, these NMR and DSC experimental results indicated that a toroidal pore-type membrane disruption is the likely possibility. Mechanisms of membrane interaction and disruption by LL-37 have also been investigated by other approaches [86,110,214,[231][232][233][234][235][236]. To investigate the mechanism by which LL-37 perturbs the hydrophobic core of the lipid bilayer, a series of static 2H solid-state NMR and DSC experiments were carried out on lipid vesicles [237].…”