scholarly journals Small molecules enhance the potency of natural antimicrobial peptides

2021 ◽  
Author(s):  
Valeria Losasso ◽  
Khushbu Agarwal ◽  
Morris Waskar ◽  
Amitabha Majumdar ◽  
Jason Crain ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Physical Properties ◽  
Well Being ◽  
Head Group ◽  
Bacterial Membrane ◽  
Vitamin B3 ◽  
Detailed Chemistry ◽  
Dynamics Simulations ◽  
Skin Care Products ◽  
Fine Tune

The skin-associated microbiome plays an important role in general well-being and in a variety of treatable conditions. In this regard, endogenous antimicrobial peptides have a role in controlling the microbial population. We demonstrate here that certain small molecular species can amplify the potency of naturally-occurring antimicrobial peptides. For example, Niacinamide is a vitamin B3 analogue naturally found in foods and widely used in topical skin care products, and here we have investigated its cooperativity with the human antimicrobial peptide LL37 on the bacterium Staphylococcus aureus. We have also studied two other structurally related B3 analogs. We observed a clear synergistic effect of niacinamide and, to some extent, methyl niacinamide, whereas isonicotinamide showed no significant cooperativity with LL37. Adaptively-biased molecular dynamics simulations revealed that the analogs partition into the head group region of an anionic bilayer used to mimic the bacterial membrane. The observed effects on the physical properties of the membrane are well correlated with experimental activity. In contrast, the analogs have little effect on zwitterionic bilayers which mimic a mammalian membrane. We conclude that these vitamin B3 analogues can potentiate the activity of host peptides by modulating the physical properties of the bacterial membrane, and to a lesser extent through direct interactions with the peptide. The level of cooperativity is strongly dependent on the detailed chemistry of the additive, suggesting an opportunity to fine-tune the behaviour of host peptides.

scholarly journals Structural characterization of the antimicrobial peptides myxinidin and WMR in bacterial membrane mimetic micelles and bicelles

2021 ◽  
Author(s):  
Yevhen K. Cherniavskyi ◽  
Rosario Oliva ◽  
Marco Stellato ◽  
Pompea Del Vecchio ◽  
Stefania Galdiero ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Antimicrobial Peptides ◽  
Molecular Dynamics Simulations ◽  
Lipid Bilayers ◽  
Structural Characterization ◽  
Bacterial Membrane ◽  
Membrane Composition ◽  
Membrane Mimetic ◽  
Dynamics Simulations

Antimicrobial peptides are a promising class of alternative antibiotics that interact selectively with negatively charged lipid bilayers. This paper presents the structural characterization of the antimicrobial peptides myxinidin and WMR associated with bacterial membrane mimetic micelles and bicelles by NMR, CD spectroscopy, and Molecular Dynamics simulations. Both peptides adopt a different conformation in the lipidic environment than in aqueous solution. The location of peptides in micelles and bicelles has been studied by paramagnetic relaxation enhancement experiments with paramagnetic tagged 5- and 16-doxyl stearic acid (5-/16-SASL). Multi-microsecond long molecular dynamics simulations of multiple copies of the peptides were used to gain an atomic level of detail on membrane-peptide and peptide-peptide interactions. Our results highlight an essential role of the negatively charged membrane mimetic in the structural stability of both myxinidin and WMR. The peptides localize predominantly in the membrane's headgroup region and have a noticeable membrane thinning effect on the overall bilayer structure. Myxinidin and WMR show different tendency to self-aggregate, which is also influenced by the membrane composition (DOPE/DOPG versus DOPE/DOPG/CL) and can be related to the previously observed difference in the ability of the peptides to disrupt different types of model membranes.

scholarly journals Towards designing globular antimicrobial peptide mimics: role of polar functional groups in biomimetic ternary antimicrobial polymers

Soft Matter ◽  
2021 ◽  
Author(s):  
Garima Rani ◽  
Kenichi Kuroda ◽  
Satyavani Vemparala
Keyword(s):  
Molecular Dynamics ◽  
Antimicrobial Peptide ◽  
Bacterial Membrane ◽  
Simulation Data ◽  
Antimicrobial Polymers ◽  
Polar Groups ◽  
Methacrylate Polymers ◽  
Dynamics Simulations ◽  
Polar Functional Groups

Using atomistic molecular dynamics simulations, we study the interaction of ternary methacrylate polymers, composed of charged cationic, hydrophobic and neutral polar groups, with model bacterial membrane. Our simulation data shows...

scholarly journals Molecular dynamics simulations and experimental studies reveal differential permeability of withaferin-A and withanone across the model cell membrane

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Renu Wadhwa ◽  
Neetu Singh Yadav ◽  
Shashank P. Katiyar ◽  
Tomoko Yaguchi ◽  
Chohee Lee ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Cell Membrane ◽  
Molecular Dynamics Simulations ◽  
Experimental Studies ◽  
Bilayer Membrane ◽  
Withaferin A ◽  
Head Group ◽  
Polar Head Group ◽  
Natural Drugs ◽  
Dynamics Simulations

AbstractPoor bioavailability due to the inability to cross the cell membrane is one of the major reasons for the failure of a drug in clinical trials. We have used molecular dynamics simulations to predict the membrane permeability of natural drugs—withanolides (withaferin-A and withanone) that have similar structures but remarkably differ in their cytotoxicity. We found that whereas withaferin-A, could proficiently transverse through the model membrane, withanone showed weak permeability. The free energy profiles for the interaction of withanolides with the model bilayer membrane revealed that whereas the polar head group of the membrane caused high resistance for the passage of withanone, the interior of the membrane behaves similarly for both withanolides. The solvation analysis further revealed that the high solvation of terminal O5 oxygen of withaferin-A was the major driving force for its high permeability; it interacted with the phosphate group of the membrane that led to its smooth passage across the bilayer. The computational predictions were tested by raising and recruiting unique antibodies that react to withaferin-A and withanone. The time-lapsed analyses of control and treated cells demonstrated higher permeation of withaferin-A as compared to withanone. The concurrence between the computation and experimental results thus re-emphasised the use of computational methods for predicting permeability and hence bioavailability of natural drug compounds in the drug development process.

scholarly journals Crystal structure of a YeeE/YedE family protein engaged in thiosulfate uptake

2020 ◽  
Vol 6 (35) ◽  
pp. eaba7637
Author(s):  
Yoshiki Tanaka ◽  
Kunihito Yoshikaie ◽  
Azusa Takeuchi ◽  
Muneyoshi Ichikawa ◽  
Tomoyuki Mori ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Sulfur Cycle ◽  
Sulfur Source ◽  
Bacterial Membrane ◽  
Density Maps ◽  
Family Protein ◽  
Cysteine Synthesis ◽  
Plausible Mechanism ◽  
Dynamics Simulations ◽  
Positively Charged

We have demonstrated that a bacterial membrane protein, YeeE, mediates thiosulfate uptake. Thiosulfate is used for cysteine synthesis in bacteria as an inorganic sulfur source in the global biological sulfur cycle. The crystal structure of YeeE at 2.5-Å resolution reveals an unprecedented hourglass-like architecture with thiosulfate in the positively charged outer concave side. YeeE is composed of loops and 13 helices including 9 transmembrane α helices, most of which show an intramolecular pseudo 222 symmetry. Four characteristic loops are buried toward the center of YeeE and form its central region surrounded by the nine helices. Additional electron density maps and successive molecular dynamics simulations imply that thiosulfate can remain temporally at several positions in the proposed pathway. We propose a plausible mechanism of thiosulfate uptake via three important conserved cysteine residues of the loops along the pathway.

Antimicrobial peptides of the genus Bacillus: a new era for antibiotics

2015 ◽  
Vol 61 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Chandra Datta Sumi ◽  
Byung Wook Yang ◽  
In-Cheol Yeo ◽  
Young Tae Hahm
Keyword(s):  
Antimicrobial Peptides ◽  
Well Being ◽  
Rapid Onset ◽  
Antibacterial Drug ◽  
Genus Bacillus ◽  
Antimicrobial Drugs ◽  
Food Preservatives ◽  
New Era ◽  
Peptide Biosynthesis ◽  
Conventional Antibiotics

The rapid onset of resistance reduces the efficacy of most conventional antimicrobial drugs and is a general cause of concern for human well-being. Thus, there is great demand for a continuous supply of novel antibiotics to combat this problem. Bacteria-derived antimicrobial peptides (AMPs) have long been used as food preservatives; moreover, prior to the development of conventional antibiotics, these AMPs served as an efficient source of antibiotics. Recently, peptides produced by members of the genus Bacillus were shown to have a broad spectrum of antimicrobial activity against pathogenic microbes. Bacillus-derived AMPs can be synthesized both ribosomally and nonribosomally and can be classified according to peptide biosynthesis, structure, and molecular weight. The precise mechanism of action of these AMPs is not yet clear; however, one proposed mechanism is that these AMPs kill bacteria by forming channels in and (or) disrupting the bacterial cell wall. Bacillus-derived AMPs have potential in the pharmaceutical industry, as well as the food and agricultural sectors. Here, we focus on Bacillus-derived AMPs as a novel alternative approach to antibacterial drug development. We also provide an overview of the biosynthesis, mechanisms of action, applications, and effectiveness of different AMPs produced by members of the Bacillus genus, including several recently identified novel AMPs.

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