scholarly journals Isosteric substitution in cationic-amphiphilic polymers reveals an important role for hydrogen bonding in bacterial membrane interactions

2016 ◽  
Vol 7 (7) ◽  
pp. 4613-4623 ◽  
Author(s):  
D. S. S. M. Uppu ◽  
M. M. Konai ◽  
U. Baul ◽  
P. Singh ◽  
T. K. Siersma ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Amphiphilic Polymers ◽  
Bacterial Membrane ◽  
Membrane Interactions ◽  
Bacterial Membranes

The important role of hydrogen bonding in the interactions of cationic-amphiphilic polymers with bacterial membranes has been reported.

scholarly journals Hexapeptide Derivatives of Glycopeptide Antibiotics: Tools for Mechanism of Action Studies

2002 ◽  
Vol 46 (8) ◽  
pp. 2344-2348 ◽  
Author(s):  
Norris E. Allen ◽  
Deborah L. LeTourneau ◽  
Joe N. Hobbs ◽  
Richard C. Thompson
Keyword(s):  
Micrococcus Luteus ◽  
Membrane Vesicles ◽  
Antibacterial Activities ◽  
Mechanisms Of Action ◽  
Side Chain ◽  
Bacterial Membrane ◽  
Glycopeptide Antibiotics ◽  
Bacterial Membranes ◽  
Derivatives Of

ABSTRACT Hexapeptide (des-N-methylleucyl) derivatives of LY264826 were prepared in order to examine further the role of N-substituted hydrophobic side chains in defining the mechanisms of action of semisynthetic glycopeptide antibiotics. The hexapeptide of LY264826 binds to the cell wall intermediate analog l-Lys-d-Ala-d-Ala with a 100-fold lower affinity than LY264826 and inhibits Micrococcus luteus almost 200-fold more poorly than LY264826 does. Alkylation of the 4-epi-vancosamine moiety of the disaccharide significantly enhanced the antibacterial activity of the hexapeptide. Alkylation did not affect the binding affinity for d-alanyl-d-alanine residues; however, it did enhance dimerization 7,000-fold and enhanced binding to bacterial membrane vesicles noticeably compared with the levels of dimerization and binding for the unsubstituted hexapeptide. The findings from this study complement those presented in an earlier report (N. E. Allen, D. L. LeTourneau, and J. N. Hobbs, Jr., J. Antibiot. 50:677-684, 1997) and are consistent with the conclusion that the enhanced antibacterial activities of semisynthetic glycopeptide antibiotics derive from the ability of the hydrophobic side chain to markedly affect both dimerization and binding to bacterial membranes.

An antimicrobial peptide with an aggregation-induced emission (AIE) luminogen for studying bacterial membrane interactions and antibacterial actions

2017 ◽  
Vol 53 (23) ◽  
pp. 3315-3318 ◽  
Author(s):  
Ning Ning Li ◽  
Jun Zhi Li ◽  
Peng Liu ◽  
Dicky Pranantyo ◽  
Lei Luo ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Bacterial Membrane ◽  
Fluorescence Technique ◽  
Membrane Interactions ◽  
Aggregation Induced Emission ◽  
Bacterial Membranes

A fluorescence technique to investigate the interactions between bacterial membranes and an AIE luminogen-decorated antimicrobial peptide has been reported.

scholarly journals Deciphering the Role of π-Interactions in Polyelectrolyte Complexes Using Rationally Designed Peptides

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon
Keyword(s):  
Hydrogen Bonding ◽  
Phase Separation ◽  
Liquid Phase ◽  
Charge Density ◽  
Secondary Structures ◽  
Liquid Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Π Interactions ◽  
Liquid Liquid Phase Separation

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.

scholarly journals On the Wireless Microwave Sensing of Bacterial Membrane Potential in Microfluidic-Actuated Platforms

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3420
Author(s):  
Marc Jofre ◽  
Lluís Jofre ◽  
Luis Jofre-Roca
Keyword(s):  
Membrane Potential ◽  
Living Cells ◽  
Membrane Potentials ◽  
Electromagnetic Properties ◽  
Bacterial Membrane ◽  
Microfluidic Platforms ◽  
Bacterial Membranes ◽  
Wireless Monitoring ◽  
Bacterial Dynamics ◽  
Engineered Systems

The investigation of the electromagnetic properties of biological particles in microfluidic platforms may enable microwave wireless monitoring and interaction with the functional activity of microorganisms. Of high relevance are the action and membrane potentials as they are some of the most important parameters of living cells. In particular, the complex mechanisms of a cell’s action potential are comparable to the dynamics of bacterial membranes, and consequently focusing on the latter provides a simplified framework for advancing the current techniques and knowledge of general bacterial dynamics. In this work, we provide a theoretical analysis and experimental results on the microwave detection of microorganisms within a microfluidic-based platform for sensing the membrane potential of bacteria. The results further advance the state of microwave bacteria sensing and microfluidic control and their implications for measuring and interacting with cells and their membrane potentials, which is of great importance for developing new biotechnologically engineered systems and solutions.

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...

The role of hydrogen bonding on tuning hard-soft segments in bio-based thermoplastic poly(ether-urethane)s

2020 ◽  
Vol 274 ◽  
pp. 122678
Author(s):  
Paulina Kasprzyk ◽  
Hynek Benes ◽  
Ricardo Keitel Donato ◽  
Janusz Datta
Keyword(s):  
Hydrogen Bonding ◽  
Soft Segments
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