A5040136367- Nanopore and Nanochannel Transport Studies
- Lipid Membrane Structure and Behavior
- RNA and protein synthesis mechanisms
- Bacterial Genetics and Biotechnology
- Antimicrobial Peptides and Activities
- Microfluidic and Capillary Electrophoresis Applications
- Advanced biosensing and bioanalysis techniques
- Clostridium difficile and Clostridium perfringens research
- Bacteriophages and microbial interactions
- Antibiotic Resistance in Bacteria
- Antibiotics Pharmacokinetics and Efficacy
- ATP Synthase and ATPases Research
- Supramolecular Self-Assembly in Materials
- Chemical Synthesis and Analysis
- Ion channel regulation and function
- RNA Interference and Gene Delivery
- Mitochondrial Function and Pathology
- Genomics and Phylogenetic Studies
- Aquaculture disease management and microbiota
- Electrochemical Analysis and Applications
- Membrane Separation Technologies
- Protein Structure and Dynamics
- Studies on Chitinases and Chitosanases
- Microfluidic and Bio-sensing Technologies
- Force Microscopy Techniques and Applications
Rajiv Gandhi Centre for Biotechnology
2018-2025
University of Oxford
2014-2021
Interdisciplinary Scientific Research
2019
Constructor University
2009-2014
Yokogawa Electric (Japan)
2013
Universidade do Porto
2010
Istituto Officina dei Materiali
2010
The molecular pathway of enrofloxacin, a fluoroquinolone antibiotic, through the outer membrane channel OmpF Escherichia coli is investigated. High-resolution ion current fluctuation analysis reveals strong affinity for enrofloxacin to OmpF, highest value ever recorded an antibiotic-channel interaction. A single point mutation in constriction zone replacing aspartic acid at 113 position with asparagine (D113N), lowers level comparable other antibiotics. All-atom dynamics simulations allow...
Background Multi-drug resistant (MDR) infections have become a major concern in hospitals worldwide. This study investigates membrane translocation, which is the first step required for drug action on internal bacterial targets. β-lactams, antibiotic class, use porins to pass through outer barrier of Gram-negative bacteria. Clinical reports linked MDR phenotype altered permeability including porin modification and efflux pump expression. Methodology/Principal Findings Here influx β-lactams...
A chip-based automated patch-clamp technique provides an attractive biophysical tool to quantify solute permeation through membrane channels. Proteo-giant unilamellar vesicles (proteo-GUVs) were used form a stable lipid bilayer across micrometer-sized hole. Because of the small size and hence low capacitance bilayer, single-channel recordings achieved with very background noise. The latter allowed characterization influx 2 major classes antibiotics-cephalosporins fluoroquinolones-through...
We characterize the rate-limiting interaction of antibiotic enrofloxacin with OmpF, a channel from outer cell wall Escherichia coli . Reconstitution single OmpF trimer into planar lipid membranes allows measurement ion current through channel. Penetration antibiotics causes blockages, and their frequency conclusion on kinetics entry exit. In contrast to other antibiotics, is able block for several milliseconds, reflecting high affinities comparable substrate-specific channels such as...
We investigated translocation of cationic peptides through nanochannels derived from the Gram-positive bacterium Nocardia farcinica at single-molecule level. The two subunits NfpA and NfpB form a hetero-oligomeric cation selective channel. On basis amino acid comparison we performed homology modeling obtained channel structurally related to MspA Mycobacterium smegmatis. quantitative measurements provide an insight into transport processes solutes nanochannels. High-resolution ion conductance...
Background Chitin is the most abundant biopolymer in marine ecosystems. However, there no accumulation of chitin ocean-floor sediments, since bacteria Vibrios are mainly responsible for a rapid turnover biomaterials. The catabolic pathway by multi-step process that involves attachment and degradation, followed chitooligosaccharide uptake across bacterial membranes, catabolism transport products to fructose-6-phosphate, acetate NH3. Principal Findings This study reports isolation gene...
The porinACj is an α-helical porin that spans the mycolic acid outer membrane of Gram-positive mycolate, Corynebacterium jeikeium. Here, we report a 40-amino acid, synthetic peptide, pPorA corresponding to PorACj, inserts into lipid bilayers and forms well-defined pores. By electrical recordings, measured single-channel properties revealed autonomous assembly large conductance ion-selective Further, characterized functional by blocking peptide pores cyclodextrins different charge symmetry....
Membrane pores are exploited for the stochastic sensing of various analytes, and here, we use electrical recordings to explore interaction PEGylated peptides different sizes with a protein pore, CymA. This wide-diameter natural pore comprises densely filled charged residues, facilitating electrophoretic binding polyethylene glycol (PEG) tagged nonaarginine peptide. The small PEG 200 peptide conjugates produced monodisperse blockages exhibited voltage-dependent translocation across pores....
An integrative approach combining biophysical and microbiological methods was used to characterize the antibiotic translocation through outer membrane of Providencia stuartii. Two novel members General Bacterial Porin family Enterobacteriaceae, named OmpPst1 OmpPst2, were identified in P. In presence ertapenem (ERT), cefepime (FEP), cefoxitin (FOX) growth media, several resistant derivatives stuartii ATCC 29914 showed OmpPst1-deficiency. These porin-deficient strains significant decrease...
Gram-negative bacteria are protected by an outer membrane barrier, and to reach their periplasmic target, penicillins have diffuse through porins such as OmpF. Here we propose a structure-dynamics-based strategy for improving antibiotic uptake. Using variety of experiments (high-resolution single channel recording, Minimum Inhibitory Concentration (MIC), liposome swelling assay) accelerated molecular simulations, decipher the subtle balance interactions governing ampicillin diffusion porin...
Chitoporin (VhChiP) is a sugar-specific channel responsible for the transport of chitooligosaccharides through outer membrane marine bacterium Vibrio harveyi. Single reconstitution into black lipid allowed single chitosugar binding events in to be resolved. VhChiP has an exceptionally high substrate affinity, with constant K = 5.0 × 106 m−1 its best (chitohexaose). The on-rates chitosugars depend on applied voltages, as well side sugar addition, clearly indicating inherent asymmetry lumen....
We developed a new, simple and robust approach for rapid screening of single molecule interactions with protein channels. Our glass nanopipets can be fabricated simply by drawing capillaries in standard pipet puller, matter minutes, do not require further modification before use. Giant unilamellar vesicles break when contact the tip form supported bilayer typical seal resistances ∼140 GΩ, which is stable hours at applied potentials up to 900 mV. Bilayers formed, broken, re-formed more than...
Despite advances in peptide and protein design, the rational design of membrane-spanning peptides that form conducting channels remains challenging due to our imperfect understanding sequence-to-structure relationships drive membrane insertion, assembly, conductance. Here, we describe computational experimental characterization a series coiled coil-based transmembrane α-helical barrels with conductive channels. Through combination obtain 5 7 helices, as characterized detergent micelles. In...
Abstract Bacterial porins are essential for molecule transport, yet their functionality in pathogens remains underexplored. Here, a monomeric porin CymAKp is identified and characterized from pathogen Klebsiella pneumoniae , featuring specialized constricted segment (1‐25 residues) the pore. Single‐channel recordings reveal formation of fluctuating nanopores that exhibit gating symmetrical asymmetrical lipid bilayers. The movement drives these events, deletion this results stable...
The role of major porin OmpPst1 Providencia stuartii in antibiotic susceptibility for two carbapenems is investigated by combining high-resolution conductance measurements, liposome swelling, and microbiological assays. Reconstitution a single into planar lipid bilayer measuring the ion current, presence imipenem, revealed concentration-dependent decrease conductance, whereas meropenem produced well-resolved short current blockages. Liposome swelling assays suggested small flux imipenem...
The temperature-dependent transport of the ionic liquid 1-butyl-3-methyl-imidazolium chloride (BMIM-Cl) in aqueous solution is studied theoretically and experimentally. Using molecular dynamics simulations ion-conductance measurements, examined bulk as well through a biological nanopore, that is, OmpF its mutant D113A. This investigation motivated by observation solutions BMIM-Cl drastically reduce translocation speed DNA or antibiotics nanopores electrophysiological measurements. makes an...
ABSTRACT A striking characteristic of mycobacteria is the presence an unusual outer membrane which forms a thick permeability barrier and provides resistance to many antibiotics. Although specialized proteins must reside in this layer, only few mycolate (MOM) have been identified date. Their discovery complicated by difficulties obtaining good separation mycobacterial inner membranes. During our efforts identify novel (MOMPs), we discovered that can enrich for MOMPs using differential...