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Model amphipathic peptide

Dirk van den Brand, Cornelia Veelken, Leon Massuger, Roland Brock
Drug delivery into tumors and metastases is a major challenge in the eradication of cancers such as epithelial ovarian carcinoma. Cationic cell-penetrating peptides (CPPs) are a promising group of delivery vehicles to mediate cellular entry of molecules that otherwise poorly enter cells. However, little is known about their penetration behavior in tissues. Here, we investigated penetration of cationic CPPs in 3D ovarian cancer spheroids and patient-derived 3D tumor explants. Penetration kinetics and distribution after long-term incubation were imaged by confocal microscopy...
March 14, 2018: Biochimica et Biophysica Acta
Philippe A Gallay, Udayan Chatterji, Aaron Kirchhoff, Angel Gandarilla, Richard B Pyles, Marc M Baum, John A Moss
Introduction: In the absence of a vaccine, there is an urgent need for the identification of effective agents that prevent HIV transmission in uninfected individuals. Non-vaccine Biomedical Prevention (nBP) methods, such as topical or systemic pre-exposure prophylaxis (PrEP), are promising strategies to slow down the spread of AIDS. Methods: In this study, we investigated the microbicidal efficacy of the viral membrane-disrupting amphipathic SWLRDIWDWICEVLSDFK peptide called C5A...
2018: Open Virology Journal
Yanhua Ouyang, Likun Zhao, Zhuqing Zhang
Intrinsically disordered regions (IDRs) or proteins (IDPs), which play crucial biological functions in essential biological processes of life, do not have well-defined secondary or tertiary structures when isolated in solution. The highly dynamic properties and conformational heterogeneity of IDPs make them challenging to study with traditional experimental techniques. As a powerful complementary tool for experiments, all-atom molecular dynamics simulation can obtain detailed conformational information on IDPs, but the limitation of force field accuracy is a challenge for reproducing IDP conformers...
March 14, 2018: Physical Chemistry Chemical Physics: PCCP
Juanjuan Su, Ann S Thomas, Tanja Grabietz, Christiane Landgraf, Rudolf Volkmer, Siewert J Marrink, Chris Williams, Manuel N Melo
Pex11p plays a crucial role in peroxisome fission. Previously, it was shown that a conserved N-terminal amphipathic helix in Pex11p, termed Pex11-Amph, was necessary for peroxisomal fission in vivo while in vitro studies revealed that this region alone was sufficient to bring about tubulation of liposomes with a lipid consistency resembling the peroxisomal membrane. However, molecular details of how Pex11-Amph remodels the peroxisomal membrane remain unknown. Here we have combined in silico, in vitro and in vivo approaches to gain insights into the molecular mechanisms underlying Pex11-Amph activity...
March 1, 2018: Biochimica et Biophysica Acta
Matías A Via, Joaquín Klug, Natalia Wilke, Luis S Mayorga, M G Del Pópolo
Cell-penetrating peptides (CPP) are short sequences of cationic amino-acids that show a surprising ability to traverse lipid bilayers. CPP are considered to be some of the most effective vectors to introduce membrane-impermeable cargos into cells, but the molecular basis of the membrane translocation mechanisms and its dependence on relevant membrane physicochemical properties have yet to be fully determined. In this paper we resort to Molecular Dynamics simulations and experiments to investigate how the electrostatic potential across the lipid/water interface affects the insertion of hydrophilic and amphipathic CPP into two-dimensional lipid structures...
February 2, 2018: Physical Chemistry Chemical Physics: PCCP
Mara Kozic, Stephen J Fox, Jens M Thomas, Chandra S Verma, Daniel J Rigden
Antimicrobial resistance within a wide range of infectious agents is a severe and growing public health threat. Antimicrobial peptides (AMPs) are among the leading alternatives to current antibiotics, exhibiting broad spectrum activity. Their activity is determined by numerous properties such as cationic charge, amphipathicity, size and amino acid composition. Currently, only around 10% of known AMP sequences have experimentally solved structures. To improve our understanding of the AMP structural universe we have carried out large scale ab initio 3D modelling of structurally uncharacterised AMPs that revealed similarities between predicted folds of the modelled sequences and structures of characterized AMPs...
February 1, 2018: Proteins
Alex T Müller, Jan A Hiss, Gisbert Schneider
We present a generative long short-term memory (LSTM) recurrent neural network (RNN) for combinatorial de novo peptide design. RNN models capture patterns in sequential data and generate new data instances from the learned context. Amino acid sequences represent a suitable input for these machine-learning models. Generative models trained on peptide sequences could therefore facilitate the design of bespoke peptide libraries. We trained RNNs with LSTM units on pattern recognition of helical antimicrobial peptides and used the resulting model for de novo sequence generation...
January 22, 2018: Journal of Chemical Information and Modeling
Deepthi Poornima Budagavi, Archana Chugh
Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) share certain physicochemical parameters such as amphipathicity, hydrophobicity, cationicity and pI, due to which these two groups of peptides also exhibit overlapping functional characteristics. In our current work, we have evaluated antimicrobial properties of cell-penetrating peptides derived from Latarcin1. Latarcin derived peptide (LDP) exhibited antimicrobial activity against representative microorganisms tested and bactericidal effect against methicillin resistant Staphylococcus aureus (MRSA), which was used as model organism of study in the present work...
January 9, 2018: European Journal of Pharmaceutical Sciences
Victor Spicer, Oleg V Krokhin
Peptide separation selectivity of four different HILIC sorbents was compared through the development of sequence-specific retention prediction algorithms for the datasets of 36-40 thousands peptides each. Hydrophilicity of these sorbents at pH 4.5 (peptide retention under acetonitrile:water gradients) increases in the following order: Luna HILIC < XBridge Amide < Atlantis Silica ∼ Luna HILIC Silica. Bare silica phases are characterized by higher retention coefficients for basic residues (Arg, Lys, His), while interactions with neutral HILIC phases is driven by interaction with the charged residues (Asp, Glu, Arg, Lys, His)...
December 18, 2017: Journal of Chromatography. A
Jonathan B Mandell, Berthony Deslouches, Ronald C Montelaro, Robert M Q Shanks, Yohei Doi, Kenneth L Urish
Antibiotics are unable to remove biofilms from surgical implants. This high antibiotic tolerance is related to bacterial persisters, a sub-population of bacteria phenotypically tolerant to antibiotics secondary to a reduced metabolic state. WLBU2 is an engineered cationic amphipathic peptide designed to maximize antimicrobial activity with minimal mammalian cell toxicity. The objective of this study was to test the ability of WLBU2 to remove Staphylococcus aureus surgical implant biofilms. WLBU2 effectively treated S...
December 22, 2017: Scientific Reports
Imogen M Bermingham, Keith J Chappell, Daniel Watterson, Paul R Young
Respiratory syncytial virus (RSV) mediates host cell entry through the fusion (F) protein, which undergoes a conformational change to facilitate the merger of viral and host lipid membrane envelopes. The RSV F protein comprises a trimer of disulfide-bonded F1 and F2 subunits that is present on the virion surface in a metastable prefusion state. This prefusion form is readily triggered to undergo refolding to bring two heptad repeats (heptad repeat A [HRA] and HRB) into close proximity to form a six-helix bundle that stabilizes the postfusion form and provides the free energy required for membrane fusion...
February 15, 2018: Journal of Virology
Peng Zhang, Jing Ma, Yujie Yan, Bo Chen, Bobo Liu, Cui Jian, Baode Zhu, Songping Liang, Youlin Zeng, Zhonghua Liu
Lycosin-I is a linear amphipathic α-helical anticancer peptide (ACP) extracted from the spider Lycosa singoriensis, which can activate the mitochondrial death pathway to induce apoptosis in tumor cells and up-regulate p27 to inhibit cell proliferation. However, the applicability of lycosin-I as a novel anticancer drug is limited by its low cellular entry and efficacy in solid tumors. Amino acid substitution presents an effective and modest strategy to improve the anticancer activity and bioavailability of ACPs...
November 15, 2017: Organic & Biomolecular Chemistry
Muhammad Zafir Mohamad Nasir, Joshua A Jackman, Nam-Joon Cho, Adriano Ambrosi, Martin Pumera
Detection of infectious viruses and disease biomarkers is of utmost importance in clinical screening for effective identification and treatment of diseases. We demonstrate here the use of liposome rupture impact voltammetry for the qualitative detection of model amphipathic viral peptide on a screen-printed electrode. This novel, proof-of-concept method was proposed for the quick and reliable detection of viruses by nonfaradaic liposome rupture impact voltammetry with the aid of 1,2-dioleoyl-sn-glycero-3-phosphocholine liposomes...
November 7, 2017: Analytical Chemistry
Ting-Wei Chang, Shu-Yi Wei, Shih-Han Wang, Hung-Mu Wei, Yu-June Wang, Chiu-Feng Wang, Chinpan Chen, You-Di Liao
Antimicrobial peptides are important components of the host innate defense mechanism against invading pathogens, especially for drug-resistant bacteria. In addition to bactericidal activity, the 25 residue peptide TP4 isolated from Nile tilapia also stimulates cell proliferation and regulates the innate immune system in mice. In this report, TP4 hyperpolarized and depolarized the membrane potential of Pseudomonas aeruginosa at sub-lethal and lethal concentrations. It also inhibited and eradicated biofilm formation...
2017: PloS One
Shaun Pacheco, Shan-Yu Fung, Mingyao Liu
Self-assembling peptides (SAPs) are promising vehicles for the delivery of hydrophobic therapeutics for clinical applications; their amphipathic properties allow them to dissolve hydrophobic compounds in the aqueous environment of the human body. However, self-assembling peptide solutions have poor blood compatibility (e.g., low osmolarity), hindering their clinical application through intravenous administrations. We have recently developed a generalized platform for hydrophobic drug delivery, which combines SAPs with amino acid solutions (SAP-AA) to enhance drug solubility and increase formulation osmolarity to reach the requirements for clinical uses...
September 20, 2017: Journal of Visualized Experiments: JoVE
Mukesh Mahajan, Deepak Chatterjee, Kannaian Bhuvaneswari, Shubhadra Pillay, Surajit Bhattacharjya
The lethal Coronaviruses (CoVs), Severe Acute Respiratory Syndrome-associated Coronavirus (SARS-CoV) and most recently Middle East Respiratory Syndrome Coronavirus, (MERS-CoV) are serious human health hazard. A successful viral infection requires fusion between virus and host cells carried out by the surface spike glycoprotein or S protein of CoV. Current models propose that the S2 subunit of S protein assembled into a hexameric helical bundle exposing hydrophobic fusogenic peptides or fusion peptides (FPs) for membrane insertion...
February 2018: Biochimica et Biophysica Acta
Luís Vasconcelos, Tõnis Lehto, Fatemeh Madani, Vlad Radoi, Mattias Hällbrink, Vladana Vukojević, Ülo Langel
Peptides able to translocate cell membranes while carrying macromolecular cargo, as cell-penetrating peptides (CPPs), can contribute to the field of drug delivery by enabling the transport of otherwise membrane impermeable molecules. Formation of non-covalent complexes between amphipathic peptides and oligonucleotides is driven by electrostatic and hydrophobic interactions. Here we investigate and quantify the coexistence of distinct molecular species in multiple equilibria, namely peptide monomer, peptide self-aggregates and peptide/oligonucleotide complexes...
February 2018: Biochimica et Biophysica Acta
Oleg Babii, Sergii Afonin, Tim Schober, Igor V Komarov, Anne S Ulrich
For the first time, the photoisomerization of a diarylethene moiety (DAET) in peptide conjugates was used to probe the effects of molecular rigidity/flexibility on the structure and behavior of model peptides bound to lipid membranes. The DAET unit was incorporated into the backbones of linear peptide-based constructs, connecting two amphipathic sequences (derived from the β-stranded peptide (KIGAKI)3 and/or the α-helical peptide BP100). A β-strand-DAET-α-helix and an α-helix-DAET-α-helix models were synthesized and studied in phospholipid membranes...
December 2017: Biochimica et Biophysica Acta
Shih-Yi Peng, Ren-In You, Meng-Jiun Lai, Nien-Tsung Lin, Li-Kuang Chen, Kai-Chih Chang
The increase in the prevalence of multidrug-resistant Acinetobacter baumannii (MDRAB) strains is a serious public health concern. Antimicrobial peptides (AMPs) are a possible solution to this problem. In this study, we examined whether AMPs could be derived from phage endolysins. We synthesized four AMPs based on an amphipathic helical region in the C-terminus of endolysin LysAB2 encoded by the A. baumannii phage ΦAB2. These peptides showed potent antibacterial activity against A. baumannii (minimum inhibitory concentration, 4-64 μM), including some MDR and colistin-resistant A...
September 13, 2017: Scientific Reports
Zhi Ma, Jinzhi Han, Bingxue Chang, Ling Gao, Zhaoxin Lu, Fengxia Lu, Haizhen Zhao, Chong Zhang, Xiaomei Bie
Methicillin-resistant Staphylococcus aureus (MRSA) has become increasingly prevalent in hospitals, clinics, and the community. MRSA can cause significant and even lethal infections, especially in skin burn wounds. The currently available topical agents have largely failed to eliminate MRSA infections due to resistance. Therefore, there is an urgent need for new and effective approaches for treating MRSA. Here, we show that a novel engineered amphipathic peptide, WRL3 (WLRAFRRLVRRLARGLRR-NH2), exhibits potent antimicrobial activity against MRSA, even in the presence of various salts or serum...
September 18, 2017: ACS Infectious Diseases
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