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Model amphipathic peptide

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https://www.readbyqxmd.com/read/29090725/arginine-modification-of-lycosin-i-to-improve-inhibitory-activity-against-cancer-cells
#1
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
https://www.readbyqxmd.com/read/29058893/detection-of-amphipathic-viral-peptide-on-screen-printed-electrodes-by-liposome-rupture-impact-voltammetry
#2
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
https://www.readbyqxmd.com/read/29040295/hydrophobic-residues-are-critical-for-the-helix-forming-hemolytic-and-bactericidal-activities-of-amphipathic-antimicrobial-peptide-tp4
#3
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
https://www.readbyqxmd.com/read/28994806/solubility-of-hydrophobic-compounds-in-aqueous-solution-using-combinations-of-self-assembling-peptide-and-amino-acid
#4
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
https://www.readbyqxmd.com/read/28988778/nmr-structure-and-localization-of-a-large-fragment-of-the-sars-cov-fusion-protein-implications-in-viral-cell-fusion
#5
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...
October 5, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28962904/simultaneous-membrane-interaction-of-amphipathic-peptide-monomers-self-aggregates-and-cargo-complexes-detected-by-fluorescence-correlation-spectroscopy
#6
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...
September 26, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28958778/flexibility-vs-rigidity-of-amphipathic-peptide-conjugates-when-interacting-with-lipid-bilayers
#7
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
https://www.readbyqxmd.com/read/28904355/highly-potent-antimicrobial-modified-peptides-derived-from-the-acinetobacter-baumannii-phage-endolysin-lysab2
#8
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
https://www.readbyqxmd.com/read/28885829/membrane-active-amphipathic-peptide-wrl3-with-in-vitro-antibiofilm-capability-and-in-vivo-efficacy-in-treating-methicillin-resistant-staphylococcus-aureus-burn-wound-infections
#9
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
https://www.readbyqxmd.com/read/28876512/effect-of-stapling-architecture-on-physiochemical-properties-and-cell-permeability-of-stapled-%C3%AE-helical-peptides-a-comparative-study
#10
Yuan Tian, Yanhong Jiang, Jingxu Li, Dongyuan Wang, Hui Zhao, Zigang Li
Stapled peptides have emerged as a new class of targeting molecules with high binding affinity and specificity for intracellular undruggable targets. Their ability to penetrate cell membranes is exceptionally intriguing but remains elusively and controversially discussed. To understand the effect of stapling architectures on their physiochemical properties and to aid in promoting their cell permeability, we report herein a comparative study on the physiochemical properties and cell permeability of stapled α-helical peptides with different types of crosslinks...
September 6, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28867522/do-amyloid-structures-formed-by-staphylococcus-aureus-phenol-soluble-modulins-have-a-biological-function
#11
Yue Zheng, Hwang-Soo Joo, Vinod Nair, Katherine Y Le, Michael Otto
Phenol-soluble modulins (PSMs) are alpha-helical, amphipathic peptides that have multiple functions in staphylococcal physiology and virulence. Recent research has suggested that PSMs form amyloid fibrils and amyloids are involved in PSM-mediated phenotypes such as cytolysis and biofilm stability. While we observed PSM amyloid formation using electron microscopy and dye assays, there were no apparent differences in the production of extracellular fibrous material between a PSM-deficient strain and the isogenic wild-type strain...
September 1, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/28853007/lipid-packing-perturbation-of-model-membranes-by-ph-responsive-antimicrobial-peptides
#12
REVIEW
Dayane S Alvares, Taisa Giordano Viegas, João Ruggiero Neto
The indiscriminate use of conventional antibiotics is leading to an increase in the number of resistant bacterial strains, motivating the search for new compounds to overcome this challenging problem. Antimicrobial peptides, acting only in the lipid phase of membranes without requiring specific membrane receptors as do conventional antibiotics, have shown great potential as possible substituents of these drugs. These peptides are in general rich in basic and hydrophobic residues forming an amphipathic structure when in contact with membranes...
October 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/28798159/as-cath1-6-novel-cathelicidins-with-potent-antimicrobial-and-immunomodulatory-properties-from-alligator-sinensis-play-pivotal-roles-in-host-antimicrobial-immune-responses
#13
Yan Chen, Shasha Cai, Xue Qiao, Mali Wu, Zhilai Guo, Renping Wang, Yi-Qun Kuang, Haining Yu, Yipeng Wang
Crocodilians are regarded as possessing a powerful immune system. However, the composition and action of the crocodilian immune system have remained unclear until now. Cathelicidins, the principal family of host defense peptides, play pivotal roles in vertebrate immune defense against microbial invasions. However, cathelicidins from crocodilians have not been extensively studied to date. In the present study, six novel cathelicidins (As-CATH1-6) were identified and characterized from the endangered Chinese alligator (Alligator sinensis)...
August 10, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28726635/as-cath1-6-novel-cathelicidins-with-potent-antimicrobial-and-immunomodulatory-properties-from-alligator-sinensis-play-pivotal-roles-in-host-anti-microbial-immune-responses
#14
Yan Chen, Shasha Cai, Xue Qiao, Mali Wu, Zhilai Guo, Renping Wang, Yi-Qun Kuang, Haining Yu, Yipeng Wang
Crocodilians are regarded as possessing a powerful immune system. However, the composition and action of crocodilian immune system has remained unclear until now. Cathelicidins, the principal family of host defense peptides, play pivotal roles in vertebrate immune defense against microbial invasions. However, cathelicidins from crocodilians have not been extensively studied to date. In the present study, six novel cathelicidins (As-CATH1~6) were identified and characterized from the endangered Chinese Alligator ( Alligator sinensis )...
July 18, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28583830/probing-the-disparate-effects-of-arginine-and-lysine-residues-on-antimicrobial-peptide-bilayer-association
#15
A Rice, J Wereszczynski
Antimicrobial peptides (AMPs) are key components of the innate immune response and represent promising templates for the development of broad-spectrum alternatives to conventional antibiotics. Most AMPs are short, cationic peptides that interact more strongly with negatively charged prokaryotic membranes than net neutral eukaryotic ones. Both AMPs and synthetic analogues with arginine-like side chains are more active against bacteria than those with lysine-like amine groups, though the atomistic mechanism for this increase in potency remains unclear...
October 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28479275/effect-of-tacticity-derived-topological-constraints-in-bactericidal-peptides
#16
Prakash Kishore Hazam, Gaurav Jerath, Anil Kumar, Nitin Chaudhary, Vibin Ramakrishnan
Topology is a key element in structure-activity relationship estimation while designing physiologically-active molecular constructs. Peptides may be a preferred choice for therapeutics, principally due to their biocompatibility, low toxicity and predictable metabolism. Peptide design only guarantees functional group constitution by opting specific amino acid sequence, and not their spatial orientation to bind and incite physiological response on chosen targets. This is principally because peptide conformation is subject to external flux, due to the isotactic stereochemistry of the peptide chain...
August 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28470277/characterizing-the-structure-function-relationship-reveals-the-mode-of-action-of-a-novel-antimicrobial-peptide-p1-from-jumper-ant-myrmecia-pilosula
#17
Tien-Sheng Tseng, Keng-Chang Tsai, Chinpan Chen
Microbial infections of antibiotic-resistant strains cause serious diseases and have a significant impact on public health worldwide, so novel antimicrobial drugs are urgently needed. Insect venoms, a rich source of bioactive components containing antimicrobial peptides (AMPs), are attractive candidates for new therapeutic agents against microbes. Recently, a novel peptide, P1, identified from the venom of the Australian jumper ant Myrmecia pilosula, showed potent antimicrobial activities against both Gram-negative and Gram-positive bacteria, but its structure-function relationship is unknown...
May 4, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28459565/membrane-disruption-mechanism-of-a-prion-peptide-106-126-investigated-by-atomic-force-microscopy-raman-and-electron-paramagnetic-resonance-spectroscopy
#18
Jianjun Pan, Prasana K Sahoo, Annalisa Dalzini, Zahra Hayati, Chinta M Aryal, Peng Teng, Jianfeng Cai, Humberto Rodriguez Gutierrez, Likai Song
A fragment of the human prion protein spanning residues 106-126 (PrP106-126) recapitulates many essential properties of the disease-causing protein such as amyloidogenicity and cytotoxicity. PrP106-126 has an amphipathic characteristic that resembles many antimicrobial peptides (AMPs). Therefore, the toxic effect of PrP106-126 could arise from a direct association of monomeric peptides with the membrane matrix. Several experimental approaches are employed to scrutinize the impacts of monomeric PrP106-126 on model lipid membranes...
May 10, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28429592/peptide-retention-time-prediction-in-hydrophilic-interaction-liquid-chromatography-data-collection-methods-and-features-of-additive-and-sequence-specific-models
#19
Oleg V Krokhin, Peyman Ezzati, Vic Spicer
The development of a peptide retention prediction model for hydrophilic interaction liquid chromatography (XBridge Amide column) is described for a collection of ∼40 000 tryptic peptides. Off-line 2D LC-MS/MS analysis (HILIC-RPLC) of S. cerevisiae whole cell lysate has been used to acquire retention information for a HILIC separation. The large size of the optimization data set (more than 2 orders of magnitude compared to previous reports) permits the accurate assignment of hydrophilic retention coefficients of individual amino acids, establishing both the effects of amino acid position relative to peptide termini and the influence of peptide secondary structure in HILIC...
April 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28411186/direct-antimicrobial-activity-of-ifn-%C3%AE
#20
Amber Kaplan, Michelle W Lee, Andrea J Wolf, Jose J Limon, Courtney A Becker, Minna Ding, Ramachandran Murali, Ernest Y Lee, George Y Liu, Gerard C L Wong, David M Underhill
Type I IFNs are a cytokine family essential for antiviral defense. More recently, type I IFNs were shown to be important during bacterial infections. In this article, we show that, in addition to known cytokine functions, IFN-β is antimicrobial. Parts of the IFN-β molecular surface (especially helix 4) are cationic and amphipathic, both classic characteristics of antimicrobial peptides, and we observed that IFN-β can directly kill Staphylococcus aureus Further, a mutant S. aureus that is more sensitive to antimicrobial peptides was killed more efficiently by IFN-β than was the wild-type S...
May 15, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
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