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Model amphipathic peptide

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https://www.readbyqxmd.com/read/28236791/lipid-selectivity-in-novel-antimicrobial-peptides-implication-on-antimicrobial-and-hemolytic-activity
#1
P Maturana, M Martinez, M E Noguera, N C Santos, E A Disalvo, L Semorile, P C Maffia, A Hollmann
Antimicrobial peptides (AMPs) are small cationic molecules that display antimicrobial activity against a wide range of bacteria, fungi and viruses. For an AMP to be considered as a therapeutic option, it must have not only potent antibacterial properties but also low hemolytic and cytotoxic activities [1]. Even though many studies have been conducted in order to correlate the antimicrobial activity with affinity toward model lipid membranes, the use of these membranes to explain cytotoxic effects (especially hemolysis) has been less explored...
February 13, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28196861/molecular-determinants-of-the-n-terminal-acetyltransferase-naa60-anchoring-to-the-golgi-membrane
#2
Henriette Aksnes, Marianne Goris, Øyvind Strømland, Adrian Drazic, Qaiser Waheed, Nathalie Reuter, Thomas Arnesen
Nα-acetyltransferase 60 (Naa60 or NatF) was recently identified as an unconventional N-terminal acetyltransferase (NAT) since it localizes to organelles, in particular the Golgi apparatus, and has a preference for acetylating N-termini of transmembrane proteins. This knowledge challenged the prevailing view of N-terminal acetylation as a co-translational ribosome-associated process and suggested a new mechanistic functioning for the enzymes responsible for this increasingly recognized protein modification...
February 14, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28193076/integration-of-quartz-crystal-microbalance-dissipation-and-reflection-mode-localized-surface-plasmon-resonance-sensors-for-biomacromolecular-interaction-analysis
#3
Abdul Rahim Ferhan, Joshua A Jackman, Nam-Joon Cho
The combination of label-free, surface-sensitive measurement techniques based on different physical principles enables detailed characterization of biomacromolecular interactions at solid-liquid interfaces. To date, most combined measurement systems have involved experimental techniques with similar probing volumes, whereas the potential of utilizing techniques with different surface sensitivities remains largely unexplored, especially for data interpretation. Herein, we report a combined measurement approach that integrates a conventional quartz crystal microbalance-dissipation (QCM-D) setup with a reflection-mode localized surface plasmon (LSPR) sensor...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28138522/the-activation-loop-of-pip5k-functions-as-a-membrane-sensor-essential-for-lipid-substrate-processing
#4
Aizhuo Liu, Dexin Sui, Dianqing Wu, Jian Hu
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K), a representative member of the phosphatidylinositol phosphate kinase (PIPK) family, is a major enzyme that biosynthesizes the signaling molecule PI(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) in eukaryotic cells. The stringent specificity toward lipid substrates and the high sensitivity to the membrane environment strongly suggest a membrane-sensing mechanism, but the underlying structural basis is still largely unknown. We present a nuclear magnetic resonance (NMR) study on a peptide commensurate with a PIP5K's activation loop, which has been reported to be a determinant of lipid substrate specificity and subcellular localization of PIP5K...
November 2016: Science Advances
https://www.readbyqxmd.com/read/28126403/binding-of-amphipathic-cell-penetrating-peptide-p28-to-wild-type-and-mutated-p53-as-studied-by-raman-atomic-force-and-surface-plasmon-resonance-spectroscopies
#5
Sara Signorelli, Simona Santini, Tohru Yamada, Anna Rita Bizzarri, Craig W Beattie, Salvatore Cannistraro
BACKGROUND: Mutations within the DNA binding domain (DBD) of the tumor suppressor p53 are found in >50% of human cancers and may significantly modify p53 secondary structure impairing its function. p28, an amphipathic cell-penetrating peptide, binds to the DBD through hydrophobic interaction and induces a posttranslational increase in wildtype and mutant p53 restoring functionality. We use mutation analyses to explore which elements of secondary structure may be critical to p28 binding...
April 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28073163/hydrocarbon-stapled-lipopeptides-exhibit-selective-antimicrobial-activity
#6
Zachary B Jenner, Christopher M Crittenden, Martín Gonzalez, Jennifer S Brodbelt, Kerry A Bruns
Antimicrobial peptides (AMPs) occur widely in nature and have been studied for their therapeutic potential. AMPs are of interest due to the large number of possible chemical structural combinations using natural and unnatural amino acids, with varying effects on their biological activities. Using physicochemical properties from known naturally occurring amphipathic cationic AMPs, several hydrocarbon-stapled lipopeptides (HSLPs) were designed, synthesized, and tested for antimicrobial properties. Peptides were chemically modified by N-terminal acylation, C-terminal amidation, and some were hydrocarbon stapled by intramolecular olefin metathesis...
January 10, 2017: Biopolymers
https://www.readbyqxmd.com/read/28068080/effect-of-the-southeast-asian-ovalocytosis-deletion-on-the-conformational-dynamics-of-signal-anchor-transmembrane-segment-1-of-red-cell-anion-exchanger-1-ae1-band-3-or-slc4a1
#7
Philip W Fowler, Mark S P Sansom, Reinhart A F Reithmeier
The first transmembrane (TM1) helix in the red cell anion exchanger (AE1, Band 3, or SLC4A1) acts as an internal signal anchor that binds the signal recognition particle and directs the nascent polypeptide chain to the endoplasmic reticulum (ER) membrane where it moves from the translocon laterally into the lipid bilayer. The sequence N-terminal to TM1 forms an amphipathic helix that lies at the membrane interface and is connected to TM1 by a bend at Pro403. Southeast Asian ovalocytosis (SAO) is a red cell abnormality caused by a nine-amino acid deletion (Ala400-Ala408) at the N-terminus of TM1...
February 7, 2017: Biochemistry
https://www.readbyqxmd.com/read/27951656/amphiphilicity-is-a-key-determinant-in-the-membrane-interactions-of-synthetic-14-mer-cationic-peptide-analogues
#8
Matthieu Fillion, Maxime Goudreault, Normand Voyer, Burkhard Bechinger, Michèle Auger
Cationic antimicrobial peptides are a component of the innate immune system of several organisms and represent an interesting alternative to fight multiresistant bacteria. In this context, we have elaborated a synthetic peptide scaffold allowing the study of the impact of different molecular determinants on the membrane interactions. The aim of the present study was to elucidate the mechanism of action of two cationic peptides that derive from a neutral 14-mer template peptide and where the hydrophilic portion is composed of a crown ether...
December 13, 2016: Biochemistry
https://www.readbyqxmd.com/read/27912176/novel-designed-vmct1-analogs-with-increased-antimicrobial-activity
#9
Cibele Nicolaski Pedron, Marcelo Der Torossian Torres, Julia Aparecida da Silva Lima, Pedro Ismael Silva, Fernanda Dias Silva, Vani Xavier Oliveira
Antimicrobial peptides are biologically active molecules produced by a wide range of organisms as an essential component of the innate immune response. They have recently attracted great interest, since they have antimicrobial activity against a broad spectrum of microorganisms. VmCT1 is a cationic peptide from the venom of Vaejovis mexicanus smithi scorpions, which presents antibacterial activity and tends to helical structures. Its analogs were synthesized, characterized and the conformational studies were performed by circular dichroism...
January 27, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/27761988/delivering-structural-information-on-the-polar-face-of-membrane-active-peptides-19-f-nmr-labels-with-a-cationic-side-chain
#10
Oleg M Michurin, Sergii Afonin, Marina Berditsch, Constantin G Daniliuc, Anne S Ulrich, Igor V Komarov, Dmytro S Radchenko
Conformationally constrained non-racemizing trifluoromethyl-substituted lysine isosteres [(E)- and (Z)-TCBLys] with charged side chains are presented as a new type of (19) F-NMR labels for peptide studies. Design of the labels, their synthesis, incorporation into peptides and experimental demonstration of their application for solid state NMR studies of membrane-active peptides are described. A series of fluorine-labeled analogues of the helical amphipathic antimicrobial peptide PGLa(Nle) was obtained, in which different lysine residues in the original peptide sequence were replaced, one at a time, by either (E)- or (Z)-TCBLys...
November 14, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27679488/inhibition-of-insulin-amyloid-fibrillation-by-a-novel-amphipathic-heptapeptide-mechanistic-details-studied-by-spectroscopy-in-combination-with-microscopy
#11
Bhisma N Ratha, Anirban Ghosh, Jeffrey R Brender, Nilanjan Gayen, Humaira Ilyas, Chilukoti Neeraja, Kali P Das, Atin K Mandal, Anirban Bhunia
The aggregation of insulin into amyloid fibers has been a limiting factor in the development of fast acting insulin analogues, creating a demand for excipients that limit aggregation. Despite the potential demand, inhibitors specifically targeting insulin have been few in number. Here we report a non-toxic and serum stable-designed heptapeptide, KR7 (KPWWPRR-NH2), that differs significantly from the primarily hydrophobic sequences that have been previously used to interfere with insulin amyloid fibrillation...
November 4, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27664499/stability-of-an-amphipathic-helix-hairpin-surfactant-peptide-in-liposomes
#12
Alan J Waring, Monik Gupta, Larry M Gordon, Gary Fujii, Frans J Walther
Surfactant protein B (SP-B; 79 residues) is a member of the saposin superfamily and plays a pivotal role in lung function. The N- and C-terminal regions of SP-B, cross-linked by two disulfides, were theoretically predicted to fold as charged amphipathic helices, suggesting participation in surfactant activities. Previous studies with oxidized Super Mini-B (SMB), a construct based on the N- and C-regions of SP-B (i.e., residues 1-25 and 63-78) joined with a designer turn (-PKGG-) and two disulfides, indicated that freshly prepared SMB in lipids folded as a surface active, α-helix-hairpin...
December 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27664329/optimization-of-in-vivo-dna-delivery-with-nickfect-peptide-vectors
#13
Krista Freimann, Piret Arukuusk, Kaido Kurrikoff, Luís Daniel Ferreira Vasconcelos, Kadi-Liis Veiman, Julia Uusna, Helerin Margus, Alfonso T Garcia-Sosa, Margus Pooga, Ülo Langel
As the field of gene therapy progresses, an increasingly urgent need has arisen for efficient and non-toxic vectors for the in vivo delivery of nucleic acids. Cell-penetrating peptides (CPP) are very efficient transfection reagents in vitro, however, their application in vivo needs improvement. To enhance in vivo transfection we designed various CPPs based on previous knowledge of internalization studies and physiochemical properties of NickFect (NF) nanoparticles. We show that increment of the helicity of these Transportan10 analogues improves the transfection efficiency...
November 10, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/27616720/panusin-represents-a-new-family-of-%C3%AE-defensin-like-peptides-in-invertebrates
#14
Vivian Montero-Alejo, Gerardo Corzo, Javier Porro-Suardíaz, Zenia Pardo-Ruiz, Erick Perera, Leandro Rodríguez-Viera, Gabriela Sánchez-Díaz, Erix Wiliam Hernández-Rodríguez, Carlos Álvarez, Steve Peigneur, Jan Tytgat, Rolando Perdomo-Morales
Beta_defensin have been solely found in vertebrates until β-defensin-like peptides were described as transcript isoforms in two species of Panulirus genus. They were considered as putative antimicrobials since their biological activity have not been demonstrated. Here we purified and characterized a defensin-like peptide from the hemocytes of spiny lobster P. argus, hereafter named panusin. Structurally, panusin presents a cysteine-stabilized α/β motif, and is prone to form homodimers. Biological activity of panusin showed broad-spectrum antimicrobial activity, characterized for being strikingly salt-resistant...
February 2017: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/27586181/apolipoprotein-mimetic-peptides-as-modulators-of-lipoprotein-function
#15
G M Anantharamaiah, David W Garber, C Roger White
Apolipoprotein (apo)A-I and apoE are the two protein components that have been extensively investigated for their anti-atherogenic properties. Both apolipoproteins possess amphipathic helical structures, responsible for the solubilization of lipids. While apoA-I possesses class A amphipathic helical structures, apoE possesses a 59 residue long amphipathic helical domain linked to a four helix bundle containing the Arg-rich, 10 residue receptor binding domain. An 18 residue model peptide (18A) was designed to mimic the amphipathic helical domains of apoA-I...
2016: Protein and Peptide Letters
https://www.readbyqxmd.com/read/27532129/a-model-for-dimerization-of-the-sox-group-e-transcription-factor-family
#16
Sarah N Ramsook, Joyce Ni, Shokofeh Shahangian, Ana Vakiloroayaei, Naveen Khan, Jamie J Kwan, Logan W Donaldson
Group E members of the SOX transcription factor family include SOX8, SOX9, and SOX10. Preceding the high mobility group (HMG) domain in each of these proteins is a thirty-eight amino acid region that supports the formation of dimers on promoters containing tandemly inverted sites. The purpose of this study was to obtain new structural insights into how the dimerization region functions with the HMG domain. From a mutagenic scan of the dimerization region, the most essential amino acids of the dimerization region were clustered on the hydrophobic face of a single, predicted amphipathic helix...
2016: PloS One
https://www.readbyqxmd.com/read/27529120/antimicrobial-peptide-simulations-and-the-influence-of-force-field-on-the-free-energy-for-pore-formation-in-lipid-bilayers
#17
W F Drew Bennett, Chun Kit Hong, Yi Wang, D Peter Tieleman
Due to antimicrobial resistance, the development of new drugs to combat bacterial and fungal infections is an important area of research. Nature uses short, charged, and amphipathic peptides for antimicrobial defense, many of which disrupt the lipid membrane in addition to other possible targets inside the cell. Computer simulations have revealed atomistic details for the interactions of antimicrobial peptides and cell-penetrating peptides with lipid bilayers. Strong interactions between the polar interface and the charged peptides can induce bilayer deformations - including membrane rupture and peptide stabilization of a hydrophilic pore...
September 13, 2016: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/27465683/alternate-promoter-usage-generates-two-subpopulations-of-the-neuronal-rhogef-kalirin-7
#18
Megan B Miller, Yan Yan, Yi Wu, Bing Hao, Richard E Mains, Betty A Eipper
Kalirin (Kal), a dual Rho GDP/GTP exchange factor (GEF), plays essential roles within and outside the nervous system. Tissue-specific, developmentally regulated alternative splicing generates isoforms with one (Kal7) or two (Kal9, Kal12) GEF domains along with a kinase (Kal12) domain; while Kal9 and Kal12 are crucial for neurite outgrowth, Kal7 plays important roles in spine maintenance and synaptic plasticity. Tissue-specific usage of alternate Kalrn promoters (A, B, C, D) places four different peptides before the Sec14 domain...
July 28, 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27450123/conformational-study-of-melectin-and-antapin-antimicrobial-peptides-in-model-membrane-environments
#19
Lucie Kocourková, Pavlína Novotná, Sabína Čujová, Václav Čeřovský, Marie Urbanová, Vladimír Setnička
Antimicrobial peptides have long been considered as promising compounds against drug-resistant pathogens. In this work, we studied the secondary structure of antimicrobial peptides melectin and antapin using electronic (ECD) and vibrational circular dichroism (VCD) spectroscopies that are sensitive to peptide secondary structures. The results from quantitative ECD spectral evaluation by Dichroweb and CDNN program and from the qualitative evaluation of the VCD spectra were compared. The antimicrobial activity of the selected peptides depends on their ability to adopt an amphipathic α-helical conformation on the surface of the bacterial membrane...
January 5, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/27442521/nonhemolytic-cell-penetrating-peptides-site-specific-introduction-of-glutamine-and-lysine-residues-into-the-%C3%AE-helical-peptide-causes-deletion-of-its-direct-membrane-disrupting-ability-but-retention-of-its-cell-penetrating-ability
#20
Seoyeon Kim, Soonsil Hyun, Yuri Lee, Yan Lee, Jaehoon Yu
Cell-penetrating peptides (CPPs) often have cationic and amphipathic characteristics that are commonly associated with α-helical peptides. These features give CPPs both membrane demolishing and penetrating abilities. To make CPPs safe for biomedical applications, their toxicities resulting from their membrane demolishing abilities must be removed while their cell penetrating abilities must be retained. In this study, we systematically constructed mutants of the amphipathic α-helical model peptide (LKKLLKLLKKLLKLAG, LK peptide)...
September 12, 2016: Biomacromolecules
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