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Model amphipathic peptide

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...
October 20, 2016: Angewandte Chemie
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 targeted specifically at insulin have been few in number. Here we report a designed, non-toxic and serum stable heptapeptide, KR7 (KPWWPRR) that differs significantly from the primarily hydrophobic sequences that have been previously used to interfere with the insulin amyloid fibrillation...
September 27, 2016: Journal of Biological Chemistry
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...
September 21, 2016: Biochimica et Biophysica Acta
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
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...
September 8, 2016: Developmental and Comparative Immunology
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 the apolipoproteins possess amphipathic helical structure, responsible for the solubilization of lipids. While apoA-I possesses class A amphipathic helical structure, 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...
September 1, 2016: Protein and Peptide Letters
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
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
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
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
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
Saumya Bajaj, Debajit Dey, Rohan Bhukar, Mohit Kumar, Manidipa Banerjee
In the absence of lipid envelopes and associated fusion proteins, non-enveloped viruses employ membrane lytic peptides to breach the limiting membranes of host cells. Although several of these lytic peptides have been identified and characterized, their manner of deployment and interaction with host membranes remains unclear in most cases. We are using the gamma peptide of Flock House Virus (FHV), a model non-enveloped virus, to understand the mechanistic details of non-enveloped virus interaction with host cell membranes...
August 28, 2016: Journal of Molecular Biology
Alexander V Bocharov, Tinghuai Wu, Irina N Baranova, Anna A Birukova, Denis Sviridov, Tatyana G Vishnyakova, Alan T Remaley, Thomas L Eggerman, Amy P Patterson, Konstantin G Birukov
Synthetic amphipathic helical peptides (SAHPs) designed as apolipoprotein A-I mimetics are known to bind to class B scavenger receptors (SR-Bs), SR-BI, SR-BII, and CD36, receptors that mediate lipid transport and facilitate pathogen recognition. In this study, we evaluated SAHPs, selected for targeting human CD36, by their ability to attenuate LPS-induced inflammation, endothelial barrier dysfunction, and acute lung injury (ALI). L37pA, which targets CD36 and SR-BI equally, inhibited LPS-induced IL-8 secretion and barrier dysfunction in cultured endothelial cells while reducing lung neutrophil infiltration by 40% in a mouse model of LPS-induced ALI...
July 15, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Tomo Murayama, Sílvia Pujals, Hisaaki Hirose, Ikuhiko Nakase, Shiroh Futaki
The N-terminal amphipathic helical segment of adenovirus internal protein VI (AdVpVI) plays a critical role in viral infection. Here, we report that the peptide segment corresponding to AdVpVI (positions 33-55) can induce positive membrane curvature together with membrane perturbation. The enhanced perturbation ability of the peptide was observed for membranes containing negatively charged phospholipids. Based on the liposome leakage assay, substitution of leucine at position 40 to other aliphatic (isoleucine) and aromatic (phenylalanine and tryptophan) residues yielded a similar degree of membrane perturbation by the peptides, which was considerably diminished by the substitution to glutamine...
November 4, 2016: Biopolymers
Yongkang He, Xiaofeng He
Antimicrobial peptides (AMPs) have been the focus of intense research towards the finding of a viable alternative to current small-molecule antibiotics, owing to their commonly observed and naturally occurring resistance against pathogens. However, natural peptides have many problems such as low bioavailability and high allergenicity that largely limit the clinical applications of AMPs. In the present study, an integrative protocol that combined chemoinformatics modeling, molecular dynamics simulations, and in vitro susceptibility test was described to design AMPs containing unnatural amino acids (AMP-UAAs)...
September 2016: Biopolymers
Janely Pae, Laura Liivamägi, Dmitri Lubenets, Piret Arukuusk, Ülo Langel, Margus Pooga
Cell-penetrating peptides (CPPs) are considered as one of the most promising tools to mediate the cellular delivery of various biologically active compounds that are otherwise cell impermeable. CPPs can internalize into cells via two different pathways - endocytosis and direct translocation across the plasma membrane. In both cases, the initial step of internalization requires interactions between CPPs and different plasma membrane components. Despite the extensive research, it is not yet fully understood, which of these cell surface molecules mediate the direct translocation of CPPs across the plasma- and endosomal membrane...
August 2016: Biochimica et Biophysica Acta
Golnaz Mardani, Azam Bolhassani, Elnaz Agi, Sepideh Shahbazi, Seyed Mehdi Sadat
Two human papillomavirus (HPV) viral oncoproteins, E6 and E7 represent ideal targets for development of a therapeutic HPV vaccine. It is important to reduce the rate of HPV-associated malignancies through improvement of vaccine modalities. In this study, we used a short amphipathic peptide carrier, Pep-1, for delivery of the full-length HPV16 E7 protein into mammalian cells and evaluated immune responses and protective effects of different formulations in C57BL/6 tumor mice model. Our results showed that the complexes of E7/Pep-1 protein form stable nanoparticles through noncovalent binding with an average size of 120 to 250 nm...
June 2016: IUBMB Life
Xianglan Yao, Elizabeth M Gordon, Debbie M Figueroa, Amisha V Barochia, Stewart J Levine
Emerging roles are being recognized increasingly for apolipoproteins in the pathogenesis and treatment of lung diseases on the basis of their ability to suppress inflammation, oxidative stress, and tissue remodeling, and to promote adaptive immunity and host defense. Apolipoproteins, such as apolipoprotein E (apoE) and apolipoprotein A-I (apoA-I), are important components of lipoprotein particles that facilitate the transport of cholesterol, triglycerides, and phospholipids between plasma and cells. ApoE-containing lipoprotein particles are internalized into cells by low-density lipoprotein receptors (LDLRs), whereas apoA-I can interact with the ATP-binding cassette subfamily A member 1 (ABCA1) transporter to efflux cholesterol and phospholipids out of cells...
August 2016: American Journal of Respiratory Cell and Molecular Biology
Meng Xiong, Ming Chen, Jue Zhang
Antimicrobial peptides have long been raised as a promising strategy to combat bacterial infection in burn wounds. Here, we attempted to rationally design small antimicrobial peptides containing unnatural amino acids by integrating in silico analysis and in vitro assay. Predictive quantitative sequence-activity models were established and validated rigorously based on a large panel of nonamer antimicrobial peptides with known antibacterial activity. The best quantitative sequence-activity model predictor was employed to guide genetic evolution of a peptide population...
September 2016: Chemical Biology & Drug Design
Ashley S Massey, Sreekanth Pentlavalli, Richard Cunningham, Cian M McCrudden, Emma M McErlean, Philip Redpath, Ahlam A Ali, Stephanie Annett, John W McBride, Joanne McCaffrey, Tracy Robson, Marie E Migaud, Helen O McCarthy
Bisphosphonates (BPs) are a class of bone resorptive drug with a high affinity for the hydroxyapatite structure of bone matrices that are used for the treatment of osteoporosis. However, clinical application is limited by a common toxicity, BP-related osteonecrosis of the jaw. There is emerging evidence that BPs possess anticancer potential, but exploitation of these antiproliferative properties is limited by their toxicities. We previously reported the utility of a cationic amphipathic fusogenic peptide, RALA, to traffic anionic nucleic acids into various cell types in the form of cationic nanoparticles...
April 4, 2016: Molecular Pharmaceutics
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