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https://www.readbyqxmd.com/read/28917447/cell-penetrating-peptides-to-dissect-host-pathogen-protein-protein-interactions-in-theileria-transformed-leukocytes
#1
REVIEW
Malak Haidar, Perle Latré de Laté, Eileen J Kennedy, Gordon Langsley
One powerful application of cell penetrating peptides is the delivery into cells of molecules that function as specific competitors or inhibitors of protein-protein interactions. Ablating defined protein-protein interactions is a refined way to explore their contribution to a particular cellular phenotype in a given disease context. Cell-penetrating peptides can be synthetically constrained through various chemical modifications that stabilize a given structural fold with the potential to improve competitive binding to specific targets...
September 7, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28911855/conformationally-constrained-peptides-target-the-allosteric-kinase-dimer-interface-and-inhibit-egfr-activation
#2
Melody D Fulton, Laura E Hanold, Zheng Ruan, Sneha Patel, Aaron M Beedle, Natarajan Kannan, Eileen J Kennedy
Although EGFR is a highly sought-after drug target, inhibitor resistance remains a challenge. As an alternative strategy for kinase inhibition, we sought to explore whether allosteric activation mechanisms could effectively be disrupted. The kinase domain of EGFR forms an atypical asymmetric dimer via head-to-tail interactions and serves as a requisite for kinase activation. The kinase dimer interface is primarily formed by the H-helix derived from one kinase monomer and the small lobe of the second monomer...
September 5, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28885004/gold-catalyzed-solid-phase-synthesis-of-3-4-dihydropyrazin-2-1h-ones-relevant-pharmacophores-and-peptide-backbone-constraints
#3
Adam Přibylka, Viktor Krchňák
Here, we report the efficient solid-phase synthesis of N-propargyl peptides using Fmoc-amino acids and propargyl alcohol as key building blocks. Gold-catalyzed nucleophilic addition to the triple bond induced C-N bond formation, which triggered intramolecular cyclization, yielding 1,3,4-trisubstituted-5-methyl-3,4-dihydropyrazin-2(1H)-ones. Conformations of acyclic and constrained peptides were compared using a two-step conformer distribution analysis at the molecular mechanics level and density functional theory...
September 12, 2017: ACS Combinatorial Science
https://www.readbyqxmd.com/read/28882503/synthesis-and-%C3%AE-sheet-propensity-of-constrained-n-amino-peptides
#4
Matthew P Sarnowski, Kyle P Pedretty, Nicole Giddings, H Lee Woodcock, Juan R Del Valle
The stabilization of β-sheet secondary structure through peptide backbone modification represents an attractive approach to protein mimicry. Here, we present strategies toward stable β-hairpin folds based on peptide strand N-amination. Novel pyrazolidinone and tetrahydropyridazinone dipeptide constraints were introduced via on-resin Mitsunobu cyclization between α-hydrazino acid residues and a serine or homoserine side chain. Acyclic and cyclic N-amino peptide building blocks were then evaluated for their effect on β-hairpin stability in water using a GB1-derived model system...
August 31, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28844788/spatiotemporal-resolution-of-spinal-meningeal-and-parenchymal-inflammation-during-experimental-autoimmune-encephalomyelitis
#5
Bandana Shrestha, Xi Jiang, Shujun Ge, Debayon Paul, Peter Chianchiano, Joel S Pachter
Experimental autoimmune encephalomyelitis (EAE) induced by active immunization of C57BL/6 mice with peptide from myelin oligodendrocyte protein (MOG35-55), is a neuroinflammatory, demyelinating disease widely recognized as an animal model of multiple sclerosis (MS). Typically, EAE presents with an ascending course of paralysis, and inflammation that is predominantly localized to the spinal cord. Recent studies have further indicated that inflammation - in both MS and EAE - might initiate within the meninges and propagate from there to the underlying parenchyma...
August 24, 2017: Neurobiology of Disease
https://www.readbyqxmd.com/read/28833777/peptide-macrocycles-developed-from-precisely-regulated-cyclization-of-unprotected-peptides
#6
Jinghui Wang, Mirao Zha, Qianran Fei, Weidong Liu, Yibing Zhao, Chuanliu Wu
Peptide macrocycles have been attractive scaffolds for the development of ligands and inhibitors to proteins, which have the potential of being developed as potent drugs. Novel strategies for peptide macrocyclization should be of particular interest to peptide drug design and discovery. Here, we report an efficient strategy for designing and synthesizing macrocyclic peptides, which relies on the precisely-regulated and efficient one-pot cyclization of unprotected peptides with 2,3,5,6-tetrafluoroterephthalonitrile (4F-2CN)...
August 22, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28811070/evaluation-of-sequence-variability-in-hiv-1-gp41-c-peptide-helix-grafted-proteins
#7
Rachel L Tennyson, Susanne N Walker, Terumasa Ikeda, Reuben S Harris, Brian R McNaughton
Many therapeutically-relevant protein-protein interactions (PPIs) have been reported that feature a helix and helix-binding cleft at the interface. Given this, different approaches to disrupting such PPIs have been developed. While short peptides (<15 amino acids) typically do not fold into a stable helix, researchers have reported chemical approaches to constraining helix structure. However, these approaches rely on laborious, and often expensive, chemical synthesis and purification. Our premise is that protein-based solutions that stabilize a therapeutically-relevant helix offer a number of advantages...
August 1, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28805888/development-of-small-intestinal-enzyme-activities-and-their-relationship-with-some-gut-regulatory-peptides-in-grazing-sheep
#8
C L Wang, X Lang, P J Wu, D P Casper, F D Li
Growth depends on an animal's capacity to digest and assimilate ingested nutrients, and insufficient supply and impairment will constrain lamb growth. Eight groups of Alpine Finewool lambs were harvested on 0, 3, 7, 14, 21, 28, 42, and 56 d to measure pH and enzymatic activities in the duodenum, proximal jejunum, middle jejunum, distal jejunum, and ileum mucosa or digesta. From the duodenum to the ileum the pH of intestinal mucosa and digesta increased, whereas pH changed very little with age. The trypsin, chymotrypsin, lipase, lactase, and α-amylase activities observed at birth decreased by d 3, followed by a nonuniform enzymatic response in the small intestine...
August 2017: Journal of Animal Science
https://www.readbyqxmd.com/read/28782780/synthesis-and-conformational-analysis-of-peptides-embodying-2-3-methanopipecolic-acids
#9
Luciano Ricci, Lorenzo Sernissi, Dina Scarpi, Francesca Bianchini, Alessandro Contini, Ernesto G Occhiato
The conformational analysis of linear and cyclic peptides incorporating 2,3-methanopipecolic acids (or Cyclopropane Pipecolic Acids, CPAs) as conformationally constrained α-amino acids is reported. Compared to peptides containing proline or pipecolic acid, a striking increase of the cis isomer (42-92%) around the CPA amide bond is observed, both in water and organic solvents, when these unnatural amino acids are embodied in linear amino acid sequences. The rotational barrier around the same bond in water was calculated, giving results comparable to that for the prolyl cis/trans isomerization...
August 16, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28777495/increased-conformational-flexibility-of-a-macrocycle-receptor-complex-contributes-to-reduced-dissociation-rates
#10
Adrian Glas, Eike-Christian Wamhoff, Dennis M Krüger, Christoph Rademacher, Tom N Grossmann
Constraining a peptide in its bioactive conformation via macrocyclization represents a powerful strategy to design modulators of challenging biomolecular targets. This holds particularly true for the development of inhibitors of protein-protein interactions which often involve interfaces lacking defined binding pockets. Such flat surfaces are demanding targets for traditional small molecules rendering macrocyclic peptides promising scaffolds for novel therapeutics. However, the contribution of peptide dynamics to binding kinetics is barely understood which impedes the design process...
August 4, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28758361/igy-binding-peptide-screened-from-a-random-peptide-library-as-a-ligand-for-igy-purification
#11
Kamrul Hasan Khan, Arisa Himeno, Shouhei Kosugi, Yosuke Nakashima, Abdur Rafique, Ayana Imamura, Takaaki Hatanaka, Dai-Ichiro Kato, Yuji Ito
Chicken egg yolk immunoglobulin (IgY) is a functional substitute for mammalian IgG for antigen detection. Traditional IgY purification methods involve multi-step procedures resulting in low purity and recovery of IgY. In this study, we developed a simple IgY purification system using IgY-specific peptides identified by T7 phage display technology. From disulfide-constrained random peptide libraries constructed on a T7 phage, we identified three specific binding clones (Y4-4, Y5-14, and Y5-55) through repeated biopanning...
July 31, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/28733600/%C3%AE-ginkgotides-hyperdisulfide-constrained-peptides-from-ginkgo-biloba
#12
Ka H Wong, Wei Liang Tan, Tianshu Xiao, James P Tam
Hyperdisulfide-constrained peptides are distinguished by their high stability and diverse functions. Thus far, these peptides have been reported from animals only but their occurrence in plants are rare. Here, we report the discovery, synthesis and characterization of a hyperdisulfide-constrained peptides family of approximately 2 kDa, β-ginkgotides (β-gB1 and β-gB2) from Ginkgo biloba. Proteomic analysis showed β-ginkgotides contain 18‒20 amino acids, of which 16 residues form a conserved six-cysteine core with a highly clustered cysteine spacing of C‒CC‒C‒CC, an arrangement that has not been reported in cysteine-rich peptides...
July 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28719188/phage-selection-of-cyclic-peptides-for-application-in-research-and-drug-development
#13
Kaycie Deyle, Xu-Dong Kong, Christian Heinis
Cyclic peptides can bind to protein targets with high affinities and selectivities, which makes them an attractive modality for the development of research reagents and therapeutics. Additional properties, including low inherent toxicity, efficient chemical synthesis, and facile modification with labels or immobilization reagents, increase their attractiveness. Cyclic peptide ligands against a wide range of protein targets have been isolated from natural sources such as bacteria, fungi, plants, and animals...
July 18, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28715199/jumping-hurdles-peptides-able-to-overcome-biological-barriers
#14
Macarena Sánchez-Navarro, Meritxell Teixidó, Ernest Giralt
The cell membrane, the gastrointestinal tract, and the blood-brain barrier (BBB) are good examples of biological barriers that define and protect cells and organs. They impose different levels of restriction, but they also share common features. For instance, they all display a high lipophilic character. For this reason, hydrophilic compounds, like peptides, proteins, or nucleic acids have long been considered as unable to bypass them. However, the discovery of cell-penetrating peptides (CPPs) opened a vast field of research...
July 17, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28704609/hydrophilic-and-cell-penetrable-pyrrolidinyl-peptide-nucleic-acid-via-post-synthetic-modification-with-hydrophilic-side-chains
#15
Haruthai Pansuwan, Boonsong Ditmangklo, Chotima Vilaivan, Banphot Jiangchareon, Porntip Pan-In, Supason Wanichwecharungruang, Tanapat Palaga, Thanesuan Nuanyai, Chaturong Suparpprom, Tirayut Vilaivan
Peptide nucleic acid (PNA) is a nucleic acid mimic in which the deoxyribose-phosphate was replaced by a peptide-like backbone. The absence of negative charge in the PNA backbone leads to several unique behaviors including a stronger binding and salt independency of the PNA-DNA duplex stability. However, PNA possesses poor aqueous solubility and cannot directly penetrate cell membranes. These are major obstacles that limit in vivo applications of PNA. In previous strategies, the PNA can be conjugated to macromolecular carriers or modified with positively charged side chains such as guanidinium groups to improve the aqueous solubility and cell permeability...
August 11, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28701689/lybatides-from-lycium-barbarum-contain-an-unusual-cystine-stapled-helical-peptide-scaffold
#16
Wei Liang Tan, Ka H Wong, Jian Lei, Naoki Sakai, Hong Wei Tan, Rolf Hilgenfeld, James P Tam
Cysteine-rich peptides (CRPs) of 2-6 kDa are generally thermally and proteolytically stable because of their multiple cross-bracing disulfide bonds. Here, we report the discovery and characterization of two novel cystine-stapled CRPs, designated lybatide 1 and 2 (lyba1 and lyba2), from the cortex of Lycium barbarum root. Lybatides, 32 to 33 amino acids in length, are hyperstable and display a novel disulfide connectivity with a cysteine motif of C-C-C-C-CC-CC which contains two pairs of adjacent cysteines (-CC-CC)...
July 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28690684/4-fluoroprolines-conformational-analysis-and-effects-on-the-stability-and-folding-of-peptides-and-proteins
#17
Robert W Newberry, Ronald T Raines
Proline is unique among proteinogenic amino acids because a pyrrolidine ring links its amino group to its side chain. This heterocycle constrains the conformations of the main chain and thus templates particular secondary structures. Proline residues undergo post-translational modification at the 4-position to yield 4-hydroxyproline, which is especially prevalent in collagen. Interest in characterizing the effects of this modification led to the use of 4-fluoroprolines to enhance inductive properties relative to the hydroxyl group of 4-hydroxyproline and to eliminate contributions from hydrogen bonding...
2017: Topics in Heterocyclic Chemistry
https://www.readbyqxmd.com/read/28688285/a-strategy-for-actualization-of-active-targeting-nanomedicine-practically-functioning-in-a-living-body
#18
Kyoung Jin Lee, Seol Hwa Shin, Jae Hee Lee, Eun Jin Ju, Yun-Yong Park, Jung Jin Hwang, Young-Ah Suh, Seung-Mo Hong, Se Jin Jang, Jung Shin Lee, Si Yeol Song, Seong-Yun Jeong, Eun Kyung Choi
Designing nanocarriers with active targeting has been increasingly emphasized as for an ideal delivery mechanism of anti-cancer therapeutic agents, but the actualization has been constrained by lack of reliable strategy ultimately applicable. Here, we designed and verified a strategy to achieve active targeting nanomedicine that works in a living body, utilizing animal models bearing a patient's tumor tissue and subjected to the same treatments that would be used in the clinic. The concept for this strategy was that a novel peptide probe and its counterpart protein, which responded to a therapy, were identified, and then the inherent ability of the peptide to target the designated tumor protein was used for active targeting in vivo...
June 30, 2017: Biomaterials
https://www.readbyqxmd.com/read/28683555/x-ray-crystallographic-structure-of-a-compact-dodecamer-from-a-peptide-derived-from-a%C3%AE-16-36
#19
Patrick J Salveson, Ryan K Spencer, Adam G Kreutzer, James S Nowick
The assembly of the β-amyloid peptide, Aβ, into soluble oligomers is associated with neurodegeneration in Alzheimer's disease. The Aβ oligomers are thought to be composed of β-hairpins. Here, the effect of shifting the residue pairing of the β-hairpins on the structures of the oligomers that form is explored through X-ray crystallography. Three residue pairings were investigated using constrained macrocyclic β-hairpins in which Aβ30-36 is juxtaposed with Aβ17-23, Aβ16-22, and Aβ15-21. The Aβ16-22-Aβ30-36 pairing forms a compact ball-shaped dodecamer composed of fused triangular trimers...
July 7, 2017: Organic Letters
https://www.readbyqxmd.com/read/28683194/nonresonant-and-local-field-effects-in-peptidic-nanostructures-bearing-oligo-p-phenylenevinylene-units
#20
Herdeline Ann M Ardoña, Tejaswini S Kale, Alyssa Ertel, John D Tovar
Peptide nanostructures with built-in electronic functions offer a new platform for biomaterial science. In this report, we interrogate the influences of the immediate peptide environment around oligo(p-phenylenevinylene) (OPV3) electronic units embedded within one-dimensional peptide nanostructures on the resulting photophysics as assessed by UV-vis, photoluminescence (PL), and circular dichroism spectroscopies. To do so, we studied peptide-core-peptide molecules where the core was either OPV3 or an aliphatic n-decyl chain...
July 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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