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https://www.readbyqxmd.com/read/28733600/%C3%AE-ginkgotides-hyperdisulfide-constrained-peptides-from-ginkgo-biloba
#1
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
#2
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
#3
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-pna-via-post-synthetic-modification-with-hydrophilic-side-chains
#4
Chaturong Suparpprom, Thanesuan Nuanyai, Haruthai Pansuwan, Tirayut Vilaivan, Supason Wanichwecharungruang, Boonsong Ditmangklo, Tanapat Palaga, Porntip Pan-In, Banphot Jiangchareon, Chotima 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 limited in vivo applications of PNA. In previous strategies, the PNA can be conjugated to macromolecular carrier, or modified with positively charged side chains such as guanidinium groups to improve the aqueous solubility and/or cell permeability...
July 13, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28701689/lybatides-from-lycium-barbarum-contain-an-unusual-cystine-stapled-helical-peptide-scaffold
#5
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
#6
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
#7
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
#8
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/non-resonant-and-local-field-effects-in-peptidic-nanostructures-bearing-oligo-p-phenylenevinylene-units
#9
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 6, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28680440/vaccatides-antifungal-glutamine-rich-hevein-like-peptides-from-vaccaria-hispanica
#10
Ka H Wong, Wei Liang Tan, Shruthi G Kini, Tianshu Xiao, Aida Serra, Sui Kwan Sze, James P Tam
Hevein and hevein-like peptides are disulfide-constrained chitin-binding cysteine-rich peptides. They are divided into three subfamilies, 6C-, 8C-, and 10C-hevein-like peptides, based on the number of cysteine residues. In addition, hevein-like peptides can exist in two forms, short and long. The long C-terminal form found in hevein and 10C-hevein-like peptides contain a C-terminal protein cargo. In contrast, the short form without a protein cargo is found in all three subfamilies. Here, we report the discovery and characterization of two novel glutamine-rich and protein cargo-free 8C-hevein-like peptides, vaccatides vH1 and vH2, from Vaccaria hispanica of the Caryophyllaceae family...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28650634/reversible-and-versatile-on-tether-modification-of-chiral-center-induced-helical-peptides
#11
Kuan Hu, Chengjie Sun, Zigang Li
Modification of the cross-linker of constrained peptides has recently received considerable attention. Here, we present a versatile approach to modifing the cross-linking tether of chiral-center-induced helical (CIH) peptides via the S-alkylation reaction. The alkylation process displayed high conversion efficiency, selectivity, and substrate tolerance. Notably, although on-tether S-alkylation could lead to a pair of peptide epimers, the major alkylated product retained the helical structure of its helical precursor peptide...
July 6, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28642715/elastin-like-protein-with-statherin-derived-peptide-controls-fluorapatite-formation-and-morphology
#12
Kseniya Shuturminska, Nadezda V Tarakina, Helena S Azevedo, Andrew J Bushby, Alvaro Mata, Paul Anderson, Maisoon Al-Jawad
The process of enamel biomineralization is multi-step, complex and mediated by organic molecules. The lack of cells in mature enamel leaves it unable to regenerate and hence novel ways of growing enamel-like structures are currently being investigated. Recently, elastin-like protein (ELP) with the analog N-terminal sequence of statherin (STNA15-ELP) has been used to regenerate mineralized tissue. Here, the STNA15-ELP has been mineralized in constrained and unconstrained conditions in a fluoridated solution...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28636317/downsizing-proto-oncogene-cfos-to-short-helix-constrained-peptides-that-bind-jun
#13
Daniel Baxter, Samuel R Perry, Timothy A Hill, W Mei Kok, Nathan R Zaccai, R Leo Brady, David P Fairlie, Jody M Mason
The oncogenic transcription factor activator protein-1 (AP-1) is a DNA-binding protein that assembles through dimerization of Fos and Jun protein subunits, their leucine-rich helical sequences entwining into a coiled-coil structure. This study reports on downsizing the proto-oncogene cFos protein (380 residues) to shorter peptides (37-25 residues) modified with helix-inducing constraints to enhance binding to Jun. A crystal structure is reported for a 37-residue Fos-derived peptide (FosW) bound to Jun. This guided iterative downsizing of FosW to shorter peptide sequences that were constrained into stable water-soluble α-helices by connecting amino acid side chains to form cyclic pentapeptide components...
June 21, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28630351/evolutionary-radiation-of-lanthipeptides-in-marine-cyanobacteria
#14
Andres Cubillos-Ruiz, Jessie W Berta-Thompson, Jamie W Becker, Wilfred A van der Donk, Sallie W Chisholm
Lanthipeptides are ribosomally derived peptide secondary metabolites that undergo extensive posttranslational modification. Prochlorosins are a group of lanthipeptides produced by certain strains of the ubiquitous marine picocyanobacteria Prochlorococcus and Synechococcus Unlike other lanthipeptide-producing bacteria, picocyanobacteria use an unprecedented mechanism of substrate promiscuity for the production of numerous and diverse lanthipeptides using a single lanthionine synthetase. Through a cross-scale analysis of prochlorosin biosynthesis genes-from genomes to oceanic populations-we show that marine picocyanobacteria have the collective capacity to encode thousands of different cyclic peptides, few of which would display similar ring topologies...
July 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28626832/fragment-binding-to-%C3%AE-secretase-1-without-catalytic-aspartate-interactions-identified-via-orthogonal-screening-approaches
#15
Frederik J R Rombouts, Richard Alexander, Erna Cleiren, Alex De Groot, Michel Carpentier, Joyce Dijkmans, Katleen Fierens, Stefan Masure, Diederik Moechars, Martina Palomino-Schätzlein, Antonio Pineda-Lucena, Andrés A Trabanco, Daan Van Glabbeek, Ann Vos, Gary Tresadern
An approach to identify β-secretase 1 (BACE1) fragment binders that do not interact with the catalytic aspartate dyad is presented. A ThermoFluor (thermal shift) and a fluorescence resonance energy transfer enzymatic screen on the soluble domain of BACE1, together with a surface plasmon resonance (SPR) screen on the soluble domain of BACE1 and a mutant of one catalytic Asp (D32N), were run in parallel. Fragments that were active in at least two of these assays were further confirmed using one-dimensional NMR (WaterLOGSY) and SPR binding competition studies with peptidic inhibitor OM99-2...
February 28, 2017: ACS Omega
https://www.readbyqxmd.com/read/28598597/azapeptide-synthesis-methods-for-expanding-side-chain-diversity-for-biomedical-applications
#16
Ramesh Chingle, Caroline Proulx, William D Lubell
Mimicry of bioactive conformations is critical for peptide-based medicinal chemistry because such peptidomimetics may augment stability, enhance affinity, and increase specificity. Azapeptides are peptidomimetics in which the α-carbon(s) of one or more amino acid residues are substituted by nitrogen. The resulting semicarbazide analogues have been shown to reinforce β-turn conformation through the combination of lone pair-lone pair repulsion of the adjacent hydrazine nitrogen and urea planarity. Substitution of a semicarbazide for an amino amide residue in a peptide may retain biological activity and add benefits such as improved metabolic stability...
June 9, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28580915/the-potential-use-of-single-particle-electron-microscopy-as-a-tool-for-structure-based-inhibitor-design
#17
S Rawson, M J McPhillie, R M Johnson, C W G Fishwick, S P Muench
Recent developments in electron microscopy (EM) have led to a step change in our ability to solve the structures of previously intractable systems, especially membrane proteins and large protein complexes. This has provided new opportunities in the field of structure-based drug design, with a number of high-profile publications resolving the binding sites of small molecules and peptide inhibitors. There are a number of advantages of EM over the more traditional X-ray crystallographic approach, such as resolving different conformational states and permitting the dynamics of a system to be better resolved when not constrained by a crystal lattice...
June 1, 2017: Acta Crystallographica. Section D, Structural Biology
https://www.readbyqxmd.com/read/28579436/intranasal-vaccination-with-an-adjuvanted-polyphosphazenes-nanoparticle-based-vaccine-formulation-stimulates-protective-immune-responses-in-mice
#18
Kai Schulze, Thomas Ebensen, Lorne A Babiuk, Volker Gerdts, Carlos A Guzman
The most promising strategy to sustainably prevent infectious diseases is vaccination. However, emerging as well as re-emerging diseases still constitute a considerable threat. Furthermore, lack of compliance and logistic constrains often result in the failure of vaccination campaigns. To overcome these hurdles, novel vaccination strategies need to be developed, which fulfill maximal safety requirements, show maximal efficiency and are easy to administer. Mucosal vaccines constitute promising non-invasive approaches able to match these demands...
June 1, 2017: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/28570824/protein-epitope-mimetics-from-new-antibiotics-to-supramolecular-synthetic-vaccines
#19
Katja Zerbe, Kerstin Moehle, John A Robinson
Protein epitope mimetics provide powerful tools to study biomolecular recognition in many areas of chemical biology. They may also provide access to new biologically active molecules and potentially to new classes of drug and vaccine candidates. Here we highlight approaches for the design of folded, structurally defined epitope mimetics, by incorporating backbone and side chains of hot residues onto a stable constrained scaffold. Using robust synthetic methods, the structural, biological, and physical properties of epitope mimetics can be optimized, by variation of both side chain and backbone chemistry...
June 1, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28561588/protein-domain-mimics-as-modulators-of-protein-protein-interactions
#20
Nicholas Sawyer, Andrew M Watkins, Paramjit S Arora
Protein-protein interactions (PPIs) are ubiquitous in biological systems and often misregulated in disease. As such, specific PPI modulators are desirable to unravel complex PPI pathways and expand the number of druggable targets available for therapeutic intervention. However, the large size and relative flatness of PPI interfaces make them challenging molecular targets. This Account describes our systematic approach using secondary and tertiary protein domain mimics (PDMs) to specifically modulate PPIs. Our strategy focuses on mimicry of regular secondary and tertiary structure elements from one of the PPI partners to inspire rational PDM design...
May 31, 2017: Accounts of Chemical Research
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