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cyclization peptides

Chris Pepper, Henry Tu, Paul Morrill, Sara Garcia-Rates, Chris Fegan, Susan Greenfield
A 14mer peptide (T14) derived from the C-terminus of acetylcholinesterase (AChE) selectively activates metastatic breast cancer cells via the alpha-7 nicotinic receptor (α7 nAChR). This naturally occurring peptide is also present in brain, is elevated in Alzheimer's disease, and is antagonised by a cyclized variant (NBP-14). Here we investigated the effects of NBP-14 in six different cancer cell lines, primary leukemia B-cells and normal B-cells. All cells tested expressed α7 nAChR, intracellular and extracellular T14...
January 6, 2017: Oncotarget
Loida O Casalme, Arisa Yamauchi, Akinori Sato, Julie G Petitbois, Yasuyuki Nogata, Erina Yoshimura, Tatsufumi Okino, Taiki Umezawa, Fuyuhiko Matsuda
The total synthesis of dolastatin 16, a macrocyclic depsipeptide first isolated from the sea hare Dolabella auricularia as a potential antineoplastic metabolite by Pettit et al., was achieved in a convergent manner. Dolastatin 16 was reported by Tan to exhibit strong antifouling activity, and thus shows promise for inhibiting the attachment of marine benthic organisms such as Amphibalanus amphitrite to ships and submerged artificial structures. Therefore, dolastatin 16 is a potential compound for a new, environmentally friendly antifouling material to replace banned tributyltin-based antifouling paints...
January 11, 2017: Organic & Biomolecular Chemistry
Yuichi Amano, Naoki Umezawa, Shin Sato, Hisami Watanabe, Takashi Umehara, Tsunehiko Higuchi
We have previously employed cyclization of a linear peptide as a strategy to modulate peptide function and properties, but cleavage to regenerate the linear peptide left parts of the linker structure on the peptide, interfering with its activity. Here, we focused on cyclization of a linear peptide via a "traceless" disulfide-based linkage that would be cleaved and completely removed in a reducing environment, regenerating the original linear peptide without any linker-related structure. Thus, the linker would serve as a redox switch that would be activated in the intracellular environment...
December 23, 2016: Bioorganic & Medicinal Chemistry
Maria Mangini, Enrico Iaccino, Maria Giovanna Mosca, Selena Mimmi, Rosa D'Angelo, Ileana Quinto, Giuseppe Scala, Stefania Mariggiò
Expression of the lysophosphatidylinositol receptor GPR55 correlates with invasive potential of metastatic cells and bone metastasis formation of different types of tumors. These findings suggest a role for GPR55 signaling in cancer progression, including in lymphoproliferative diseases. Here, we screened a M13-phage-displayed random library using the bait of HEK293 cells that heterologously expressed full-length HA-GPR55. We selected a set of phagotopes that carried 7-mer insert peptides flanked by a pair of cysteine residues, which resulted in cyclized peptides...
December 23, 2016: Oncotarget
Biao Zhong, Chi Zhang, Shang Guo, Changqing Zhang
The human TGF-β/SMAD7 signaling has been recognized as an attractive target of heterotopic ossification (HO). Here, we report a successful rational design of cyclic peptides to disrupt the signaling pathway by targeting TGF-β-receptor complex. The intermolecular interaction between TGF-β and its cognate receptor is characterized in detail using molecular dynamics simulation, binding energetic analysis, and alanine scanning. With the computational analysis a binding loop of receptor protein is identified that plays an essential role in the peptide-mediated TGF-β-receptor interaction...
December 7, 2016: Journal of Molecular Graphics & Modelling
Rob M J Liskamp, Valerijs Korotkovs, Joachim Bijl, Claire Wilson, Helmus van de Langemheen, Sangram Kale, Christian Heinis
Two polar hinges have been developed for cyclization of peptides leading to bicyclic peptides and cyclized peptides with improved solubility and biological activity. Increasingly, we note that a good aqueous solubility of peptides is an absolute prerequisite not only to be able to handle and purify our target peptides but also crucial for biological activity characteristics. Compared to earlier hinges, the structurally similar but chemically very different TATB and TBMT each containing three nitrogen atoms were accessible in one step from bromo-acetonitrile...
December 16, 2016: Chembiochem: a European Journal of Chemical Biology
Suzanne M Batiste, Jeffrey N Johnston
Macrocyclic small molecules are attractive tools in the development of sensors, new materials, and therapeutics. Within early-stage drug discovery, they are increasingly sought for their potential to interact with broad surfaces of peptidic receptors rather than within their narrow folds and pockets. Cyclization of linear small molecule precursors is a straightforward strategy to constrain conformationally mobile motifs, but forging a macrocycle bond typically becomes more difficult at larger ring sizes. We report the development of a general approach to discrete collections of oligomeric macrocyclic depsipeptides using an oligomerization/macrocyclization process governed by a series of Mitsunobu reactions of hydroxy acid monomers...
December 27, 2016: Proceedings of the National Academy of Sciences of the United States of America
Diane N Le, Jan Riedel, Natalia Kozlyuk, Rachel W Martin, Vy M Dong
Dehydrophenylalanine is used as a traceless turn-inducer in the total synthesis of dichotomin E. Macrocyclization of the monomer is achieved in high yields and selectivity over cyclodimerization under conditions 100 times more concentrated than previously achieved. The enamide facilitates ring closing, and Rh-catalyzed hydrogenation of the unsaturated cyclic peptide results in selective formation of the natural product or its epimer, depending on our choice of phosphine ligand. NMR analysis and molecular modeling revealed that the linear peptide adopts a left-handed α-turn that preorganizes the N- and C-termini toward macrocyclization...
December 14, 2016: Organic Letters
Vania Teixeira, Marcelo Fernández, Natalia Oddone, Xiuli Zhang, Fabio Gallazzi, Hugo Cerecetto, Juan Pablo Gambini, Williams Porcal, Pablo Cabral, Thomas P Quinn
BACKGROUND: Lactam cyclized alpha-melanocyte stimulating hormone (α-MSH) analogues exhibit high stability and affinity for the MC1-R receptors over expressed in melanoma cells. Recently, we reported a novel <sup>99m</sup>Tc-HYNIC-cycMSH<sub>4-13</sub> analogue with the HYNIC chelator directly attached to the lactam cyclized ring. OBJECTIVE: In this study we proposed the introduction of a 6-aminohexanoic acid (Ahx) linker between the HYNIC chelator and lactam cyclized peptide cycMSH4-13 to reduce steric hindrance and improve the melanoma targeting and imaging proprieties of the radiolabeled peptide...
December 6, 2016: Anti-cancer Agents in Medicinal Chemistry
Valérie Vingtdeux, Haitian Zhao, Pallavi Chandakkar, Christopher M Acker, Peter Davies, Philippe Marambaud
Strategies aimed at reducing cerebral accumulation of the amyloid-β (Aβ) peptides have therapeutic potential in Alzheimer's disease (AD). Aβ immunization has proven to be effective at promoting Aβ clearance in animal models but adverse effects have hampered its clinical evaluation. The first anti-Aβ immunization clinical trial, which assessed a full-length Aβ1-42 vaccine, increased the risk of encephalitis most likely because of autoimmune pro-inflammatory T helper 1 (Th1) response against all forms of Aβ...
November 28, 2016: Molecular Medicine
A Ramesh Babu, G Raju, C Purna Chander, B Shoban Babu, R Srinivas, G V M Sharma
A new class of Boc-N-protected hybrid peptides derived from L- Ala and ε(6)-Caa (L-Ala = L-Alanine, Caa = C-linked carboamino acid derived from D-xylose) have been studied by positive ion electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS). MS(n) spectra of protonated and alkali-cationized hybrid peptides produce characteristic fragmentation involving the peptide backbone, the tert-butyloxycarbonyl (Boc) group, and the side chain. The dipeptide positional isomers are differentiated by the collision-induced dissociation (CID) of the protonated and alkali-cationized peptides...
2016: European Journal of Mass Spectrometry
Bo Mi Kim
Peptide-thioester is a pivotal intermediate for peptide ligation and N-, C-terminal cyclization. In this study, desired pathway and the side products of two C-terminal handles, hydroxyethylthiol (HET) and hydroxypropylthiol (HPT) are described in different conditions as well as kinetic studies. In addition, a new mechanism of C-terminal residue racemization is proposed on the basis of differentiation of products derived from the two C-terminal handles in preparing peptide thioesters through an acid-catalyzed tandem thiol switch, first by an intramolecular O-S acyl shift, and then by an intermolecular S-S exchange...
November 17, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Jonas Wilbs, Simon J Middendorp, Christian Heinis
Cyclic peptides binding to targets of interest can be generated efficiently with powerful in vitro display techniques, such as phage display or mRNA display. The cyclic peptide libraries screened with these methods are generated by altering in a combinatorial fashion the amino acid sequence of the peptides, the number of amino acids in the macrocycle rings, and the cyclization chemistry. A structural element that cannot easily be varied in the cyclic peptides is the backbone, which is built from amino acids, each of which contributes three atoms to the macrocyclic ring structure...
December 14, 2016: Chembiochem: a European Journal of Chemical Biology
Stefan J McCarver, Jennifer X Qiao, Joseph Carpenter, Robert M Borzilleri, Michael A Poss, Martin D Eastgate, Michael M Miller, David W C MacMillan
A method for the decarboxylative macrocyclization of peptides bearing N-terminal Michael acceptors has been developed. This synthetic method enables the efficient synthesis of cyclic peptides containing γ-amino acids and is tolerant of functionalities present in both natural and non-proteinogenic amino acids. Linear precursors ranging from 3 to 15 amino acids cyclize effectively under this photoredox method. To demonstrate the preparative utility of this method in the context of bioactive molecules, we synthesized COR-005, a somatostatin analogue that is currently in clinical trials...
January 16, 2017: Angewandte Chemie
Nir Qvit, Samuel J S Rubin, Travis J Urban, Daria Mochly-Rosen, Eric R Gross
Natural endogenously occurring peptides exhibit desirable medicinal properties, but are often limited in application by rapid proteolysis and inadequate membrane permeability. However, editing naturally occurring peptide sequences to develop peptidomimetic analogs created a promising class of therapeutics that can augment or inhibit molecular interactions. Here, we discuss a variety of chemical modifications, including l to d isomerization, cyclization, and unnatural amino acid substitution, as well as design strategies, such as attachment to cell-penetrating peptides, which are used to develop peptidomimetics...
November 14, 2016: Drug Discovery Today
Yuto Mifune, Hiroyuki Nakamura, Shinichiro Fuse
A cyclic RGD peptide was efficiently synthesized based on micro-flow, triphosgene-mediated peptide chain elongation and micro-flow photochemical macrolactamization. Our approach enabled a rapid (amidation for peptide chain elongation <5 s, macrolactamization <5 min) and clean (only one column chromatographic separation) synthesis of a cyclic peptide.
November 16, 2016: Organic & Biomolecular Chemistry
Zhenhong Zhu, Chi Zhang, Wenqi Song
The human transforming growth factor β (TGF-β)/bone morphogenic protein (BMP) signaling has been recognized as an attractive target to suppress fibroblast activation in osteonecrosis of the femoral head (ONFH). Here, we reported successful derivation of a self-inhibitory peptide from the crystal complex interface of TGF-β with its cognate receptor TβRI using rational molecular design and in vitro binding assay. Computational modeling suggested that the peptide possesses a large flexibility and would incur considerable entropy penalty...
November 9, 2016: Amino Acids
Deepika Mathur, Satya Prakash, Priya Anand, Harpreet Kaur, Piyush Agrawal, Ayesha Mehta, Rajesh Kumar, Sandeep Singh, Gajendra P S Raghava
Short half-life is one of the key challenges in the field of therapeutic peptides. Various studies have reported enhancement in the stability of peptides using methods like chemical modifications, D-amino acid substitution, cyclization, replacement of labile aminos acids, etc. In order to study this scattered data, there is a pressing need for a repository dedicated to the half-life of peptides. To fill this lacuna, we have developed PEPlife (, a manually curated resource of experimentally determined half-life of peptides...
November 7, 2016: Scientific Reports
Konstantin Andreev, Michael W Martynowycz, Andrey Ivankin, Mia L Huang, Ivan Kuzmenko, Mati Meron, Binhua Lin, Kent Kirshenbaum, David Gidalevitz
The peptidomimetic approach has emerged as a powerful tool for overcoming the inherent limitations of natural antimicrobial peptides, where the therapeutic potential can be improved by increasing the selectivity and bioavailability. Restraining the conformational flexibility of a molecule may reduce the entropy loss upon its binding to the membrane. Experimental findings demonstrate that the cyclization of linear antimicrobial peptoids increases their bactericidal activity against Staphylococcus aureus while maintaining high hemolytic concentrations...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Daniel P Dowling, Yan Kung, Anna K Croft, Koli Taghizadeh, Wendy L Kelly, Christopher T Walsh, Catherine L Drennan
Epothilones are thiazole-containing natural products with anticancer activity that are biosynthesized by polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) enzymes EpoA-F. A cyclization domain of EpoB (Cy) assembles the thiazole functionality from an acetyl group and l-cysteine via condensation, cyclization, and dehydration. The PKS carrier protein of EpoA contributes the acetyl moiety, guided by a docking domain, whereas an NRPS EpoB carrier protein contributes l-cysteine. To visualize the structure of a cyclization domain with an accompanying docking domain, we solved a 2...
November 1, 2016: Proceedings of the National Academy of Sciences of the United States of America
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