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https://www.readbyqxmd.com/read/28526710/gbt1118-a-potent-allosteric-modifier-of-hemoglobin-oxygen-affinity-increases-tolerance-to-severe-hypoxia-in-mice
#1
Kobina Dufu, Ozlem Yalcin, Eilleen Sy Ao-Ieong, Athiwat Hutchaleelala, Qing Xu, Zhe Li, Nicholas Vlahakis, Donna Oksenberg, Josh Lehrer-Graiwer, Pedro Cabrales
Adaptation to hypoxia requires compensatory mechanisms that affect oxygen (O2) transport and utilization. Decreased hemoglobin (Hb)-O2 affinity is considered part of the physiological adaptive process to chronic hypoxia. This manuscript explores the hypothesis that increased Hb-O2 affinity can complement acute physiological responses to hypoxia by increasing O2 uptake and delivery when compared to normal Hb-O2 affinity during acute severe hypoxia. To test this hypothesis, mice Hb-O2 affinity was increased via oral administration of 70 or 140 mg/kg GBT1118...
May 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28526474/recent-updates-on-third-generation-egfr-inhibitors-and-emergence-of-fourth-generation-egfr-inhibitors-to-combat-c797s-resistance
#2
REVIEW
Harun Patel, Rahul Pawara, Azim Ansari, Sanjay Surana
EGFR T790M mutation leads to resistance to most of clinically available EGFR TKIs. Third-generation EGFR TKIs against the T790M mutation have been in active clinical development, which includes osimertinib, rociletinib, HM61713, ASP8273, EGF816, and PF-06747775. On the other hand recently EGFR C797S mutation was reported to be a leading mechanism of resistance to the third-generation inhibitors. The C797S mutation appears to be an ideal target for overcoming the acquired resistance to the third generation inhibitors...
May 11, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28525268/rational-design-of-novel-allosteric-dihydrofolate-reductase-inhibitors-showing-antibacterial-effects-on-drug-resistant-e-coli-escape-variants
#3
Bharath Srinivasan, João V Rodrigues, Sam Tonddast-Navaei, Eugene Shakhnovich, Jeffrey Skolnick
In drug-discovery, systematic variations of substituents on a common scaffold and bioisosteric replacements are often used to generate diversity and obtain molecules with better biological effects. However, this could saturate the small-molecule diversity pool resulting in drug-resistance. On the other hand, conventional drug-discovery relies on targeting known pockets on protein surfaces leading to drug resistance by mutations of critical pocket residues. Here, we present a two-pronged strategy of designing novel drugs that target unique pockets on a protein's surface to overcome the above problems...
May 19, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28524849/structural-basis-for-conductance-through-tric-cation-channels
#4
Min Su, Feng Gao, Qi Yuan, Yang Mao, De-Lin Li, Youzhong Guo, Cheng Yang, Xiao-Hui Wang, Renato Bruni, Brian Kloss, Hong Zhao, Yang Zeng, Fa-Ben Zhang, Andrew R Marks, Wayne A Hendrickson, Yu-Hang Chen
Mammalian TRICs function as K(+)-permeable cation channels that provide counter ions for Ca(2+) handling in intracellular stores. Here we describe the structures of two prokaryotic homologues, archaeal SaTRIC and bacterial CpTRIC, showing that TRIC channels are symmetrical trimers with transmembrane pores through each protomer. Each pore holds a string of water molecules centred at kinked helices in two inverted-repeat triple-helix bundles (THBs). The pores are locked in a closed state by a hydrogen bond network at the C terminus of the THBs, which is lost when the pores assume an open conformation...
May 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28523095/therapeutic-advantage-of-the-positive-allosteric-modulators-of-the-gaba-b-receptor
#5
EDITORIAL
Ahmed F Abdel-Magid
No abstract text is available yet for this article.
May 11, 2017: ACS Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28522638/a-self-consistent-structural-perturbation-approach-for-determining-the-magnitude-and-extent-of-allosteric-coupling-in-proteins
#6
Nandakumar Rajasekaran, Athi N Naganathan
Elucidating the extent of energetic coupling between residues in single-domain proteins, a fundamental determinant of allostery, information transfer and folding cooperativity, has remained a grand challenge. While several sequence- and structure-based approaches have been proposed, a self-consistent description that is simultaneously compatible with unfolding thermodynamics is lacking. We had recently developed a simple structural perturbation protocol that captures the changes in thermodynamic stabilities induced by point mutations within the protein interior...
May 18, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28522547/a-regulatory-hierarchy-of-the-arabidopsis-branched-chain-amino-acid-metabolic-network
#7
Anqi Xing, Robert L Last
The branched-chain amino acids (BCAAs) Ile, Val and Leu are essential nutrients that humans and other animals obtain from plants. However, total and relative amounts of plant BCAAs rarely match animal nutritional needs, and improvement requires a better understanding of the mechanistic basis for BCAA homeostasis. We present an in vivo regulatory model of BCAA homeostasis derived from analysis of feedback-resistant Arabidopsis thaliana mutants for the three allosteric committed enzymes in the biosynthetic network: threonine deaminase (also named L-O-methylthreonine resistant 1, OMR1), acetohydroxyacid synthase small subunit 2 (AHASS2) and isopropylmalate synthase 1 (IPMS1)...
May 18, 2017: Plant Cell
https://www.readbyqxmd.com/read/28522347/functional-analysis-of-tcctlp-5c2-a-chymotrypsin-like-serine-protease-needed-for-molting-in-tribolium-castaneum
#8
Daniel Albaum, Gunnar Broehan, Subbaratnam Muthukrishnan, Hans Merzendorfer
In a previous study, we have characterized a gene family encoding chymotrypsin-like proteases from the red flour beetle, Tribolium castaneum (TcCTLPs). We identified 14 TcCTLP genes that were predominantly expressed in the midgut, where they presumably function in digestion. Two genes (TcCTLP-6C and TcCTLP-5C2), however, additionally showed considerable expression in the carcass, and RNAi studies demonstrated that they are required for molting (Broehan et al., 2010; Insect Biochem. Mol. Biol 40, 274-83). Thus, the enzyme has distinct functions in different physiological environments...
May 15, 2017: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28522253/challenges-in-the-development-of-an-m4-pam-preclinical-candidate-the-discovery-sar-and-in-vivo-characterization-of-a-series-of-3-aminoazetidine-derived-amides
#9
James C Tarr, Michael R Wood, Meredith J Noetzel, Jeanette L Bertron, Rebecca L Weiner, Alice L Rodriguez, Atin Lamsal, Frank W Byers, Sichen Chang, Hyekyung P Cho, Carrie K Jones, Colleen M Niswender, Michael W Wood, Nicholas J Brandon, Mark E Duggan, P Jeffrey Conn, Thomas M Bridges, Craig W Lindsley
This letter details the continued chemical optimization of a novel series of M4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core by incorporating a 3-amino azetidine amide moiety. The analogs described within this work represent the most potent M4 PAMs reported for this series to date. The SAR to address potency, clearance, subtype selectivity, CNS exposure, and P-gp efflux are described. This work culminated in the discovery of VU6000918, which demonstrated robust efficacy in a rat amphetamine-induced hyperlocomotion reversal model at a minimum efficacious dose of 0...
May 6, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28521704/dopamine-d2-receptors-dimers-how-can-we-pharmacologically-target-them
#10
Marco Carlia, Shivakumar Kolachalam, Stefano Aringhieri, Mario Rossib, Luca Giovannini, Roberto Maggio, Marco Scarselli
Dopamine D2 and D3 receptors are important pharmacological targets in Schizophrenia and Parkinson's disease. Intriguingly, many studies have shown that they form homo- and heterodimers, and they can be targeted in specific tissues with new drugs. In this direction, many efforts have been made to develop new molecules that are able to interact with these receptor dimeric complexes. Among various strategies for targeting dopamine receptors dimers, two distinct classes of compounds, such as bivalent and bitopic ligands, have gained particular attention and their use in pharmacology looks promising...
May 18, 2017: Current Neuropharmacology
https://www.readbyqxmd.com/read/28521115/anticonvulsant-profile-of-the-neuroactive-steroid-sge-516-in-animal-models
#11
Rebecca S Hammond, Alison L Althaus, Michael A Ackley, Carla Maciag, Gabriel Martinez Botella, Francesco G Salituro, Albert J Robichaud, James J Doherty
Despite the availability of multiple antiepileptic drugs (AED), failure to adequately control seizures is a challenge for approximately one third of epilepsy patients, and new therapies with a differentiated mechanism of action are needed. The neuroactive steroid, SGE-516, is a positive allosteric modulator of both gamma- and delta-containing GABAA receptors. This broad GABAA receptor activity differentiates neuroactive steroids like SGE-516 from benzodiazepines, a class of anticonvulsants which have been shown in vitro to selectively target gamma-subunit containing GABAA receptors...
May 7, 2017: Epilepsy Research
https://www.readbyqxmd.com/read/28520841/chronic-inflammatory-pain-impairs-mglur5-mediated-depolarization-induced-suppression-of-excitation-in-the-anterior-cingulate-cortex
#12
Baolin Guo, Jiaqi Wang, Han Yao, Keke Ren, Jing Chen, Jing Yang, Guohong Cai, Haiying Liu, Yunlong Fan, Wenting Wang, Shengxi Wu
The anterior cingulate cortex (ACC) is a critical hub for nociceptive perception and pain-related anxiety. Long-term synaptic plasticity in ACC was found to be important for chronic inflammatory pain and pain-related anxiety. As short-term synaptic plasticity, depolarization-induced suppression of excitation (DSE) is involved in several conditions, such as chronic stress, epilepsy, and autism. However, it is still unknown whether DSE in the ACC is involved in the central sensitization of pain and anxiety. Using a whole-cell patch clamp, calcium imaging, western blot, and behavioral testing, we found that DSE was induced by a 2 s depolarization in postsynaptic pyramidal cells in ACC...
May 17, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28520402/catch-and-release-engineered-allosterically-regulated-%C3%AE-roll-peptides-enable-on-off-biomolecular-recognition
#13
Beyza Bulutoglu, Kevin Dooley, Géza R Szilvay, Mark Blenner, Scott Banta
Alternative scaffolds for biomolecular recognition are being developed to overcome some of the limitations associated with immunoglobulin domains. The repeat-in-toxin (RTX) domain is a repeat protein sequence that reversibly adopts the β-roll secondary structure motif specifically upon calcium binding. This conformational change was exploited for controlled biomolecular recognition. Using ribosome display, an RTX peptide library was selected to identify binders to a model protein, lysozyme, exclusively in the folded state of the peptide...
May 18, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28517938/glutamate-ligation-in-the-ni-ii-and-co-ii-responsive-escherichia-coli-transcriptional-regulator-rcnr
#14
Carolyn E Carr, Francesco Musiani, Hsin-Ting Huang, Peter T Chivers, Stefano Ciurli, Michael J Maroney
Escherichia coli RcnR (resistance to cobalt and nickel regulator, EcRcnR) is a metal-responsive repressor of the genes encoding the Ni(II) and Co(II) exporter proteins RcnAB by binding to PRcnAB. The DNA binding affinity is weakened when the cognate ions Ni(II) and Co(II) bind to EcRcnR in a six-coordinate site that features a (N/O)5S ligand donor-atom set in distinct sites: while both metal ions are bound by the N terminus, Cys35, and His64, Co(II) is additionally bound by His3. On the other hand, the noncognate Zn(II) and Cu(I) ions feature a lower coordination number, have a solvent-accessible binding site, and coordinate protein ligands that do not include the N-terminal amine...
May 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28516764/an-autoinhibitory-role-for-the-pleckstrin-homology-domain-of-itk-and-its-interplay-with-canonical-phospholipid-recognition
#15
Sujan Devkota, Raji E Joseph, Scott E Boyken, D Bruce Fulton, Amy H Andreotti
Pleckstrin homology (PH) domains are well known as phospholipid binding modules yet evidence is mounting that PH domain function extends beyond lipid recognition. In the current work, we characterize a protein binding function for the PH domain of Interleukin-2-inducible tyrosine kinase (ITK), an immune cell specific signaling protein that belongs to the TEC family of non-receptor tyrosine kinases. Its N-terminal Pleckstrin homology (PH) domain is a well characterized lipid-binding module that localizes ITK to the membrane via phosphatidylinositol (3,4,5)-trisphosphate (PIP3) binding...
May 18, 2017: Biochemistry
https://www.readbyqxmd.com/read/28514449/human-glp-1-receptor-transmembrane-domain-structure-in-complex-with-allosteric-modulators
#16
Gaojie Song, Dehua Yang, Yuxia Wang, Chris de Graaf, Qingtong Zhou, Shanshan Jiang, Kaiwen Liu, Xiaoqing Cai, Antao Dai, Guangyao Lin, Dongsheng Liu, Fan Wu, Yiran Wu, Suwen Zhao, Li Ye, Gye Won Han, Jesper Lau, Beili Wu, Michael A Hanson, Zhi-Jie Liu, Ming-Wei Wang, Raymond C Stevens
The glucagon-like peptide-1 receptor (GLP-1R) and the glucagon receptor (GCGR) are members of the secretin-like class B family of G-protein-coupled receptors (GPCRs) and have opposing physiological roles in insulin release and glucose homeostasis. The treatment of type 2 diabetes requires positive modulation of GLP-1R to inhibit glucagon secretion and stimulate insulin secretion in a glucose-dependent manner. Here we report crystal structures of the human GLP-1R transmembrane domain in complex with two different negative allosteric modulators, PF-06372222 and NNC0640, at 2...
May 17, 2017: Nature
https://www.readbyqxmd.com/read/28513578/crystal-structure-of-a-multi-domain-human-smoothened-receptor-in-complex-with-a-super-stabilizing-ligand
#17
Xianjun Zhang, Fei Zhao, Yiran Wu, Jun Yang, Gye Won Han, Suwen Zhao, Andrii Ishchenko, Lintao Ye, Xi Lin, Kang Ding, Venkatasubramanian Dharmarajan, Patrick R Griffin, Cornelius Gati, Garrett Nelson, Mark S Hunter, Michael A Hanson, Vadim Cherezov, Raymond C Stevens, Wenfu Tan, Houchao Tao, Fei Xu
The Smoothened receptor (SMO) belongs to the Class Frizzled of the G protein-coupled receptor (GPCR) superfamily, constituting a key component of the Hedgehog signalling pathway. Here we report the crystal structure of the multi-domain human SMO, bound and stabilized by a designed tool ligand TC114, using an X-ray free-electron laser source at 2.9 Å. The structure reveals a precise arrangement of three distinct domains: a seven-transmembrane helices domain (TMD), a hinge domain (HD) and an intact extracellular cysteine-rich domain (CRD)...
May 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28512203/the-mechanism-of-activation-of-irak1-and-irak4-by-interleukin-1-and-toll-like-receptor-agonists
#18
Stefan Vollmer, Sam Strickson, Tinghu Zhang, Nathanael Gray, Katherine Lee, Vikram Rao, Philip Cohen
We have developed the first assays that measure the protein kinase activities of Interleukin-1 Receptor Associated Kinase 1 (IRAK1) and IRAK4 reliably in human cell extracts, by employing Pellino1 as a substrate in conjunction with specific pharmacological inhibitors of IRAK1 and IRAK4. We exploited these assays to show that IRAK4 was constitutively active and that its intrinsic activity towards Pellino1 was not increased significantly by stimulation with interleukin-1 (IL-1) in IL-1R-expressing HEK293 cells, Pam3Csk4-stimulated human THP1 monocytes or primary human macrophages...
May 16, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28512030/discovery-of-potent-and-orally-active-1-4-disubstituted-indazoles-as-novel-allosteric-glucokinase-activators
#19
Zacharia S Cheruvallath, Stephen L Gwaltney, Mark Sabat, Mingnam Tang, Haixia Wang, Andy Jennings, David Hosfield, Bumsup Lee, Yiqin Wu, Petro Halkowycz, Charles E Grimshaw
Guided by co-crystal structural information obtained from a different series we were exploring, a scaffold morphing and SBDD approach led to the discovery of the 1,4-disubstituted indazole series as a novel class of GKAs that potently activate GK in enzyme and cell assays. anti-diabetic OGTT efficacy was demonstrated with 29 in a rodent models of type 2 diabetes.
April 13, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28510428/statistical-analysis-and-prediction-of-covalent-ligand-targeted-cysteine-residues
#20
Weilin Zhang, Jianfeng Pei, Luhua Lai
Targeted covalent compounds or drugs have good potency as they can bind to a specific target for a long time with low doses. Most currently known covalent ligands were discovered by chance or by modifying existing non-covalent compounds to make them covalently attached to a nearby reactive residue. Computational methods for novel covalent ligand binding prediction are highly demanded. We performed statistical analysis on protein complexes with covalent ligands attached to cysteine residues. We found that covalent modified cysteine residues have unique features compared to those not attached to covalent ligands, including lower pKa, higher exposure and higher ligand binding affinity...
May 16, 2017: Journal of Chemical Information and Modeling
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