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Structures of membrane protein

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https://www.readbyqxmd.com/read/28431242/structural-and-functional-analysis-of-a-%C3%AE-2-adrenergic-receptor-complex-with-grk5
#1
Konstantin E Komolov, Yang Du, Nguyen Minh Duc, Robin M Betz, João P G L M Rodrigues, Ryan D Leib, Dhabaleswar Patra, Georgios Skiniotis, Christopher M Adams, Ron O Dror, Ka Young Chung, Brian K Kobilka, Jeffrey L Benovic
The phosphorylation of agonist-occupied G-protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) functions to turn off G-protein signaling and turn on arrestin-mediated signaling. While a structural understanding of GPCR/G-protein and GPCR/arrestin complexes has emerged in recent years, the molecular architecture of a GPCR/GRK complex remains poorly defined. We used a comprehensive integrated approach of cross-linking, hydrogen-deuterium exchange mass spectrometry (MS), electron microscopy, mutagenesis, molecular dynamics simulations, and computational docking to analyze GRK5 interaction with the β2-adrenergic receptor (β2AR)...
April 20, 2017: Cell
https://www.readbyqxmd.com/read/28431018/disulfide-bonds-enable-accelerated-protein-evolution
#2
Felix Feyertag, David Alvarez-Ponce
The different proteins of any proteome evolve at enormously different rates. What factors contribute to this variability, and to what extent, is still a largely open question. We hypothesized that disulfide bonds, by increasing protein stability, should make proteins' structures relatively independent of their amino acid sequences, thus acting as buffers of deleterious mutations and enabling accelerated sequence evolution. In agreement with this hypothesis, we observed that membrane proteins with disulfide bonds evolved 88% faster than those without disulfide bonds, and that extracellular proteins with disulfide bonds evolved 49% faster than those without disulfide bonds...
April 18, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28430797/effect-of-quinoline-based-1-2-3-triazole-and-its-structural-analogues-on-growth-and-virulence-attributes-of-candida-albicans
#3
Mohammad Irfan, Shadab Alam, Nikhat Manzoor, Mohammad Abid
Candida albicans, along with some other non-albicans Candida species, is a group of yeast, which causes serious infections in humans that can be both systemic and superficial. Despite the fact that extensive efforts have been put into the discovery of novel antifungal agents, the frequency of these fungal infections has increased drastically worldwide. In our quest for the discovery of novel antifungal compounds, we had previously synthesized and screened quinoline containing 1,2,3-triazole (3a) as a potent Candida spp inhibitor...
2017: PloS One
https://www.readbyqxmd.com/read/28430426/the-rosetta-all-atom-energy-function-for-macromolecular-modeling-and-design
#4
Rebecca Faye Alford, Andrew Leaver-Fay, Jeliazko R Jeliazkov, Matthew J O'Meara, Frank P DiMaio, Hahnbeom Park, Maxim V Shapovalov, P Douglas Renfrew, Vikram Khipple Mulligan, Kalli Kappel, Jason W Labonte, Michael Steven Pacella, Richard Bonneau, Philip Bradley, Roland L Dunbrack, Rhiju Das, David Baker, Brian Kuhlman, Tanja Kortemme, Jeffrey J Gray
Over the past decade, the Rosetta biomolecular modeling suite has informed diverse biological questions and engineering challenges ranging from interpretation of low-resolution structural data to design of nanomaterials, protein therapeutics, and vaccines. Central to Rosetta's success is the energy function: a model parameterized from small molecule and X-ray crystal structure data used to approximate the energy associated with each biomolecule conformation. This paper describes the mathematical models and physical concepts that underlie the latest Rosetta Energy Function, REF15...
April 21, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28430241/probing-the-germination-kinetics-of-ethanol-treated-bacillus-thuringiensis-spores
#5
Guiwen Wang, Huanjun Chen, Xiaochun Wang, Lixin Peng, Yuan Peng, Yong-Qing Li
Bacillus thuringiensis (Bt) is the most widely used microbial insecticide. To clarify the mechanism of bacterial resistance to ethanol toxicity, the present study investigated the effects of 70% (v/v) ethanol at a moderate temperature (65°C) on Bt spore germination by single-cell Raman spectroscopy and differential interference contrast microscopy. We found that over 80% of Bt spores were inviable after 30 min of treatment. Moreover, ethanol treatment affected spore germination; the time for initiation of rapid calcium dipicolinate (CaDPA) release (i...
April 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28429411/nanodiscs-for-inpharma-nmr-characterization-of-gpcrs-ligand-binding-to-the-human-a2a-adenosine-receptor
#6
Kai Fredriksson, Philip Lottmann, Sonja Hinz, Iounut Onila, Aliaksei Shymanets, Christian Harteneck, Christa E Müller, Christian Griesinger, Thomas E Exner
G-protein-coupled-receptors (GPCRs) are of fundamental importance for signal transduction through cell membranes. This makes them important drug targets, but structure-based drug design (SBDD) is still hampered by the limitations for structure determination of unmodified GPCRs. We show that the interligand NOEs for pharmacophore mapping (INPHARMA) method can provide valuable information on ligand poses inside the binding site of the unmodified human A2A adenosine receptor reconstituted in nanodiscs. By comparing experimental INPHARMA spectra with back-calculated spectra based on ligand poses obtained from molecular dynamics simulations, a complex structure for A2A R with the low-affinity ligand 3-pyrrolidin-1-ylquinoxalin-2-amine was determined based on the X-ray structure of ligand ZM-241,358 in complex with a modified A2A R...
April 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28429323/protein-targeting-to-the-plastid-of-euglena
#7
Dion G Durnford, Steven D Schwartzbach
The lateral transfer of photosynthesis between kingdoms through endosymbiosis is among the most spectacular examples of evolutionary innovation. Euglena, which acquired a chloroplast indirectly through an endosymbiosis with a green alga, represents such an example. As with other endosymbiont-derived plastids from eukaryotes, there are additional membranes that surround the organelle, of which Euglena has three. Thus, photosynthetic genes that were transferred from the endosymbiont to the host nucleus and whose proteins are required in the new plastid, are now faced with targeting and plastid import challenges...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28429276/enhancing-thermal-stability-of-a-highly-concentrated-insulin-formulation-with-pluronic-f-127-for-long-term-use-in-microfabricated-implantable-devices
#8
Jason Li, Michael K Chu, Brian Lu, Sako Mirzaie, Kuan Chen, Claudia R Gordijo, Oliver Plettenburg, Adria Giacca, Xiao Yu Wu
Development of highly concentrated formulations of protein and peptide drugs is a major challenge due to increased susceptibility to aggregation and precipitation. Numerous drug delivery systems including implantable and wearable controlled-release devices require thermally stable formulations with high concentrations due to limited device sizes and long-term use. Herein we report a highly concentrated insulin gel formulation (up to 80 mg/mL, corresponding to 2200 IU/mL), stabilized with a non-ionic amphiphilic triblock copolymer (i...
April 20, 2017: Drug Delivery and Translational Research
https://www.readbyqxmd.com/read/28428954/uncovering-the-roles-of-septins-in-cilia
#9
REVIEW
Oliva Palander, Maha El-Zeiry, William S Trimble
Septins are a family of GTP-binding proteins that associate with cellular membranes and the cytoskeleton. Their ability to polymerize into filamentous structures permits them to serve as diffusion barriers for membrane proteins and as multi-molecular scaffolds that recruit components of signaling pathways. At the cellular level, septins contribute to the regulation of numerous processes, including cytokinesis, cell polarity, cell migration, and many others. In this review, we discuss emerging evidence for roles of mammalian septins in the biogenesis and function of flagella and cilia, and how this may impact human diseases such as ciliopathies...
2017: Frontiers in Cell and Developmental Biology
https://www.readbyqxmd.com/read/28427443/benserazide-a-dopadecarboxylase-inhibitor-suppresses-tumor-growth-by-targeting-hexokinase-2
#10
Wei Li, Mengzhu Zheng, Shuangping Wu, Suyu Gao, Mei Yang, Zhimei Li, Qiuxia Min, Weiguang Sun, Lixia Chen, Guangya Xiang, Hua Li
BACKGROUND: Hexokinase (HK) is the rate-limiting enzyme in the first reaction of glycolysis. And Hexokinase 2 (HK2) is most closely related to malignant tumor which expresses at higher level compared with normal cells. HK2 plays a pivotal role in tumor initiation and maintenance, which provides a new target for cancer therapy. METHODS: Structure-based virtual ligand screening was used in hit identification from ZINC Drug Database. Microscale thermophoresis assay was performed to evaluate the binding affinity...
April 20, 2017: Journal of Experimental & Clinical Cancer Research: CR
https://www.readbyqxmd.com/read/28427235/catan-ionic-hybrid-lipidic-nano-carriers-for-enhanced-bioavailability-and-anti-tumor-efficacy-of-chemodrugs
#11
Bilin Liu, Dan He, Jianyong Wu, Quan Sun, Mi Zhang, Qunyou Tan, Yao Li, Jingqing Zhang
To date there has not been any report on catan-ionic hybrid lipidic nano-carriers, let alone a report on applying them to deliver insoluble anti-tumor drugs. Catan-ionic hybrid lipidic nano-carriers containing curcumin (CUR-C-HLN) inherit the merits of catan-ionic systems, hybrid lipidic systems and nano-structured carriers (the second-generation substitute of solid lipidic nano-systems). Catan-ionic surfactants increased microvesicle stabilization by producing unordered isometric clusters, enhanced absorptive amount as an inhibitor of enzyme and protein, improved tumor accumulation by cellular endocytosis and membranous fusion; hybrid lipids helped to obtain high drug content and low leakage by forming a less-organized matrix arrangement...
March 6, 2017: Oncotarget
https://www.readbyqxmd.com/read/28427058/dietary-selenium-or-zinc-supplementation-restores-brain-lipid-composition-and-membrane-fluidity-in-protein-undernourished-rats
#12
Olusegun L Adebayo, Bamidele A Salau, Rajat Sandhir, Gbenga A Adenuga
Studies have shown that protein undernutrition (PU) modifies the membrane lipid composition in the intestine and liver, as well as in plasma and other areas. However, there is limited information on the effect of PU on synaptosomal membrane lipid composition and fluidity and the protective role of selenium (Se) and zinc (Zn), which is a major focus of the present study. For 10 weeks, rats were fed diets containing 16% casein, which constituted the adequate protein diet, or 5% casein, representing the PU diet...
April 21, 2017: Developmental Neuroscience
https://www.readbyqxmd.com/read/28426751/the-role-of-microsporidian-polar-tube-protein-4-ptp4-in-host-cell-infection
#13
Bing Han, Valérie Polonais, Tatsuki Sugi, Rama Yakubu, Peter M Takvorian, Ann Cali, Keith Maier, Mengxian Long, Matthew Levy, Herbert B Tanowitz, Guoqing Pan, Frédéric Delbac, Zeyang Zhou, Louis M Weiss
Microsporidia have been identified as pathogens that have important effects on our health, food security and economy. A key to the success of these obligate intracellular pathogens is their unique invasion organelle, the polar tube, which delivers the nucleus containing sporoplasm into host cells during invasion. Due to the size of the polar tube, the rapidity of polar tube discharge and sporoplasm passage, and the absence of genetic techniques for the manipulation of microsporidia, study of this organelle has been difficult and there is relatively little known regarding polar tube formation and the function of the proteins making up this structure...
April 20, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28426203/tyrosine-kinase-activation-and-conformational-flexibility-lessons-from-src-family-tyrosine-kinases
#14
Yilin Meng, Matthew P Pond, Benoît Roux
Protein kinases are enzymes that catalyze the covalent transfer of the γ-phosphate of an adenosine triphosphate (ATP) molecule onto a tyrosine, serine, threonine, or histidine residue in the substrate and thus send a chemical signal to networks of downstream proteins. They are important cellular signaling enzymes that regulate cell growth, proliferation, metabolism, differentiation, and migration. Unregulated protein kinase activity is often associated with a wide range of diseases, therefore making protein kinases major therapeutic targets...
April 20, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28425709/beyond-structural-biology-to-functional-biology-solid-state-nmr-experiments-and-strategies-for-understanding-the-m2-proton-channel-conductance
#15
Huajun Qin, Yimin Miao, Timothy A Cross, Riqiang Fu
In terms of structural biology, solid-state NMR experiments and strategies have been well established for resonance assignments leading to the determination of three-dimensional structures of insoluble membrane proteins in their native-like environment. It is also known that NMR has the unique capabilities to characterize structure-function relationships of membrane-bound biological systems beyond structural biology. Here, we report on solid-state NMR experiments and strategies for extracting functional activities on a sub-msec time scale...
April 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28424773/septins-focus-cellular-growth-for-host-infection-by-pathogenic-fungi
#16
REVIEW
Michelle Momany, Nicholas J Talbot
One of the key challenges faced by microbial pathogens is invasion of host tissue. Fungal pathogens adopt a number of distinct strategies to overcome host cell defenses, including the development of specialized infection structures, the secretion of proteins that manipulate host responses or cellular organization, and the ability to facilitate their own uptake by phagocytic mechanisms. Key to many of these adaptations is the considerable morphogenetic plasticity displayed by pathogenic species. Fungal pathogens can, for example, shift their growth habit between non-polarized spores, or yeast-like cells, and highly polarized hyphal filaments...
2017: Frontiers in Cell and Developmental Biology
https://www.readbyqxmd.com/read/28422790/particle-based-delivery-of-the-hiv-envelope-protein
#17
Benedikt Asbach, Ralf Wagner
PURPOSE OF REVIEW: A major focus in HIV vaccine research is the development of suitable antigens that elicit broadly neutralizing antibody responses targeting HIV's envelope protein (Env). Delivery of Env in a repetitive manner on particle-based carriers allows higher avidity interactions and is therefore expected to efficiently engage B cells, thus leading to affinity maturation that results in superior antibody responses characterized by improved breadth, potency, and durability. This review summarizes current work that is evaluating diverse types of such particulate carriers for Env delivery...
May 2017: Current Opinion in HIV and AIDS
https://www.readbyqxmd.com/read/28422789/antigp41-membrane-proximal-external-region-antibodies-and-the-art-of-using-the-membrane-for-neutralization
#18
Nichole Cerutti, Juan Luis Loredo-Varela, Christophe Caillat, Winfried Weissenhorn
PURPOSE OF REVIEW: We summarize the latest research on the progress to understand the neutralizing epitopes present within the membrane proximal external region (MPER) of the HIV-1 fusion protein subunit gp41. RECENT FINDINGS: The HIV-1 fusion protein subunit gp41 contains a highly conserved sequence that is essential for membrane fusion and targeted by broadly neutralizing antibodies such as 2F5, 4E10, Z13e1, and 10E8. These antibodies recognize a linear gp41 epitope with high affinity, but require additional hydrophobic sequences present in their heavy chain CDR3 for neutralization...
May 2017: Current Opinion in HIV and AIDS
https://www.readbyqxmd.com/read/28422051/annexins-as-overlooked-regulators-of-membrane-trafficking-in-plant-cells
#19
REVIEW
Dorota Konopka-Postupolska, Greg Clark
Annexins are an evolutionary conserved superfamily of proteins able to bind membrane phospholipids in a calcium-dependent manner. Their physiological roles are still being intensively examined and it seems that, despite their general structural similarity, individual proteins are specialized toward specific functions. However, due to their general ability to coordinate membranes in a calcium-sensitive fashion they are thought to participate in membrane flow. In this review, we present a summary of the current understanding of cellular transport in plant cells and consider the possible roles of annexins in different stages of vesicular transport...
April 19, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28421167/iron-and-virulence-in-francisella-tularensis
#20
REVIEW
Girija Ramakrishnan
Francisella tularensis, the causative agent of tularemia, is a Gram-negative bacterium that infects a variety of cell types including macrophages, and propagates with great efficiency in the cytoplasm. Iron, essential for key enzymatic and redox reactions, is among the nutrients required to support this pathogenic lifestyle and the bacterium relies on specialized mechanisms to acquire iron within the host environment. Two distinct pathways for iron acquisition are encoded by the F. tularensis genome- a siderophore-dependent ferric iron uptake system and a ferrous iron transport system...
2017: Frontiers in Cellular and Infection Microbiology
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