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Protein lipid interaction

Peter G Adams, Cvetelin Vasilev, C Neil Hunter, Matthew P Johnson
Light-Harvesting Complex II (LHCII) is a chlorophyll-protein antenna complex that efficiently absorbs solar energy and transfers electronic excited states to photosystems I and II. Under excess light intensity LHCII can adopt a photoprotective state in which excitation energy is safely dissipated as heat, a process known as Non-Photochemical Quenching (NPQ). In vivo NPQ is triggered by combinatorial factors including transmembrane ΔpH, PsbS protein and LHCII-bound zeaxanthin, leading to dramatically shortened LHCII fluorescence lifetimes...
June 18, 2018: Biochimica et Biophysica Acta
Barun Kumar Maity, Vicky Vishvakarma, Dayana Surendran, Anoop Rawat, Anirban Das, Shreya Pramanik, Najmul Arfin, Sudipta Maiti
Structure-based 'rational' drug-design strategies fail for diseases associated with intrinsically disordered proteins (IDPs). However, structural disorder allows large amplitude spontaneous intramolecular dynamics in a protein. We demonstrate a method that exploits this dynamics to provide quantitative information about the degree of interaction of an IDP with other molecules. A candidate ligand molecule may not bind strongly, but even momentary interactions can be expected to perturb the fluctuations. We measure the amplitude and frequency of the equilibrium fluctuations of fluorescently labeled small oligomers of hIAPP (an IDP associated with Type II diabetes) in a physiological solution, using nanosecond fluorescence cross-correlation spectroscopy...
June 21, 2018: Biochemistry
Momoko Hamano, Yurina Haraguchi, Tomoko Sayano, Chong Zyao, Yashiho Arimoto, Yui Kawano, Kazuki Moriyasu, Miyako Udono, Yoshinori Katakura, Takuya Ogawa, Hisanori Kato, Shigeki Furuya
l-Serine (l-Ser) is a necessary precursor for the synthesis of proteins, lipids, glycine, cysteine, d-serine, and tetrahydrofolate metabolites. Low l-Ser availability activates stress responses and cell death; however, the underlying molecular mechanisms remain unclear. l-Ser is synthesized de novo from 3-phosphoglycerate with 3-phosphoglycerate dehydrogenase (Phgdh) catalyzing the first reaction step. Here, we show that l-Ser depletion raises intracellular H2 O2 levels and enhances vulnerability to oxidative stress in Phgdh-deficient mouse embryonic fibroblasts...
June 2018: FEBS Open Bio
Joseph R Iacona, Nicholas J Monteleone, Carol S Lutz
Arachidonic acid (AA) can be converted into prostaglandins (PGs) or leukotrienes (LTs) by the enzymatic actions of cyclooxygenases (COX-1 and COX-2) or 5-lipoxygenase (5-LO), respectively. PGs and LTs are lipid signaling molecules that have been implicated in various diseases, including multiple cancers. 5-LO and its activating protein (FLAP) work together in the first two conversion steps of LT production. Previous work has suggested a role for LTs in cancer development and progression. MicroRNAs (miRNAs) are small RNA molecules that negatively regulate gene expression post-transcriptionally, and have previously been shown to be involved in cancer...
June 1, 2018: Oncotarget
Michael Wiebrands, Chris J Malajczuk, Andrew J Woods, Andrew L Rohl, Ricardo L Mancera
Molecular graphics systems are visualization tools which, upon integration into a 3D immersive environment, provide a unique virtual reality experience for research and teaching of biomolecular structure, function and interactions. We have developed a molecular structure and dynamics application, the Molecular Dynamics Visualization tool, that uses the Unity game engine combined with large scale, multi-user, stereoscopic visualization systems to deliver an immersive display experience, particularly with a large cylindrical projection display...
June 21, 2018: Journal of Integrative Bioinformatics
Günter Schwarzmann
For the physicochemical studies aimed at elucidating the dynamic of gangliosides in membranes and their interaction with proteins and membrane lipids, photoactivatable and paramagnetic ganglioside derivatives have proved to be invaluable tools. Here, protocols for the synthesis of such ganglioside derivatives are described. These derivatives bear in their ceramide portion either a highly photoreactive (3-trifluoromethyl)phenyldiazirinyl- or a spin active doxyl-labeled acyl chain in place of their natural acyl chain...
2018: Methods in Molecular Biology
Günter Schwarzmann
Labeled gangliosides are invaluable tools to study their transport and metabolism within cells as well as to determine their distribution in membranes, and their interaction with membrane lipids and proteins. Here I describe established procedures to synthesize ganglioside derivatives with a fluorescent tag either attached to its sialooligosaccharide or ceramide portion. These procedures are chosen as to minimize the integrity of the ganglioside molecule and hence, to leave their native skeleton formally intact...
2018: Methods in Molecular Biology
Kazuhisa Iwabuchi
Although individuals are constantly exposed to infectious agents, these agents are generally resisted by the innate and acquired immune systems. Both the innate and acquired immune systems protect against invading organisms, but they differ functionally in several ways. The innate immune system is the body's inborn defense mechanism and the first line of defense against invading organisms, such as bacteria, fungi, and viruses. Glycosphingolipids (GSLs), which are expressed on the outer leaflet of plasma membranes (Murate et al...
2018: Methods in Molecular Biology
Jiangtong Peng, Yutian Li, Xiaohong Wang, Shan Deng, Jenna Holland, Emily Yates, Jing Chen, Haitao Gu, Kobina Essandoh, Xingjiang Mu, Boyu Wang, Robert K McNamara, Tianqing Peng, Anil G Jegga, Tiemin Liu, Takahisa Nakamura, Kai Huang, Diego Perez-Tilve, Guo-Chang Fan
Exposure to cold temperature is well known to upregulate heat shock protein (Hsp) expression and recruit and/or activate brown adipose tissue and beige adipocytes in humans and animals. However, whether and how Hsps regulate adipocyte function for energy homeostatic responses is poorly understood. Here, we demonstrate a critical role of Hsp20 as a negative regulator of adipocyte function. Deletion of Hsp20 enhances non-shivering thermogenesis and suppresses inflammatory responses, leading to improvement of glucose and lipid metabolism under both chow diet and high-fat diet conditions...
June 19, 2018: Cell Reports
Marcin Krupka, Marta Sobrinos-Sanguino, Mercedes Jiménez, Germán Rivas, William Margolin
ZipA is an essential cell division protein in Escherichia coli Together with FtsA, ZipA tethers dynamic polymers of FtsZ to the cytoplasmic membrane, and these polymers are required to guide synthesis of the cell division septum. This dynamic behavior of FtsZ has been reconstituted on planar lipid surfaces in vitro , visible as GTP-dependent chiral vortices several hundred nanometers in diameter, when anchored by FtsA or when fused to an artificial membrane binding domain. However, these dynamics largely vanish when ZipA is used to tether FtsZ polymers to lipids at high surface densities...
June 19, 2018: MBio
Graziele Freitas de Bem, Cristiane Aguiar Costa, Izabelle Barcellos Santos, Viviane da Silva Cristino Cordeiro, Lenize Costa Reis Marins de Carvalho, Marcelo Augusto Vieira de Souza, Ricardo de Andrade Soares, Pergentino José da Cunha Sousa, Dayane Teixeira Ognibene, Angela Castro Resende, Roberto Soares de Moura
A growing body of evidence suggests a protective role of polyphenols and exercise training on the disorders of type 2 diabetes mellitus (T2DM). We aimed to assess the effect of the açaí seed extract (ASE) associated with exercise training on diabetic complications induced by high-fat (HF) diet plus streptozotocin (STZ) in rats. Type 2 diabetes was induced by feeding rats with HF diet (55% fat) for 5 weeks and a single dose of STZ (35 mg/kg i.p.). Control (C) and Diabetic (D) animals were subdivided into four groups each: Sedentary, Training, ASE Sedentary, and ASE Training...
2018: PloS One
C Zhao, A Y-H Wu, X Yu, Y Gu, Y Lu, X Song, N An, Y Zhang
Airway remodeling manifested by hyperplasia of airway smooth muscle cells (ASMCs) and other structural and functional changes is a pathological condition in asthma not addressed by current treatment. Ca2+ signaling is crucial for ASMC proliferation. Inositol-1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR) mediate Ca2+ release from endoplasmic reticulum/sarcoplasmic reticulum (ER/SR). Upon sensing the depletion of Ca2+ in ER/SR, stromal interaction molecule 1 (STIM1) aggregates and redistributes at the microdomain of ER/SR-plasma membrane (PM) and activates Orai1, a component of the store-operated Ca2+ (SOC) channels, to initiate Ca2+ influx...
April 2018: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
Jing Hou, Heping Zheng, Wen-Shyong Tzou, David R Cooper, Maksymilian Chruszcz, Mahendra D Chordia, Keehwan Kwon, Marek Grabowski, Wladek Minor
Vibrio cholerae, the causative pathogen of the life-threatening infection cholera, encodes two copies of β-ketoacyl-ACP synthase III (vcFabH1 and vcFabH2). vcFabH1 and vcFabH2 are pathogenic proteins associated with fatty acid synthesis, lipid metabolism, and potential applications in biofuel production. Our biochemical assays characterize vcFabH1 as exhibiting specificity for acetyl-CoA and CoA thioesters with short acyl chains, similar to that observed for FabH homologs found in most Gram-negative bacteria...
June 19, 2018: FEBS Journal
Eleri Hughes, John M Griffin, Michael P Coogan, David A Middleton
Fluorine is often incorporated into the aromatic moieties of synthetic bioactive molecules such as pharmaceuticals and disease diagnostics in order to alter their physicochemical properties. Fluorine substitution may increase a molecule's lipophilicity, thereby enabling its diffusion across cell membranes to enhance bioavailability or to exert a direct physiological effect from within the lipid bilayer. Understanding the structure, dynamics and orientation of fluoroaromatic molecules in lipid bilayers can provide useful insight into the effect of fluorine on their mode of action, and their interactions with membrane-embedded targets or efflux proteins...
June 19, 2018: Physical Chemistry Chemical Physics: PCCP
D Caputo, M Cartillone, C Cascone, D Pozzi, L Digiacomo, S Palchetti, G Caracciolo, R Coppola
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) early diagnosis is  crucial  and new, cheap and user-friendly techniques for biomarker identification  are  needed. "Protein corona" (PC) is emerging a new bio-interface potentially useful in tumor early diagnosis. In a previous investigation, we showed that relevant differences between the  protein patterns of  PCs formed on lipid NPs after exposure to PDAC and non-cancer plasma  samples exist. To extend that research, We performed this pilot study to investigate the effect of PDAC tumor size and distant metastases on PC composition...
June 12, 2018: Pancreatology: Official Journal of the International Association of Pancreatology (IAP) ... [et Al.]
Jolanta Zegarlińska, Magda Piaścik, Aleksander F Sikorski, Aleksander Czogalla
Phosphatidic acid (PA) is the simplest glycerophospholipid naturally occurring in living organisms, and even though its content among other cellular lipids is minor, it is drawing more and more attention due to its multiple biological functions. PA is a precursor for other phospholipids, acts as a lipid second messenger and, due to its structural properties, is also a modulator of membrane shape. Although much is known about interaction of PA with its effectors, the molecular mechanisms remain unresolved to a large degree...
2018: Acta Biochimica Polonica
Taylor Pini, Tamara Leahy, Simon P de Graaf
Semen cryopreservation is an important tool for artificial breeding, species conservation and human reproductive medicine. However, sublethal freezing damage remains an important limitation of the cryopreservation process, inevitably leading to reduced fertility in vivo. This review explores several facets of sublethal freezing damage, touching on cryocapacitation, the generation of reactive oxygen species and alterations to sperm proteins, lipids and sugars. The effects of sublethal freezing damage on sperm performance in vivo are also discussed, examining fertile lifespan and interaction with female reproductive tract immune cells, mucus and oviductal cells...
June 11, 2018: Theriogenology
Patrick C A van der Wel
Various recent developments in solid-state nuclear magnetic resonance (ssNMR) spectroscopy have enabled an array of new insights regarding the structure, dynamics, and interactions of biomolecules. In the ever more integrated world of structural biology, ssNMR studies provide structural and dynamic information that is complementary to the data accessible by other means. ssNMR enables the study of samples lacking a crystalline lattice, featuring static as well as dynamic disorder, and does so independent of higher-order symmetry...
April 20, 2018: Emerging Topics in Life Sciences
Manuel U Ramirez, Elizabeth R Stirling, Nancy J Emenaker, David D Roberts, David R Soto-Pantoja
The metabolism of arachidonic acid and other polyunsaturated fatty acids produces eicosanoids, a family of biologically active lipids that are implicated in homeostasis and in several pathologies that involve inflammation. Inflammatory processes mediated by eicosanoids promote carcinogenesis by exerting direct effects on cancer cells and by affecting the tumor microenvironment. Therefore, understanding how eicosanoids mediate cancer progression may lead to better approaches and chemopreventive strategies for the treatment of cancer...
June 16, 2018: Cancer Metastasis Reviews
Ismahene Dahmane, Caroline Montagner, André Matagne, Shrinivas Dumbre, Piet Herdewijn, Mohammed Terrak
Peptidoglycan glycosyltransferases (GTase) of family 51 are essential enzymes for the synthesis of the glycan chains of the bacterial cell wall. They are considered potential antibacterial target, but discovery of inhibitors was hampered so far by the lack of efficient and affordable screening assay. Here we used Staphylococcus aureus MtgA to introduce a single tryptophan reporter residue in selected positions flanking the substrates binding cavity of the protein. We selected a mutant (Y181W) that shows strong fluorescence quenching in the presence of moenomycin A and two lipid II analogs inhibitors...
June 14, 2018: Biochimie
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