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protein folding

Fernando J Sialana, Peter Gulyassy, Peter Májek, Evelina Sjöstedt, Viktor Kis, André C Müller, Elena L Rudashevskaya, Jan Mulder, Keiryn L Bennett, Gert Lubec
The molecular composition of synaptic signal transduction machineries shapes synaptic neurotransmission. The repertoire of receptors, transporters and channels (RTCs) comprises major signaling events in the brain. RTCs are conventionally studied by candidate immunohistochemistry and biochemistry, which are low throughput with resolution greatly affected by available immunoreagents and membrane interference. Therefore, a comprehensive resource of synaptic brain RTCs is still lacking. In particular, studies on the detergent-soluble synaptosomal fraction, known to contain transporters and channels, are limited...
October 19, 2016: Proteomics
Ashraf Kariminik, Ramin Yaghobi, Shahriar Dabiri
OBJECTIVES: It has been hypothesized that BK polyomavirus infection leads to nephropathy in kidney transplant patients via various plausible mechanisms, such as stimulation of chemokines. The CXCL11 gene may also play a role in BK polyomavirus-associated nephropathy. Our aim was to compare expression levels of CXCL11 in BK polyomavirus-infected versus noninfected kidney transplant patients with nephropathy and healthy controls. MATERIALS AND METHODS: We performed a cross-sectional study of 58 kidney transplant patients with the risk of BK polyomavirus infection; these patients were subgrouped as BK polyomavirus-infected (23 patients) and noninfected (35 patients)...
October 14, 2016: Experimental and Clinical Transplantation
Alberto Baggioli, Carlo A Cavallotti, Antonino Famulari
From proteins and peptides to semiconducting polymers, aliphatic chains on aromatic groups are recurring motifs in macromolecules from very diverse application fields. Fields in which molecular folding and packing determine the macroscopic physical properties that make such advanced materials appealing in the first place. Within each macromolecule, the intrinsic structure of each unit defines how it interacts with its neighbours, ultimately opening up or denying certain backbone conformations. This eventually also determines how macromolecules interact with each other...
October 18, 2016: Physical Chemistry Chemical Physics: PCCP
Jianhua Yang, Anna Joëlle Ruff, Stefanie Nicole Hamer, Feng Cheng, Ulrich Schwaneberg
Escherichia coli is a common host for recombinant protein production in which production titers are highly dependent on the employed expression system. Promoters are thereby a key element to control gene expression levels. In this study, a novel PLICable promoter toolbox was developed which enables in a single cloning step and after a screening experiment to identify out of ten IPTG-inducible promoters (T7, A3, lpp, tac, pac, Sp6, lac, npr, trc and syn) the most suitable one for high level protein production...
October 18, 2016: Biotechnology Journal
Cuiling Wu, Dan Liu, Xinghao Yang, Ribang Wu, Jiang Zhang, Jiafeng Huang, Hailun He
Pseudoalteromonas sp. CSN423, a marine strain, can express a major protease designated as E423 and it was secreted into the supernatant. To improve the protease E423 yield, Pseudoalteromonas sp. CSN423 was subjected to mutagenesis using UV irradiation. Mutant strain with 5.1-fold higher protease yield was isolated and named as Pseudoalteromonas sp. CSN423-M. Three protease bands were detected by zymography with casein as substrate, and results of mass spectrometry (MS) showed that two lower molecular weight protein bands were the same protease but with different mature forms...
October 17, 2016: Marine Biotechnology
Amanda L Mansouri, Laura N Grese, Erica L Rowe, James C Pino, S Chakra Chennubhotla, Arvind Ramanathan, Hugh M O'Neill, Valerie Berthelier, Christopher B Stanley
Proteins imparted with intrinsic disorder conduct a range of essential cellular functions. To better understand the folding and hydration properties of intrinsically disordered proteins (IDPs), we used osmotic stress to induce conformational changes in nuclear co-activator binding domain (NCBD) and activator for thyroid hormone and retinoid receptor (ACTR) separate from their mutual binding. Osmotic stress was applied by the addition of small and polymeric osmolytes, where we discovered that water contributions to NCBD folding always exceeded those for ACTR...
October 18, 2016: Molecular BioSystems
Shaozhou Zhu, Christopher D Fage, Julian D Hegemann, Andreas Mielcarek, Dushan Yan, Uwe Linne, Mohamed A Marahiel
Lasso peptides are a class of ribosomally synthesized and post-translationally modified peptides (RiPPs) with a unique lariat knot-like fold that endows them with extraordinary stability and biologically relevant activity. However, the biosynthetic mechanism of these fascinating molecules remains largely speculative. Generally, two enzymes (B for processing and C for cyclization) are required to assemble the unusual knot-like structure. Several subsets of lasso peptide gene clusters feature a "split" B protein on separate open reading frames (B1 and B2), suggesting distinct functions for the B protein in lasso peptide biosynthesis...
October 18, 2016: Scientific Reports
Kazuki Kawahara, Shinya Yonogi, Ryota Munetomo, Hiroya Oki, Takuya Yoshida, Yuko Kumeda, Shigeaki Matsuda, Toshio Kodama, Tadayasu Ohkubo, Tetsuya Iida, Shota Nakamura
Binary enterotoxin of Clostridium perfringens (BEC), consisting of the components BECa and BECb, was recently identified as a novel enterotoxin produced by C. perfringens that causes acute gastroenteritis in humans. Although the detailed mechanism of cell intoxication by BEC remains to be defined, BECa shows both NAD(+)-glycohydrolase and actin ADP-ribosyltransferase activities in the presence of NAD(+). In this study, we determined the first crystal structure of BECa in its apo-state and in complex with NADH...
October 14, 2016: Biochemical and Biophysical Research Communications
Smita Gupta, Sunita Yadav, Venkatesan Suryanarayanan, Sanjeev K Singh, Jitendra K Saxena
Guanylate kinase is one of the key enzymes in nucleotide biosynthesis. The study highlights the structural and functional properties of Brugia malayi Guanylate kinase (BmGK) in the presence of chemical denaturants. An inactive, partially unfolded, dimeric intermediate was observed at 1-2M urea while GdnCl unfolding showed monomer molten globule like intermediate at 0.8-1.0M. The results also illustrate the protective role of substrates in maintaining the integrity of the enzyme. The thermo stability of protein was found to be significantly enhanced in the presence of the substrates...
October 14, 2016: International Journal of Biological Macromolecules
Patrick Mucka, Nicholas Levonyak, Elena Geretti, Bernadette M M Zwaans, Xiaoran Li, Irit Adini, Michael Klagsbrun, Rosalyn M Adam, Diane R Bielenberg
The vasculature influences the progression and resolution of tissue inflammation. Capillaries express vascular endothelial growth factor (VEGF) receptors, including neuropilins (NRPs), which regulate interstitial fluid flow. NRP2, a receptor of VEGFA and semaphorin (SEMA) 3F ligands, is expressed in the vascular and lymphatic endothelia. Previous studies have demonstrated that blocking VEGF receptor 2 attenuates VEGFA-induced vascular permeability. The inhibition of NRP2 was hypothesized to decrease vascular permeability as well...
October 12, 2016: American Journal of Pathology
Simon Schimmack, Ben Lawrence, Barton Kenney, Hubertus Schmitz-Winnenthal, Irvin M Modlin, Mark Kidd
BACKGROUND: Small intestinal neuroendocrine neoplasm (SI-NEN) proliferation is quantified by Ki67 measurements which capture G1-G2M phases of the cell cycle. G0 and early G1 phases, typical of slow-growing cells, can be detected by minichromosome maintenance protein (MCM) expression. We hypothesized that these replication licensing markers may provide clinically relevant information to augment Ki67 in low-grade neuroendocrine neoplasia. METHODS: Immunohistochemical staining (IHC), Western blot analysis, quantitative polymerase chain reaction, and copy number variations of MCM2, MCM3, and Ki67 were undertaken in SI-NENs (n = 22)...
October 2016: Translational Oncology
Elsa Perrody, Laurence Abrami, Michal Feldman, Beatrice Kunz, Sylvie Urbé, Gisou van der Goot
Many membrane proteins fold inefficiently and require the help of enzymes and chaperones. Here we reveal a novel folding assistance system that operates on membrane proteins from the cytosolic side of the endoplasmic reticulum (ER). We show that folding of the Wnt signaling coreceptor LRP6 is promoted by ubiquitination of a specific lysine, retaining it in the ER while avoiding degradation. Subsequent ER exit requires removal of ubiquitin from this lysine by the deubiquitinating enzyme USP19. This ubiquitination-deubiquitination is conceptually reminiscent of the glucosylation-deglucosylation occurring in the ER lumen during the calnexin/calreticulin folding cycle...
October 18, 2016: ELife
Hye Yeon Koh, Hyun Park, Jun Hyuck Lee, Se Jong Han, Young Chang Sohn, Sung Gu Lee
Psychrobacter sp. PAMC 21119, isolated from Antarctic permafrost soil, grows and proliferates at subzero temperatures. However, its major mechanism of cold adaptation regulation remains poorly understood. We investigated the transcriptomic and proteomic responses of this species to cold temperatures by comparing profiles at -5°C and 20°C to understand how extreme microorganisms survive under subzero conditions. We found a total of 2,906 transcripts and 584 differentially expressed genes (≥ 2 fold, p <0...
October 17, 2016: Environmental Microbiology
Joseph R Sachleben, Aashish N Adhikari, Grzegorz Gawlak, Robert J Hoey, Gaohua Liu, Andrzej Joachimiak, Gaetano T Montelione, Tobin R Sosnick, Shohei Koide
We determined the NMR structure of a highly aromatic (13%) protein of unknown function, Aq1974 from Aquifex aeolicus. The unusual sequence of this protein has a tryptophan content 5 times the normal (six tryptophan residues of 114 or 5.2% while the average tryptophan content is 1.0%) with the tryptophans occurring in a WXW motif. It has no detectable sequence homology with known protein structures. Although its NMR spectrum suggested that the protein was rich in β-sheet, upon resonance assignment and solution structure determination, the protein was found to be primarily α-helical with a small two-stranded β-sheet with a novel fold that we have termed an Aromatic Claw...
October 17, 2016: Protein Science: a Publication of the Protein Society
Mikko Laitaoja, Sari Isoniemi, Jarkko Valjakka, Istvan M Mándity, Janne Jänis
Small zinc finger (ZnF) motifs are promising molecular scaffolds for protein design owing to their structural robustness and versatility. Moreover, their characterization provides important insights into protein folding in general. ZnF motifs usually possess an exceptional specificity and high affinity towards Zn(II) ion to drive folding. While the Zn(II) ion is canonically coordinated by two cysteine and two histidine residues, many other coordination spheres also exist in small ZnFs, all having four amino acid ligands...
October 17, 2016: Protein Science: a Publication of the Protein Society
Aymeric Goyer
Thiamin is essential for human health. While plants are the ultimate source of thiamin in most human diets, staple foods like white rice have low thiamin content. Therefore, populations whose diets are mainly based on low-thiamin staple crops suffer from thiamin deficiency. Biofortification of rice grain by engineering the thiamin biosynthesis pathway has recently been attempted, with up to 5-fold increase in thiamin content in unpolished seeds. However, polished seeds that retain only the starchy endosperm had similar thiamin content than that of non-engineered plants...
October 14, 2016: Current Opinion in Biotechnology
Kristen T Crowell, David I Soybel, Charles H Lang
Muscle deconditioning is commonly observed in patients surviving sepsis. Little is known regarding the molecular mechanisms regulating muscle protein homeostasis during the recovery or convalescence phase. We adapted a sepsis-recovery mouse model that uses cecal ligation and puncture (CLP), followed 24 h later by cecal resection and antibiotic treatment, to identify putative cellular pathways regulating protein synthesis and breakdown in skeletal muscle. Ten days after CLP, body weight and food consumption did not differ between control and sepsis-recovery mice, but gastrocnemius weight was reduced...
October 5, 2016: Shock
Sedar Karakurt
Expression of a drug and xenobiotic metabolizing enzymes, cytochrome P450s (CYPs), and antioxidant enzymes can be modulated by various factors. The flavonoid rutin was investigated for its anti-carcinogen and protective effects as well as modulatory action on CYPs and phase II enzymes in human hepatocellular carcinoma cells. Rutin inhibited proliferation of HEPG2 cells in a dose-dependent manner with the IC50 value of 52.7 μmol L-1 and invasion of HEPG2 cells (21.6 %, p = 0.0018) and colony formation of those invaded cells (57...
December 1, 2016: Acta Pharmaceutica
G N Nguyen, L A George, J I Siner, R J Davidson, C B Zander, X L Zheng, V R Arruda, R M Camire, D E Sabatino
BACKGROUND: The major challenge for developing gene-based therapies for hemophilia A is that human factor VIII (hFVIII) has intrinsic properties that result in inefficient biosynthesis. During intracellular processing, hFVIII is predominantly cleaved at a Paired basic Amino acid Cleaving Enzyme (PACE) or furin cleavage site to yield a heterodimer that is the major form of secreted protein. Previous studies with B-domain deleted (BDD) canine FVIII and hFVIII-R1645H, both differing from hFVIII by a single amino acid at this site, suggested that these proteins are secreted mainly in a single polypeptide chain (SC) form and exhibit enhanced function...
October 17, 2016: Journal of Thrombosis and Haemostasis: JTH
Xiaojuan Huang, Jung-Ho Shin, Azul Pinochet-Barros, Tina T Su, John D Helmann
The Bacillus subtilis MntR metalloregulatory protein senses manganese, an essential element required for central metabolism, oxidative stress resistance and replication. An mntR null mutant is highly sensitive to Mn(II) intoxication, which is attributed in part to the constitutive expression of two importers: the proton-dependent NRAMP family transporter MntH and the ABC transporter MntABCD. Here, we show that an mntR null mutant is still sensitive to Mn(II) intoxication even if both of the import systems are absent...
October 17, 2016: Molecular Microbiology
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