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Amino acid

Vasanthanathan Poongavanam, Jacob Kongsted
The high rate of drug resistance as well as the complex biochemical process of the parasite reproduction cycle makes development of new drugs for malaria a very important but challenging task. Falcipain 2 (FL2) and Falcipain 3 (FL3) are the major cysteine protease enzymes that play a central role in providing essential amino acids for the parasite's protein biosynthesis through the hemoglobin hydrolysis process. Selective inhibition of these enzymes is considered as a promising chemotherapeutic target. In the present investigation, the highly efficient linear interaction energy (LIE) method has been parameterized for binding affinity predictions and assessed with a set of 244 compounds for FL2 and FL3 inhibition...
June 26, 2016: Journal of Molecular Graphics & Modelling
Mahejibin Khan, Amit Kumar
The understanding of the 3-dimensional enzyme structure is important for the point of protein engineering and applications. Computer-based molecular modelling is a vital tool for theoretical predication of enzyme activities and finding their substrates and inhibitors. SMlipA lipase was cloned from forest soil metagenome and characterized as broad spectrum enzyme with high stability in various organic solvents. In the present study, to understand the mechanism of SMlipA lipase and to identify the key residues involved in enzyme-substrate interaction, three dimensional-computational model of SMlipA has been generated and validated for stereo-chemical and amino-acid environment quality using appropriate programs, and further validation of the active-site architecture was achieved by performing docking studies with different ligand...
October 14, 2016: Journal of Molecular Graphics & Modelling
Andrei Tsentsevitsky, Leniz Nurullin, Evgeny Nikolsky, Artem Malomouzh
There is some evidence that glutamate (Glu) acts as a signaling molecule at vertebrate neuromuscular junctions where acetylcholine (ACh) serves as a neurotransmitter. In this study, performed on the cutaneous pectoris muscle of the frog Rana ridibunda, Glu receptor mechanisms that modulate ACh release processes were analyzed. Electrophysiological experiments showed that Glu reduces both spontaneous and evoked quantal secretion of ACh and synchronizes its release in response to electrical stimulation. Quisqualate, an agonist of ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptors and metabotropic Group I mGlu receptors, also exerted Glu-like inhibitory effects on the secretion of ACh but had no effect on the kinetics of quantal release...
October 22, 2016: Journal of Neuroscience Research
Verónica María Corrales-Carvajal, Aldo A Faisal, Carlos Ribeiro
Internal states can profoundly alter the behavior of animals. A quantitative understanding of the behavioral changes upon metabolic challenges is key to a mechanistic dissection of how animals maintain nutritional homeostasis. We used an automated video tracking setup to characterize how amino acid and reproductive states interact to shape exploitation and exploration decisions taken by adult Drosophila melanogaster. We find that these two states have specific effects on the decisions to stop at and leave proteinaceous food patches...
October 22, 2016: ELife
Alexander Jarasch, Arne Skerra
The analysis and comparison of large numbers of immunoglobulin (Ig) sequences that arise during an antibody selection campaign can be time-consuming and tedious. Typically, the identification and annotation of framework as well as complementarity-determining regions (CDRs) is based on multiple sequence alignments using standardized numbering schemes, which allow identification of equivalent residues among different family members but often necessitate expert knowledge and manual intervention. Moreover, due to the enormous length variability of some CDRs the benefit of conventional Ig numbering schemes is limited and the calculation of correct sequence alignments can become challenging...
October 22, 2016: Proteins
Hasup Lee, Minkyung Baek, Gyu Rie Lee, Sangwoo Park, Chaok Seok
Many proteins function as homo- or hetero-oligomers; therefore, attempts to understand and regulate protein functions require knowledge of protein oligomer structures. The number of available experimental protein structures is increasing, and oligomer structures can be predicted using the experimental structures of related proteins as templates. However, template-based models may have errors due to sequence differences between the target and template proteins, which can lead to functional differences. Such structural differences may be predicted by loop modeling of local regions or refinement of the overall structure...
October 22, 2016: Proteins
M I Boguś, E Włóka, A Wrońska, A Kaczmarek, M Kazek, K Zalewska, M Ligęza-Żuber, M Gołębiowski
Entomopathogenic fungi infect insects via penetration through the cuticle, which varies remarkably in chemical composition across species and life stages. Fungal infection involves the production of enzymes that hydrolyse cuticular proteins, chitin and lipids. Host specificity is associated with fungus-cuticle interactions related to substrate utilization and resistance to host-specific inhibitors. The soil fungus Conidiobolus coronatus (Constantin) (Entomophthorales: Ancylistaceae) shows virulence against susceptible species...
October 22, 2016: Medical and Veterinary Entomology
Bartosz Roszniowski, Agnieszka Latka, Barbara Maciejewska, Dieter Vandenheuvel, Tomasz Olszak, Yves Briers, Giles S Holt, Miguel A Valvano, Rob Lavigne, Darren L Smith, Zuzanna Drulis-Kawa
Burkholderia phage AP3 (vB_BceM_AP3) is a temperate virus of the Myoviridae and the Peduovirinae subfamily (P2likevirus genus). This phage specifically infects multidrug-resistant clinical Burkholderia cenocepacia lineage IIIA strains commonly isolated from cystic fibrosis patients. AP3 exhibits high pairwise nucleotide identity (61.7 %) to Burkholderia phage KS5, specific to the same B. cenocepacia host, and has 46.7-49.5 % identity to phages infecting other species of Burkholderia. The lysis cassette of these related phages has a similar organization (putative antiholin, putative holin, endolysin, and spanins) and shows 29-98 % homology between specific lysis genes, in contrast to Enterobacteria phage P2, the hallmark phage of this genus...
October 21, 2016: Applied Microbiology and Biotechnology
Raj Kumar Sharma, Kumudesh Mishra, Alvina Farooqui, Anu Behari, Vinay Kumar Kapoor, Neeraj Sinha
OBJECTIVE AND DESIGN: We present in this article (1)H nuclear magnetic resonance (NMR)-based metabolic approach to screen the serum metabolic alterations in human gallbladder inflammation with chronic cholecystitis (CC). MATERIAL/METHODS: Total of 71 human serum samples was divided into two groups, (n = 41, CC) and (n = 30 control). (1)H NMR metabolic profiling was carried out for investigation of metabolic alterations. Multivariate statistical analysis was applied for pattern recognition and identification of metabolites playing crucial role in gallbladder inflammation...
October 21, 2016: Inflammation Research: Official Journal of the European Histamine Research Society ... [et Al.]
Lana Shabala, Jingyi Zhang, Igor I Pottosin, Jayakumar Bose, Min Zhu, Anja Thoe Fuglsang, Ana Velarde-Buendia, Amandine Massart, Camilla B Hill, Ute Roessner, Antony Bacic, Honghong Wu, Elisa Azzarello, Camilla Pandolfi, Meixue Zhou, Charlotte Poschenrieder, Stefano Mancuso, Sergey Shabala
While the importance of cell-type specificity in plant adaptive responses is widely accepted, only a limited number of studies have addressed this issue at the functional level. We have combined electrophysiological, imaging, and biochemical techniques to reveal physiological mechanisms conferring higher sensitivity of apical root cells to salinity in barley. We show that salinity application to the root apex arrests root growth in a highly tissue- and treatment-specific manner. Although salinity-induced transient net Na+ uptake was about 4-fold higher in the root apex compared with the mature zone, mature root cells accumulated more cytosolic and vacuolar Na+ suggesting that higher sensitivity of apical cells to salt is not related to either enhanced Na+ exclusion or sequestration inside the root...
October 21, 2016: Plant Physiology
Akhi Akhter, Emanuel Rosonina
The Saccharomyces cerevisiae transcription factor Gcn4 is expressed during amino acid starvation and its abundance is controlled by ubiquitin-mediated proteolysis. Cdk8, a kinase component of the RNA polymerase II Mediator complex, phosphorylates Gcn4 which triggers its ubiquitination/proteolysis and is thought to link Gcn4 degradation with transcription of target genes. In addition to phosphorylation and ubiquitination, we previously showed that Gcn4 becomes sumoylated in a DNA-binding dependent manner, while a non-sumoylatable form of Gcn4 showed increased chromatin occupancy, but only if Cdk8 was present...
October 21, 2016: Genetics
Chanakan Tongsook, Johannes Niederhauser, Elena Kronegger, Grit Straganz, Peter Macheroux
The degradation of histamine catalyzed by the SAM-dependent histamine N-methyltransferase (HNMT) is critically important for the maintenance of neurological processes. Recently, two mutations in the encoding human gene were reported to give rise to dysfunctional protein variants (G60D and L208P) leading to intellectual disability. In the present study, we have expressed eight L208 variants with either apolar (L208F and L208V), polar (L208N and L208T) or charged (L208D, L208H, L208K and L208R) amino acids to define the impact of side chain variations on protein structure and function...
October 18, 2016: Biochimica et Biophysica Acta
Francisca Sanchez-Jiménez, Almudena Pino-Ángeles, Rocio Rodríguez-López, María Morales, José Luis Urdiales
Human histidine decarboxylase (HDC) and dopa decarboxilase (DDC) are highly homologous enzymes responsible for the synthesis of biogenic amines (BA) like histamine, and serotonin and dopamine, respectively. The enzymes share many structural and functional analogies, while their product metabolisms also follow similar patterns that are confluent in some metabolic steps. They are involved in common physiological functions, such as neurotransmission, gastrointestinal track function, immunity, cell growth and cell differentiation...
October 18, 2016: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
Kattina Zavala, Michael W Vandewege, Federico G Hoffmann, Juan C Opazo
The study of the evolutionary history of genes related to human disease lies at the interface of evolution and medicine. These studies provide the evolutionary context on which medical researchers should work, and are also useful in providing information to suggest further genetic experiments, especially in model species where genetic manipulations can be made. Here we studied the evolution of the β-adrenoreceptor gene family in vertebrates with the aim of adding an evolutionary framework to the already abundant physiological information...
October 18, 2016: General and Comparative Endocrinology
Ji Ye Lee, Na Hyun Park, Wonwoong Lee, Eun Hye Kim, Young Ho Jin, Eun Kyung Seo, Jongki Hong
A comprehensive profiling method was established for the determination of various chemicals in Pinellia (P.) ternata and pedatisecta species. The profiling method comprises a fast ultrasonic extraction with various solvents, followed by GC-MS and LC-APCI-MS analysis. A total of 73 polar components as trimethylsilyl (TMS) derivatives were detected in methanol extract by GC-MS. The main components of the P. species were profiled as several kinds of fatty acids, amino acids, nucleic acids, carbohydrates, and phenolic compounds...
October 13, 2016: Journal of Chromatography. A
Natta Wiriyakun, Duangjai Nacapricha, Rattikan Chantiwas
This work presents a simple hot embossing method with a shrinking procedure to produce cross-shape microchannels on poly(methyl methacrylate) (PMMA) substrate for the fabrication of an electrophoresis chip. The proposed method employed a simple two-step hot embossing technique, carried out consecutively on the same piece of substrate to make the crossing channels. Studies of embossing conditions, i.e. temperature, pressure and time, were carried out to investigate their effects on the dimension of the microchannels...
December 1, 2016: Talanta
Noemí León-Roque, Mohamed Abderrahim, Luis Nuñez-Alejos, Silvia M Arribas, Luis Condezo-Hoyos
Several procedures are currently used to assess fermentation index (FI) of cocoa beans (Theobroma cacao L.) for quality control. However, all of them present several drawbacks. The aim of the present work was to develop and validate a simple image based quantitative procedure, using color measurement and artificial neural network (ANNs). ANN models based on color measurements were tested to predict fermentation index (FI) of fermented cocoa beans. The RGB values were measured from surface and center region of fermented beans in images obtained by camera and desktop scanner...
December 1, 2016: Talanta
Heikki Aisala, Jari Sinkkonen, Marika Kalpio, Mari Sandell, Hervé This, Anu Hopia
A direct quantitative proton nuclear magnetic resonance spectroscopy method was developed for the measurement of saccharides, organic acids and amino acids in potato (Solanum tuberosum L.) tuber filaments, a complex gel-like food matrix. The method requires minimal sample preparation. It is thus a faster alternative compared to liquid sample matrices, as well as an extension to methods analyzing only selected metabolites in the sample. The samples in this study were either raw or steamed potato strips that were either measured as D2O extracts or directly without extraction or derivatization steps (in situ technique)...
December 1, 2016: Talanta
Jiankun Cao, Hongyuan Yan, Shigang Shen, Ligai Bai, Haiyan Liu, Fengxia Qiao
New hydrophilic molecularly imprinted melamine-urea-formaldehyde monolithic resin (MIMR) is synthesized using dopamine hydrochloride as a dummy template via in-situ polymerization directly within pipette tips and it presents special molecular recognition to plant growth regulators in aqueous matrices. Hydrophilic groups (such as hydroxyl groups, imino groups, and amino groups) can be introduced into MIMR by melamine- urea-formaldehyde resin, which make MIMR materials compatible with aqueous media and show their specific molecular recognition in aqueous sample solutions...
November 2, 2016: Analytica Chimica Acta
Lukasz P Kozlowski
BACKGROUND: Accurate estimation of the isoelectric point (pI) based on the amino acid sequence is useful for many analytical biochemistry and proteomics techniques such as 2-D polyacrylamide gel electrophoresis, or capillary isoelectric focusing used in combination with high-throughput mass spectrometry. Additionally, pI estimation can be helpful during protein crystallization trials. RESULTS: Here, I present the Isoelectric Point Calculator (IPC), a web service and a standalone program for the accurate estimation of protein and peptide pI using different sets of dissociation constant (pKa) values, including two new computationally optimized pKa sets...
October 21, 2016: Biology Direct
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