Search results for " AMINO"
showing 10 items of 789 documents
Maize based diets and possible neurobehavioural after-effects among some populations in the world
1996
Maize is a cereal particularly lacking in tryptophan, which is the precursor of serotonin, an important neurotransmitter. Altough complementary foods may eliminate tryptophan deficiency, serotonin deficiency may often continue to exist because of competition made by other Large Neutral Amino Acids (LNAA) against tryptophan for neuron access, since they use the same carrier to cross the blood-brain barrier. Thus serotonin synthesis depends on two variables: the amount of tryptophan and the trp/LNAA ratio (R). “R” is lowest for common maize, low for beans and, as a rule, for most vegetable foods, higher for meat. So, when maize is the preponderant food in the meal, the “R” value lowers and so…
Cloning of Two Putative Ecdysteroid Receptor Isoforms from Tenebrio Molitor and their Developmental Expression in the Epidermis during Metamorphosis
1997
Using the Drosophila EcR-B1 cDNA as a probe, we have cloned the putative ecdysteroid receptor from the mealworm Tenebrio molitor. We have isolated two cDNAs with different 5' termini that contain a complete open reading frame. These two cDNAs encode two proteins with distinct N-terminal regions corresponding to two isoforms. The coleopteran receptor is obviously related to the ecdysteroid receptor of other insects, but shares only 89% and 61% amino acid identities with the DNA-binding and ligand-binding domains of the Drosophila receptor, respectively. Its expression pattern has been examined in the epidermis during the last larval instar and pupal stage of T. molitor, in correlation with t…
Glial expression of Swiss cheese (SWS), the Drosophila orthologue of neuropathy target esterase (NTE), is required for neuronal ensheathment and func…
2016
ABSTRACT Mutations in Drosophila Swiss cheese (SWS) or its vertebrate orthologue neuropathy target esterase (NTE), respectively, cause progressive neuronal degeneration in Drosophila and mice and a complex syndrome in humans that includes mental retardation, spastic paraplegia and blindness. SWS and NTE are widely expressed in neurons but can also be found in glia; however, their function in glia has, until now, remained unknown. We have used a knockdown approach to specifically address SWS function in glia and to probe for resulting neuronal dysfunctions. This revealed that loss of SWS in pseudocartridge glia causes the formation of multi-layered glial whorls in the lamina cortex, the firs…
Human tRNA(Sec) associates with HeLa membranes, cell lipid liposomes, and synthetic lipid bilayers.
2012
We have shown previously that simple RNA structures bind pure phospholipid liposomes. However, binding of bona fide cellular RNAs under physiological ionic conditions is shown here for the first time. Human tRNASec contains a hydrophobic anticodon-loop modification: N6-isopentenyladenosine (i6A) adjacent to its anticodon. Using a highly specific double-probe hybridization assay, we show mature human tRNASec specifically retained in HeLa intermediate-density membranes. Further, isolated human tRNASec rebinds to liposomes from isolated HeLa membrane lipids, to a much greater extent than an unmodified tRNASec transcript. To better define this affinity, experiments with pure lipids show that li…
Active Fragments from Pro- and Antiapoptotic BCL-2 Proteins Have Distinct Membrane Behavior Reflecting Their Functional Divergence
2010
International audience; BACKGROUND:The BCL-2 family of proteins includes pro- and antiapoptotic members acting by controlling the permeabilization of mitochondria. Although the association of these proteins with the outer mitochondrial membrane is crucial for their function, little is known about the characteristics of this interaction.METHODOLOGY/PRINCIPAL FINDINGS:Here, we followed a reductionist approach to clarify to what extent membrane-active regions of homologous BCL-2 family proteins contribute to their functional divergence. Using isolated mitochondria as well as model lipid Langmuir monolayers coupled with Brewster Angle Microscopy, we explored systematically and comparatively the…
Structure-Guided, Single-Point Modifications in the Phosphinic Dipeptide Structure Yield Highly Potent and Selective Inhibitors of Neutral Aminopepti…
2014
Seven crystal structures of alanyl aminopeptidase from Neisseria meningitides (the etiological agent of meningitis, NmAPN) complexed with organophosphorus compounds were resolved to determine the optimal inhibitor–enzyme interactions. The enantiomeric phosphonic acid analogs of Leu and hPhe, which correspond to the P1 amino acid residues of well-processed substrates, were used to assess the impact of the absolute configuration and the stereospecific hydrogen bond network formed between the aminophosphonate polar head and the active site residues on the binding affinity. For the hPhe analog, an imperfect stereochemical complementarity could be overcome by incorporating an appropriate P1 side…
Origin of metazoan stem cell system in sponges: first approach to establish the model (Suberites domuncula).
2003
Abstract It is established that Porifera (sponges) represent the earliest phylum which branched off from the common ancestor of all multicellular animals, the Urmetazoa. In the present study, the hypothesis is tested if, during this transition, pluripotent stem cells were formed which are provided—similar to the totipotent cells (archaeocytes/germ cells)—with a self-renewal capacity. As a model system, primmorphs from the sponge Suberites domuncula were used. These 3D-cell aggregates were cultivated in medium (RPMI 1640/seawater) either lacking silicate and ferric iron or in medium which was supplemented with these ‘morphogenetic’ factors. As molecular markers for the potential existence of…
Poly-Xaa Sequences in Proteins - Biological Role and Interactions with Metal Ions: Chemical and Medical Aspects
2016
Background: The understanding of the bioinorganic and coordination chemistry of metalloproteins containing unusual poly-Xaa sequences, in which a single amino acid is repeated consecutively, is crucial for describing their metal binding-structure-function relationship, and therefore also crucial for understanding their medicinal potential. To the best of our knowledge, this is the first systematic review on metal complexes with polyXaa sequences. Methods: We performed a thorough search of high quality peer reviewed literature on poly-Xaa type of sequences in proteins, focusing on their biological importance and on their interactions with metal ions. Results: 228 papers were included in the…
Genes and derived amino acid sequences of S-layer proteins from mesophilic, thermophilic, and extremely thermophilic methanococci
2002
Cells of methanococci are covered by a single layer of protein subunits (S-layer) in hexagonal arrangement, which are directly exposed to the environment and which cannot be stabilized by cellular components. We have isolated S-layer proteins from cells of Methanococcus vannielii ( T(opt.)=37 degrees C), Methanococcus thermolithotrophicus ( T(opt.)=65 degrees C), and Methanococcus jannaschii ( T(opt.)=85 degrees C). The primary structure of the S-layer proteins was determined by sequencing the corresponding genes. According to the predicted amino acid sequence, the molecular masses of the S-layer proteins of the different methanococci are in a small range between 59,064 and 60,547 Da. Compa…
Cloning and functional analysis of cDNA encoding the hamster Bcl-2 protein.
2000
We have cloned cDNA encoding hamster Bcl-2 protein from total RNA of CHO-9 cells by RT-PCR using oligonucleotide primers sharing homology with the sequence of mouse and rat bcl-2. The fragments spanning the total coding region were cloned into pCR4-TOPO and sequenced for verification. The hamster bcl-2 cDNA has a size of 711 nucleotides and encodes a polypeptide of 236 amino acids. Hamster Bcl-2 shares 95.8 and 88.6% similarity with mouse and human Bcl-2, respectively. Northern blot analysis revealed a single 7.5 kb bcl-2 transcript in hamster (CHO-9), mouse (BK4), and rat (H5) cells and a 8.5 kb bcl-2 mRNA in human (HeLa MR) cells. The bcl-2 cDNA (771 bp) was recloned into pcDNA3 and the r…