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Results 301 - 350 of 1409
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Ambrogelly Alexandre - - 2007
At the time of its discovery four decades ago, the genetic code was viewed as the result of a "frozen accident." Our current knowledge of the translation process and of the detailed structure of its components highlights the roles of RNA structure (in mRNA and tRNA), RNA modification (in tRNA), ...
Miklán Zsanett - - 2007
Data reported in this article describe the synthesis of Arg-rich oligopeptide conjugates of ferrocenecarboxylic acid on solid support with two different strategies and for the first time, the successful preparation of peptide conjugates of ferrocenylacrylic acid in solution. The antitumor effect of conjugates was analyzed by MTT assay in vitro. ...
Zhang Jian - - 2007
The effects of neighboring residues and formulation variables on tyrosine oxidation were investigated in model dipeptides (glysyl tyrosine, N-acetyl tyrosine, glutamyl tyrosine, and tyrosyl arginine) and tripeptide (lysyl tyrosyl lysine). The tyrosyl peptides were oxidized by light under alkaline conditions by a zero-order reaction. The rate of the photoreaction was ...
SzymaƄski Maciej - - 2007
The genetic code discovered 40 years ago, consists of 64 triplets (codons) of nucleotides. The genetic code is almost universal. The same codons are assigned to the same amino acids and to the same START and STOP signals in the vast majority of genes in animals, plants, and microorganisms. Each ...
Liu Xiangyang - - 2007
Lipopeptides are amphiphilic compounds which contain both hydrophobic fatty acid moieties and amphiphilic peptide moieties. From the cell-free broth of Bacillus subtilis HSO121, eight cyclic lipopeptides were isolated by reversed-phase high performance liquid chromatography (RP-HPLC). The peptide part of each lipopeptide was elucidated according to electrospray ionization quadruple-time-of-flight mass spectrometry ...
Herring Stephanie - - 2007
Pyrrolysine (Pyl), the 22nd co-translationally inserted amino acid, is incorporated in response to a UAG amber stop codon. Pyrrolysyl-tRNA synthetase (PylRS) attaches Pyl to its cognate tRNA, the special amber suppressor tRNA(Pyl). The genes for tRNA(Pyl) (pylT) and PylRS (pylS) are found in all members of the archaeal family Methanosarcinaceae, ...
Higgs Paul G - - 2007
Many different selective effects on DNA and proteins influence the frequency of codons and amino acids in coding sequences. Selection is often stronger on highly expressed genes. Hence, by comparing high- and low-expression genes it is possible to distinguish the factors that are selected by evolution. It has been proposed ...
Cropp T Ashton TA Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, USA. - - 2007
The genetic code of living organisms has been expanded to allow the site-specific incorporation of unnatural amino acids into proteins in response to the amber stop codon UAG. Numerous amino acids have been incorporated including photo-crosslinkers, chemical handles, heavy atoms and post-translational modifications, and this has created new methods for ...
Balsved Dorte - - 2007
Tyrosine O-sulfation is a posttranslational modification of secretory and membrane proteins transported through the Golgi apparatus, which is widespread among higher eukaryotes. O-Sulfated tyrosines are not immediately identified during sequencing of peptides and proteins, because the sulfate ester is acid labile and rapidly hydrolyses to tyrosine in strong acidic solutions. ...
Deigin V I - - 2007
The influence of Glu-Trp (EW) synthetic dipeptide isomers on hemopoietic progenitor cells and certain immune response reactions is determined by their optical and chemical properties. Thus, the all L-amino acid containing dipeptides L-Glu-L-Trp and L-gammaGlu-L-Trp have no effect on proliferation of committed and pluripotent CFU-S in intact bone marrow. The ...
Sforza Stefano - - 2006
The effect of the dry-curing processing time on the release of oligopeptides and amino acids was evaluated with 158 Parma hams subdivided into three groups: (1) traditional processing (450 days); (2) extended processing (570 days); and (3) extended aging (690 days). Most of the oligopeptides and free amino acids detected ...
Taki Masumi - - 2006
Spodoptera frugiperda 21 (Sf21) insect cell-free protein synthesizing system was expanded to include nonnatural amino acids. Orthogonal tRNAs that work as carriers of nonnatural amino acids in the insect system were explored. Four-base codons for assigning the positions of nonnatural amino acids were also selected. Mutated streptavidin mRNAs that contained ...
Badadani Mallikarjun - - 2007
A method for urinary peptide(s) and protein hydrolysis, involving autoclaving at 15psi (121 degrees C) for 60min, is described. Using three candidate proteins (bovine serum albumin, casein and gelatin) and urine specimens, the effect of autoclaving with respect to the optimum time required for hydrolysis under both acidic (6N HCl) ...
Penner Marlin - - 2007
Beta-peptidic-D-gluco-, D-galacto-, and L-fuco-configured glycosyl amino acids can be prepared from the corresponding 2-deoxy-oct-3-ulopyranosonic acids via a one-pot intramolecular Ritter reaction. Initially, a ketopyranoside-based acid condenses under Lewis acid promoted conditions with nitriles (PhCN, MeCN) and a partially protected diamino ester (Boc-DAB-O-t-Bu, Boc-Orn-O-t-Bu) to form a beta-peptidic glycosyl amino t-butylesters. ...
Jurado Angela - - 2007
The evolution of free amino acids and amino acid-derived volatile compounds during the ripening of Iberian ham from pigs reared in a Montanera system (outdoor-based, with acorn and pasture available) and a Pienso system (indoor-based, with a high oleic acid concentrate) was studied. Ripening time influenced significantly all the free ...
Suhs Thomas - - 2006
We report the synthesis of guanidino amino acids (GuAA), which are structurally related to Arg and resemble a dipeptide consisting of alpha- and gamma-amino acid with a guanidinium group in the main chain. The compounds are available with different protecting groups in gram amounts and are intended as synthetic building ...
Porat Y - - 2006
The 15-mer dermaseptin S4 derivative S4(1-15) was recently shown to exhibit potent activity against oral pathogens associated with caries and periodontitis. Here, we investigated possible modes for improving the peptide's properties through systematic replacement of an N-terminal amino acid(s) with various fatty acids that modulate the peptide's hydrophobicity and/or charge. ...
David Ralf - - 2007
The three-dimensional structure of human interleukin-8 (hIL-8) was determined by the use of NMR and X-ray methodology. At high concentrations interleukin-8 and many other chemokines form a non-covalent homodimer. Several studies have been performed to investigate the relevance of the dimer on receptor activation and led to contradictory results. In ...
Nagaike Fumihiro - - 2006
A peptide carrying a mercaptomethylated proline derivative at the C-terminus was prepared by solid-phase peptide synthesis (SPPS) and converted to the thioester of 3-mercaptopropionic acid (MPA) by aqueous MPA under microwave irradiation conditions. This post-SPPS thioesterification reaction was successfully applied to the synthesis of a glycopeptide thioester composed of 25 ...
Torabi Noorossadat - - 2007
The fidelity of the translation machinery largely depends on the accuracy by which the tRNAs within the living cells are charged. Aminoacyl-tRNA synthetases (aaRSs) attach amino acids to their cognate tRNAs ensuring the fidelity of translation in coding sequences. Based on the sequence analysis and catalytic domain structure, these enzymes ...
Higaki-Sato Noriko - - 2006
In order to determine pyroglutamic acid levels in plasma, we developed a method based on precolumn derivatization of the carboxyl group of pyroglutamic acid with 2-nitrophenylhydrazine. Eight-week-old male SD strain rats were administered 200 mg of an acidic peptide fraction obtained from a commercial wheat gluten hydrolysate containing 0.63 mmol/g ...
Ebran Jean-Philippe - - 2006
In this perspective, an overview of our experiences on the application of samarium diiodide in organic synthesis for the preparation of amino acid and peptide analogues is presented. Three different carbon-carbon bond forming reactions are discussed, including side chain introductions, gamma-amino acid synthesis and acyl-like radical additions for the construction ...
Jessing Mikkel - - 2006
Solid-phase synthesis is of tremendous importance for small-molecule and biopolymer synthesis. Linkers (handles) that release amide-containing products after completion of solid-phase synthesis are widely used. Here we present a new class of highly acid-labile backbone amide linkers (BAL handles) based on 3,4-ethylenedioxythiophene (EDOT), which we have termed T-BAL. These thiophene ...
García-Aparicio Carlos - - 2006
Here we describe a novel type of enzyme-based prodrug approach in which a dipeptide moiety is linked to a nonpeptidic therapeutic drug through an amide bond which is specifically cleaved by the dipeptidyl-peptidase IV (DPP IV/CD26) enzyme activity present in plasma and on the surface of certain cells. DPP IV ...
Carrasco Michael R - - 2006
Peptides containing N-alkylaminooxy amino acids were chemoselectively alkylated with allylic, benzylic, and alpha-carbonyl bromides, N-ethylmaleimide, and hexyl acrylate in mildly acidic aqueous/organic solutions. Alkylation at the aminooxy nitrogen proceeds in good yields with excellent to complete chemoselectivity in the presence of all common amino acids except cysteine. This reaction complements ...
Nagai Yusuke - - 2006
Biological hydrogels consisting of self-assembling peptide nanofibers are potentially excellent materials for various controlled molecular release applications. The individual nanofiber consists of ionic self-complementary peptides with 16 amino acids (RADA16, Ac-RADARADARADARADA-CONH(2)) that are characterized by a stable beta-sheet structure and undergo self-assembly into hydrogels containing approximately 99.5% w/v water. We ...
Solsona Imma Andorra - - 2006
A new approach to the design of selective release interfaces is assessed in which a hydrophobic component is functionalised with a receptor reactive toward reduced thiol peptides-principally glutathione. The assembly has been characterised using electrochemical techniques and its ability to form a coherent, water insoluble coating is demonstrated. The subsequent ...
Tran Tran T - - 2006
Drug design can benefit from the use of non-coded amino acids, such as alpha-amino isobutyric acids (Aib) or sarcosine (N-methyl-glycine). Non-coded amino acids can confer resistance to enzymatic degradation and increase the conformational stability of the peptides. We have simulated the conformational effects of combining N-methylation, bulky groups on the ...
Danger Grégoire - - 2006
Similar to many ureas, N-carbamoylamino acids were shown to be hydrolyzed in aqueous solution through elimination mechanisms at close to neutral pH, the nucleophilic attack of water being a minor process. Two competing elimination mechanisms can take place involving either cyanate or isocyanate transient intermediates. Peptide formation was observed and ...
Giel-Pietraszuk Malgorzata - - 2006
We show a simple and reliable method of tRNA aminoacylation with natural, as well as non-natural, amino acids at high pressure. Such specific and noncognate tRNAs can be used as valuable substrates for protein engineering. Aminoacylation yield at high pressure depends on the chemical nature of the amino acid used ...
Imamura Takeyoshi - - 2006
The free energies of transfer for indole and tryptophan derivatives and pentapeptides having single tryptophan residues from aqueous to sodium dodecyl sulfate (SDS) micellar phases have been systematically studied using the conventional method of ultraviolet absorption spectrophotometry. The free energies for the position isomers of methyl indoles varied depending on ...
Kocsis László - - 2006
Different characteristics of cleavage kinetics of resin-bound amino alcohols and their peptide derivatives were observed in acid containing protic and aprotic solvent mixtures. The hydrolysis reactions are hindered by steric crowding around the cleaving C--O bond and accelerated by the special solvation effect of CF(3)CH(2)OH on the peptide chain as ...
Vermeulen Nicoline - - 2006
Bread spoilage is mainly due to the growth of filamentous fungi, and metabolites produced during sourdough fermentation by lactobacilli can inhibit fungal growth. One of these metabolites is phenyllactic acid (PLA), which is a catabolite from phenylalanine. In this work, the influence of peptide supply and cosubstrates was determined on ...
Lobanov Alexey V - - 2006
The universal genetic code includes 20 common amino acids. In addition, selenocysteine (Sec) and pyrrolysine (Pyl), known as the twenty first and twenty second amino acids, are encoded by UGA and UAG, respectively, which are the codons that usually function as stop signals. The discovery of Sec and Pyl suggested ...
Krause C - - 2006
"Proteomics" and "peptidomics" are used as technical terms to define the analysis and study of all proteins and peptides expressed in an organism or tissue. In analogy we propose the name peptaibiomics for the analysis of a group of fungal peptide antibiotics (peptaibiotics) containing the characteristic amino acid Aib (alpha-aminoisobutyric ...
Matsuo Ei-Ichi - - 2006
The 2-nitrobenzenesulfenyl (NBS) method, which is useful for quantitative proteome analysis, is based on stable isotope labeling of tryptophan residues with NBS chloride ((12)C(6)-NBSCl or (13)C(6)-NBSCl). We found that 3-hydroxy-4-nitrobenzoic acid (3H4NBA) is a more suitable matrix than 2,5-dihydroxybenzoic acid (DHB) for detecting NBS-labeled peptides by MALDI-quadrupole IT (QIT)-TOF MS ...
Balaji Baghavathy S - - 2006
An efficient and highly versatile method for the synthesis of amino acid-modified peptide nucleic acid (PNA) monomers is described. By using solid-phase Fmoc techniques, such monomers can be assembled readily in a stepwise manner and obtained in high yield with minimal purification. Protected neutral hydrophilic, acidic, and basic amino acids ...
Edosada Conrad Yap - - 2006
Fibroblast activation protein (FAP) is a serine protease of undefined endopeptidase specificity implicated in tumorigenesis. To characterize FAP's P(4)-P(2)(') specificity, we synthesized intramolecularly quenched fluorescent substrate sets based on the FAP cleavage site in alpha(2)-antiplasmin (TSGP-NQ). FAP required substrates with Pro at P(1) and Gly or d-amino acids at P(2) ...
Torres Allan M - - 2006
The presence of d-amino-acid-containing polypeptides, defensin-like peptide (DLP)-2 and Ornithorhyncus venom C-type natriuretic peptide (OvCNP)b, in platypus venom suggested the existence of a mammalian d-amino-acid-residue isomerase(s) responsible for the modification of the all-l-amino acid precursors. We show here that this enzyme(s) is present in the venom gland extract and is ...
Fukuyama Yuko - - 2006
MS/MS is indispensable for the amino acid sequencing of peptides. However, its use is limited for peptides containing disulfide bonds. We have applied the reducing properties of 1,5-diaminonaphthalene (1,5-DAN) as a MALDI matrix to amino acid sequencing and disulfide bond mapping of human urotensin II possessing one disulfide bond, and ...
Pujals Sílvia - - 2006
In recent years, cell-penetrating peptides have proven to be an efficient intracellular delivery system. The mechanism for CPP internalisation, which first involves interaction with the extracellular matrix, is followed in most cases by endocytosis and finally, depending on the type of endocytosis, an intracellular fate is reached. Delivery of cargo ...
Kinkead Becky - - 2006
This study exemplifies the use of three ADHD-relevant methodological innovations. (1) The use of novel, patented, computational peptide design techniques to generate peptides targeting the extra-cellular and para-transmembrane amino acid loops of the putatively ADHD-involved, D(2) dopamine receptor, D(2)DAR; (2) experimental evidence that these peptides in L-amino acid/ortho ordered or ...
Thingholm Tine E - - 2006
The characterization of phosphorylated proteins is a challenging analytical task since many of the proteins targeted for phosphorylation are low in abundance and phosphorylation is typically substoichiometric. Highly efficient enrichment procedures are therefore required. Here we describe a protocol for selective phosphopeptide enrichment using titanium dioxide (TiO2) chromatography. The selectivity ...
Murakami Hiroshi - - 2006
Here we describe a de novo tRNA acylation system consisting of artificial ribozymes. This system, the flexizyme (Fx) system, allows for the preparation of acyl-tRNAs with almost no limitation on the use of a variety of amino/hydroxy acids and tRNAs. To demonstrate its utility, we have carried out protein synthesis ...
Nordström Anders - - 2006
Perfluorinated surfactants are demonstrated to dramatically enhance desorption/ionization on fluorinated silicon (DIOS) mass spectrometry. Perfluorooctanesulfonic acid improved the signal-to-noise ratio of tryptic digests and gave a 3-fold increase in the number of peptides identified. Similar results were also obtained using perfluoroundecanoic acid; yet among the seven different surfactants tested, controls ...
Talaty Erach R - - 2006
The influence of the presence and position of a single beta-alanine, gamma-aminobutyric acid, epsilon-aminocaproic acid or 4-aminomethylbenzoic acid residue on the tendency to form b(n)+ -and y(n)+ -type product ions was determined using a group of protonated tetrapeptides with general sequence XAAG, AXAG and AAXG (where X refers to the ...
Taira Hikaru - - 2006
An amber suppression method has been used for incorporation of nonnatural amino acids into proteins. However, the incorporation efficiency of nonnatural amino acids through an amber codon has been low, which restricts the application of the proteins containing nonnatural amino acids. In this study, we screened a wide variety of ...
Nishikaze Takashi - - 2006
Factors governing the molecular ion yields of amino acids and peptides have been studied using fast atom bombardment (FAB) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in positive-ion mode. The ion yields of protonated amino acids under FAB conditions are dependent on proton affinity (PA), hydrophobicity, and aromaticity of ...
Tholey Andreas - - 2006
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a powerful tool for the analysis and characterization of protein phosphorylation on the peptide level. In this study, the applicability of ionic liquid matrices (ILM) formed by combination of the crystalline MALDI matrix 2,5-dihydroxybenzoic acid (DHB) with pyridine or n-butylamine was tested for ...
Mock Marissa L - - 2006
The unsaturated amino acid 2-amino-3-methyl-4-pentenoic acid (E-Ile) was prepared in the form of its (2S,3S),(2R,3R) and (2S,3R),(2R,3S) stereoisomeric pairs. The translational activities of SS-E-Ile and SR-E-Ile were assessed in an E. coli strain rendered auxotrophic for isoleucine. SS-E-Ile was incorporated into the test protein mouse dihydrofolate reductase (mDHFR) in place ...
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