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Results 401 - 450 of 1409
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Rothman Deborah M - - 2005
We present the chemical and biological synthesis of caged phosphoproteins using the in vitro nonsense codon suppression methodology. Specifically, phosphoamino acid analogues of serine, threonine, and tyrosine with a single photocleavable o-nitrophenylethyl caging group were synthesized as the amino acyl tRNA adducts for insertion into full-length proteins. For this purpose, ...
Yokozeki Kenzo - - 2005
We report herein the development of a novel and efficient enzymatic method for the production of oligopeptides. This newly discovered method is a simple, cost-effective process, using unprotected amino acids as substrates in an aqueous solution and producing peptides in high yield. The target of our initial screen was l-alanyl-L-glutamine, ...
Mori Sumiko - - 2005
Tripeptidases from Lactococcus lactis subsp. lactis (L9PepTR), L. lactis subsp. cremoris (L6PepTR), and L. lactis subsp. hordniae (hTPepTR) were cloned, overexpressed, purified, and characterized. Although these enzymes contained three to seven naturally occurring amino acid differences, both metal-binding and catalytic sites were highly conserved. The k(cat) values of hTPepTR were ...
Swairjo Manal A - - 2005
The genetic code is fixed in aminoacylation reactions catalyzed by aminoacyl-tRNA synthetases. Amino acid discrimination occurs at two sites: one for amino acid activation and aminoacylation and one for editing misactivated amino acids. Although the active site sieves out bulkier amino acids, misactivation occurs with substrates whose side chains are ...
Cho Soung-Hun - - 2005
An antimicrobial peptide was purified from fermented skate skin extract using the solid-phase extraction and separation on HPLC reversed-phase chromatography. Amino acid sequence of the purified peptide (Peak A) having an antimicrobial activity revealed the presence of many cationic residues of the total 28 amino acids. Its molecular mass was ...
Bernatchez Pascal N - - 2005
In endothelia, NO is synthesized by endothelial NO synthase (eNOS), which is negatively regulated by caveolin-1 (Cav-1), the primary coat protein of caveolae. We show that delivery of Cav-1 amino acids 82-101 (Cav) fused to an internalization sequence from Antennapedia (AP) blocks NO release in vitro and inflammation and tumor ...
Rollán G - - 2005
AIMS: To characterize the peptide hydrolase system of Lactobacillus plantarum CRL 759 and CRL 778 and evaluate their proteolytic activity in reducing gliadin-like fractions. METHODS AND RESULTS: The intracellular peptide hydrolase system of Lact. plantarum CRL 759 and CRL 778 involves amino-, di- (DP), tri- (TP) and endopeptidase activities. These ...
Zubin Eugeny M - - 2005
Certain amino acids and short peptides are known to act as enhancers of ribozyme-mediated RNA cleavage at low concentration of magnesium ion. Thus, covalent conjugates of oligonucleotides and some amino acids may have a potential for development as sequence-specific artificial ribonucleases. Here we would like to report an incorporation of ...
Mei Hu - - 2005
In this work, a new set of amino acid descriptors, i.e., VHSE (principal components score Vectors of Hydrophobic, Steric, and Electronic properties), is derived from principal components analysis (PCA) on independent families of 18 hydrophobic properties, 17 steric properties, and 15 electronic properties, respectively, which are included in total 50 ...
Ferdani Riccardo - - 2005
Seven heptapeptide derivatives have been prepared. The peptide structure is (Gly)(3)Xxx(Gly)(3) in which Xxx stands for a variable amino acid. The amino acid variations include azetidine carboxylic acid, pipecolic acid, meta-aminobenzoic acid, proline, and leucine. All seven compounds have a C-terminal benzyl group. In all cases, the heptapeptide's N-terminus was ...
Men Lijie - - 2005
Here we examined the fragmentation, on a quadrupole ion-trap mass spectrometer, of the protonated ions of a group of peptides containing one arginine and two different acidic amino acids, one being aspartic acid (Asp) or glutamic acid (Glu) and the other being cysteine sulfinic acid [C(SO2H)] or cysteine sulfonic acid ...
Maecke Helmut R - - 2005
Radiolabeled peptides are of increasing interest in nuclear oncology. Special emphasis has been given to the development of peptides labeled with positron emitters. Among these, (68)Ga deserves special attention, because it is available from an inhouse generator rendering (68)Ga radiopharmacy independent of an onsite cyclotron. (68)Ga has a half-life of ...
Patel Apoorva - - 2005
Information theoretic analysis of genetic languages indicates that the naturally occurring 20 amino acids and the triplet genetic code arose by duplication of 10 amino acids of class-II and a doublet genetic code having codons NNY and anticodons GNN. Evidence for this scenario is presented based on the properties of ...
Röhrig Christoph H - - 2004
In vitro non-natural amino acid mutagenesis requires aminoacyl-charged suppressor transfer RNAs which read an internal stop codon. For the synthesis of aminoacyl-tRNAs loaded with non-natural amino acids, T4 RNA ligase is used to ligate a chemically synthesised aminoacyl-dinucleotide to a truncated 74mer tRNA(-CA) lacking the two 3' end nucleotides. The ...
Ninomiya Keiko - - 2004
tRNA-specific chemical aminoacylation was achieved with nonnatural amino acids. A nonnatural amino acid was activated as a thioester derivative, and the latter was linked through a spacer to the N-terminal of a 9-mer peptide nucleic acid that is complementary to the 3'-terminal region of yeast phenylalanine tRNA. Efficient aminoacylation was ...
Tian Feng - - 2004
We report a general method to display peptide-containing unnatural amino acids on filamentous M13 phage. Five distinct unnatural amino acids were site-specifically incorporated at the N-terminal of the M13 phage minor coat protein pIII. Phages that contain p-azidophenylalanine can undergo a highly specific azide-alkyne [3 + 2] cycloaddition reaction with ...
Hou Shaobin - - 2004
We report the complete genome sequence of the deep-sea gamma-proteobacterium, Idiomarina loihiensis, isolated recently from a hydrothermal vent at 1,300-m depth on the Loihi submarine volcano, Hawaii. The I. loihiensis genome comprises a single chromosome of 2,839,318 base pairs, encoding 2,640 proteins, four rRNA operons, and 56 tRNA genes. A ...
Grotenbreg Gijsbert M - - 2004
The synthesis of series of diversely functionalized epsilon-morpholine amino acids (MAAs, 5a-h) starting from an epsilon-sugar amino acid and following a two-step oxidative glycol cleavage/reductive amination strategy, is described. In an alternative synthetic scheme, diastereoisomerically pure delta-MAAs (12a,b) were obtained. Oligopeptides containing MAAs were prepared either by direct incorporation of ...
Buczek Olga - - 2005
The post-translational modification of an L- to a D-amino acid has been documented in relatively few gene products, mostly in small peptides under 10 amino acids in length. In this report, we demonstrate that a 46-amino acid polypeptide toxin has one D-phenylalanine at position 44, and that the epimerization from ...
Wu Ning - - 2004
We have developed a second orthogonal tRNA/synthetase pair for use in yeast based on the Escherichia coli tRNALeu/leucyl tRNA-synthetase pair. Using a novel genetic selection, we have identified a series of synthetase mutants that selectively charge the amber suppresor tRNA with the C8 amino acid, alpha-aminocaprylic acid, and the photocaged ...
Roy Hervé - - 2004
Translation of the genetic code requires attachment of tRNAs to their cognate amino acids. Errors during amino-acid activation and tRNA esterification are corrected by aminoacyl-tRNA synthetase-catalyzed editing reactions, as extensively described for aliphatic amino acids. The contribution of editing to aromatic amino-acid discrimination is less well understood. We show that ...
Zaramella Simone - - 2004
We describe the development of a solid-phase technique for the synthesis of 5'-peptide-oligonucleotide conjugates (POCs) with a uniform protection strategy for the nucleic acid and the peptide fragments. On the alpha-amino function, the amino acid building blocks were protected with the 2-(biphenyl-4-yl)propan-2-yloxycarbonyl (Bpoc) group. This protection is removed during the ...
Dembitsky Valery M - - 2004
This article describes recent developments in the synthesis and biological activity of alpha-aminoboronic acids, amine-carboxyboranes and their derivatives as potential therapeutic agents. alpha-Amino acid analogues are of considerable interest as inhibitors of enzymes involved in amino acid and peptide metabolism. In particular, alpha-amino alkylphosphonic acids and alpha-amino alkylboronic acids, in ...
Elf Johan - - 2005
The rates of consumption of different amino acids in protein synthesis are in general stoichiometrically coupled with coefficients determined by codon usage frequencies on translating ribosomes. We show that when the rates of synthesis of two or more amino acids are limiting for protein synthesis and exactly matching their coupled ...
del Amo Vicente - - 2004
Cholic acid 2a has been converted into two new orthogonally-protected triamino scaffolds, 13 and 14. The synthesis proceeds via the bis-Boc-NH-substituted azide 10, for which an improved preparation is described. After removal of the Boc groups, the two axial amines are differentiated through a novel monoprotection employing 1-(2-nitrobenzenesulfonyloxy)-benzotriazole 29. Regioselectivity ...
Leman Luke - - 2004
Almost all discussions of prebiotic chemistry assume that amino acids, nucleotides, and possibly other monomers were first formed on the Earth or brought to it in comets and meteorites, and then condensed nonenzymatically to form oligomeric products. However, attempts to demonstrate plausibly prebiotic polymerization reactions have met with limited success. ...
Fallico V - - 2004
Chemometric modeling of peptide and free amino acid data was used to study proteolysis in Protected Denomination of Origin Ragusano cheese. Twelve cheeses ripened 3 to 7 mo were selected from local farmers and were analyzed in 4 layers: rind, external, middle, and internal. Proteolysis was significantly affected by cheese ...
Garner Matthew R - - 2004
Histamine is an inflammatory agent that contributes to bovine laminitis. Cattle fed silage-containing rations often have large populations of Allisonella histaminiformans, but this obligate histidine-decarboxylating bacterium could not be isolated from cattle fed timothy hay. The growth of A. histaminiformans was stimulated by yeast extract, protein hydrolysates, and water-soluble extracts ...
Smerdka Joachim - - 2004
A novel tool for polymer-assisted solution phase (PASP) esterification of amino acid and peptide derivatives has been developed. When treated with carboxylic acids, polymer-bound alkyltriazenes react with a loss of nitrogen and transfer of the alkyl moiety to the carboxylate anion to form the corresponding alkyl esters. There are no ...
Cheng C M - - 2004
The possible role of phosphoryl amino acids for biomolecular origins is briefly reviewed. Peptide formation, ester formation, ester exchange on phosphorus and N to O migration occurred when the N-phosphoryl amino acid was incubated at room temperature. Short nucleotides and peptides were formed when nucleoside was reacted with N-phosphoryl amino ...
Moldvai István - - 2004
The first direct synthesis of (+)-lysergic acid (2a) suitable for scale-up has been achieved by the following reaction sequence. Bromoketones 4d or 4g were allowed to react with amine 5 followed by deprotection, and the resulting diketone 6c was transformed into the unsaturated ketone (+/-)-7 by the LiBr/Et(3)N system. Resolution ...
Plankensteiner Kristof - - 2004
To re-enact the long way to the origin of life with today's chemical methods, many steps have to be investigated in the light of a primordial scenario deduced from geochemical research. After the formation of our planet and its atmosphere, prebiotic chemical evolution started its course with the formation of ...
Kjellström Sven - - 2004
Phosphopeptides are often detected with low efficiency by MALDI MS analysis of peptide mixtures. In an effort to improve the phosphopeptide ion response in MALDI MS, we investigated the effects of adding low concentrations of organic and inorganic acids during peptide sample preparation in 2,5-dihydroxybenzoic acid (2,5-DHB) matrix. Phosphoric acid ...
Yang Chi Ming - - 2004
Despite considerable efforts it has remained unclear what principle governs the selection of the 20 canonical amino acids in the genetic code. Based on a previous study of the 28-gonal and rotational symmetric arrangement of the 20 amino acids in the genetic code, new analyses of the organization of the ...
Wang Jianyao - - 2004
A novel technique to study the reactivity of acyl glucuronide metabolites to protein has been developed and is described herein. Considered here are acyl glucuronide metabolites, which have undergone the rearrangement of the glucuronic acid moiety at physiological temperature and pH. The investigation of the reactivity of these electrophilic metabolites ...
Taylor Lynn - - 2004
The intent of this review is to provide a broad overview of the interorgan metabolism of glutamine and to discuss in more detail its role in acid-base balance. Muscle, adipose tissue, and the lungs are the primary sites of glutamine synthesis and release. During normal acid-base balance, the small intestine ...
Blight Sherry K - - 2004
Pyrrolysine is the 22nd amino acid. An unresolved question has been how this atypical genetically encoded residue is inserted into proteins, because all previously described naturally occurring aminoacyl-tRNA synthetases are specific for one of the 20 universally distributed amino acids. Here we establish that synthetic L-pyrrolysine is attached as a ...
Cavalcanti Andre R O - - 2004
The division of the aminoacyl-tRNA synthetases in two classes is compared with a division of the amino acids in two classes, obtained from the AAIndex databank by a principal component analysis. The division of the enzymes in Classes I and II follows to a great extent a division in the ...
Panke Sven - - 2004
Biocatalysis has become an established technology for the industrial manufacture of fine chemicals. In recent years, a multitude of chemical companies have embraced biocatalysis for the manufacture of desired stereoisomers, and new or improved methods for the synthesis of enantiomerically pure alpha- and beta-amino acids, amines, amides, peptides, nitriles, alcohols, ...
Braunstein Amir - - 2004
We report that intravenous injection (3 mg/kg of body weight twice daily) of a diastereomer (containing 33% D amino acids) of an antimicrobial peptide, K6L9 (LKLLKKLLKKLLKLL-NH2), but not the all-L-amino-acid parental peptide, cures neutropenic mice infected with gentamicin-sensitive Pseudomonas aeruginosa and gentamicin-resistant Acinetobacter baumannii bacteria. Various biophysical experiments suggest a ...
Zaia D A M - - 2004
Minerals more readily adsorb amino acids with charged R groups than uncharged R groups, so that the incorporation of amino acids with charged R groups into peptides would be more frequent than for amino acids with uncharged R groups. However, 74% of the amino acids in the proteins of modern ...
Douat-Casassus Céline - - 2004
Peptide dendrimers incorporating 3,5-diaminobenzoic acid 1 as a branching unit (B) were prepared by solid-phase synthesis of ((Ac-A(3))(2)B-A(2))(2)B-Cys-A(1)-NH(2) followed by disulfide bridge formation. Twenty-one homo- and heterodimeric dendrimers were obtained by permutations of aspartate, histidine, and serine at positions A(1), A(2), and A(3). Two dendrimers catalyzed the hydrolysis of 7-hydroxy-N-methyl-quinolinium ...
Klipcan Liron - - 2004
The aminoacyl-tRNA synthetases (aaRSs) ensure the fidelity of the translation of the genetic code, covalently attaching appropriate amino acids to the corresponding nucleic acid adaptor molecules-tRNA. The fundamental role of aminoacylation reaction catalysed by aaRSs implies that representatives of the family are thought to be among the earliest proteins to ...
Owen S M - - 2004
The ability of certain theta-defensins, including retrocyclin-1, to protect human cells from infection by HIV-1 marks them as potentially useful molecules. Theta-defensins composed of L-amino acids are likely to be unstable in environments that contain host and microbial proteases. This study compared the properties of two enantiomeric theta-defensins, retrocyclin-1, and ...
Li Zhaolong - - 2004
The reactive intermediates of pentacoordinated phosphoranes with amino acids (P(5)-AA) as building blocks, which were obtained by the reaction of O-phenylene phosphorochloridate with N,O-bis(trimethylsilyl)amino acids, were linked to a solid-phase support containing a hydroxymethyl polystyrene functional group. The first amino acid residue was coupled to the solid-phase support after washing ...
Anderson J Christopher - - 2004
With few exceptions the genetic codes of all known organisms encode the same 20 amino acids, yet all that is required to add a new building block are a unique tRNA/aminoacyl-tRNA synthetase pair, a source of the amino acid, and a unique codon that specifies the amino acid. For example, ...
Cernovská Katerina - - 2004
Pyrazole amino acid oligoamides were prepared on polyethylene glycol starting from nitro pyrazole carboxylic acids or protected pyrazole amino acids. The polymer support facilitates product isolation during synthesis and makes the target oligoamides soluble in chloroform and water. This allows the determination of their binding properties towards peptides. Moderate affinity, ...
Francesconi Lynn C - - 2004
[99mTcO] apcitide (99mTcO(P246)), the technetium complex of the 13 amino acid, apcitide, cyclo-(D-Tyr-Apc-Gly-Asp-Cys)-Gly-Gly-Cys(Acm)-Gly-Cys(Acm)-Gly-Gly-Cys-NH2, where Apc is L-[S-(3-aminopropyl)]cysteine (an arginine mimetic) and Acm is the acetamidomethyl protecting group, has high affinity and selectivity for the GPIIb/IIIa receptor that is expressed on the membrane surface of activated platelets and plays an integral ...
Podstawka Edyta - - 2004
Surface-enhanced Raman scattering spectra (SERS) were measured for various amino acids: L-methionine (Met), L-cysteine (Cys), Lglycine (Gly), L-leucine (Leu), L-phenylalanine (Phe), and L-proline (Pro) and their homodipeptides (Met-Met, Cys-Cys, Gly-Gly, LeuLeu, Phe-Phe, and Pro-Pro) in silver colloidal solutions. The geometry and orientation of the amino acids or dipeptides on the ...
Anbalagan V - - 2004
The aim of this study was to investigate the dissociation patterns, and in particular the relative abundance of [b(3) + 17 + Cat](+), for peptides with C-termini designed to allow transfer of the -OH required to generate the product ion, but not necessarily as the most favored pathway. Working with ...
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