The search for novel and effective therapeutics for Alzheimer's disease (AD) is the main quest that remains to be resolved. The goal is to find a disease-modifying agent able to confront the multifactorial nature of the disease positively. Herewith, a family of huprineY-tryptophan heterodimers was prepared, resulting in inhibition of cholinesterase and neuronal nitric oxide synthase enzymes, with effect against amyloid-beta (Aβ) and potential ability to cross the blood-brain barrier. Their cholinesterase pattern of behavior was inspected using kinetic analysis in tandem with docking studies. These heterodimers exhibited a promising pharmacological profile with strong implication in AD.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• Alzheimerova nemoc farmakoterapie   metabolismus   MeSH
• aminochinoliny chemie   farmakologie   MeSH
• amyloidní beta-protein antagonisté a inhibitory   metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• heterocyklické sloučeniny tetra- a více cyklické chemie   farmakologie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• neuroprotektivní látky chemická syntéza   chemie   farmakologie   MeSH
• tryptofan chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The effective concentration of a drug in the blood, i.e. the concentration of a free drug in the blood, is influenced by the strength of drug binding onto plasma proteins. Besides its efficacy, these interactions subsequently influence the liberation, absorption, distribution, metabolism, excretion, and toxicological properties of the drug. It is important to not only determine the binding strength and stoichiometry, but also the binding site of a drug on the plasma protein molecule, because the co-administration of drugs with the same binding site can affect the above-mentioned concentration and as a result the pharmacological behavior of the drugs and lead to side effects caused by the change in free drug concentration, its toxicity. In this study, the binding characteristics of six drugs with human serum albumin, the most abundant protein in human plasma, were determined by capillary electrophoresis-frontal analysis, and the obtained values of binding parameters were compared with the literature data. The effect of several drugs and site markers on the binding of l-tryptophan and lidocaine to human serum albumin was investigated in subsequent displacement studies which thus demonstrated the usability of capillary electrophoresis as an automated high-throughput screening method for drug-protein binding studies.

• MeSH
• chlorpropamid analýza   farmakologie   MeSH
• diklofenak analýza   farmakologie   MeSH
• elektroforéza kapilární MeSH
• fenylbutazon analýza   farmakologie   MeSH
• flurbiprofen analýza   farmakologie   MeSH
• ibuprofen analýza   farmakologie   MeSH
• lidé MeSH
• lidokain antagonisté a inhibitory   chemie   MeSH
• lidský sérový albumin chemie   MeSH
• tolbutamid analýza   farmakologie   MeSH
• tryptofan antagonisté a inhibitory   chemie   MeSH
• vazebná místa účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

A combination of tacrine and tryptophan led to the development of a new family of heterodimers as multi-target agents with potential to treat Alzheimer's disease. Based on the in vitro biological profile, compound S-K1035 was found to be the most potent inhibitor of human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE), demonstrating balanced IC50 values of 6.3 and 9.1 nM, respectively. For all the tacrine-tryptophan heterodimers, favorable inhibitory effect on hAChE as well as on hBChE was coined to the optimal spacer length ranging from five to eight carbon atoms between these two pharmacophores. S-K1035 also showed good ability to inhibit Aβ42 self-aggregation (58.6 ± 5.1% at 50 μM) as well as hAChE-induced Aβ40 aggregation (48.3 ± 6.3% at 100 μM). The X-ray crystallographic analysis of TcAChE in complex with S-K1035 pinpointed the utility of the hybridization strategy applied and the structures determined with the two K1035 enantiomers in complex with hBChE could explain the higher inhibition potency of S-K1035. Other in vitro evaluations predicted the ability of S-K1035 to cross blood-brain barrier and to exert a moderate inhibition potency against neuronal nitric oxide synthase. Based on the initial promising biochemical data and a safer in vivo toxicity compared to tacrine, S-K1035 was administered to scopolamine-treated rats being able to dose-dependently revert amnesia.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• Alzheimerova nemoc farmakoterapie   metabolismus   MeSH
• amyloidní beta-protein antagonisté a inhibitory   metabolismus   MeSH
• bludiště - učení účinky léků   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• ligandy MeSH
• molekulární struktura MeSH
• neuroprotektivní látky chemická syntéza   chemie   farmakologie   MeSH
• potkani Wistar MeSH
• proteinové agregáty účinky léků   MeSH
• takrin chemie   farmakologie   MeSH
• tryptofan chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Protein-carbohydrate interactions are very often mediated by the stacking CH-π interactions involving the side chains of aromatic amino acids such as tryptophan (Trp), tyrosine (Tyr) or phenylalanine (Phe). Especially suitable for stacking is the Trp residue. Analysis of the PDB database shows Trp stacking for 265 carbohydrate or carbohydrate like ligands in 5 208 Trp containing motives. An appropriate model system to study such an interaction is the AAL lectin family where the stacking interactions play a crucial role and are thought to be a driving force for carbohydrate binding. In this study we present data showing a novel finding in the stacking interaction of the AAL Trp side chain with the carbohydrate. High resolution X-ray structure of the AAL lectin from Aleuria aurantia with α-methyl-l-fucoside ligand shows two possible Trp side chain conformations with the same occupation in electron density. The in silico data shows that the conformation of the Trp side chain does not influence the interaction energy despite the fact that each conformation creates interactions with different carbohydrate CH groups. Moreover, the PDB data search shows that the conformations are almost equally distributed across all Trp-carbohydrate complexes, which would suggest no substantial preference for one conformation over another.

• MeSH
• databáze proteinů MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• lektiny chemie   metabolismus   MeSH
• metabolismus sacharidů * MeSH
• tryptofan chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Singlet molecular oxygen ((1)O2) contributes to protein damage triggering biophysical and biochemical changes that can be related with aging and oxidative stress. Serum albumins, such as bovine serum albumin (BSA), are abundant proteins in blood plasma with different biological functions. This paper presents a kinetic and spectroscopic study of the (1)O2-mediated oxidation of BSA using the tris(2,2'-bipyridine)ruthenium(II) cation [Ru(bpy)3](2+) as sensitizer. BSA quenches efficiently (1)O2 with a total (chemical+physical interaction) rate constant kt(BSA)=7.3(±0.4)×10(8)M(-1)s(-1), where the chemical pathway represented 37% of the interaction. This efficient quenching by BSA indicates the participation of several reactive residues. MALDI-TOF MS analysis of intact BSA confirmed that after oxidation by (1)O2, the mass protein increased the equivalent of 13 oxygen atoms. Time-resolved emission spectra analysis of BSA established that Trp residues were oxidized to N'-formylkynurenine, being the solvent-accessible W134 preferentially oxidized by (1)O2 as compared with the buried W213. MS confirmed oxidation of at least two Tyr residues to form dihydroxyphenylalanine, with a global reactivity towards (1)O2 six-times lower than for Trp residues. Despite the lack of MS evidences, kinetic and chemical analysis also suggested that residues other than Trp and Tyr, e.g. Met, must react with (1)O2. Modeling of the 3D-structure of BSA indicated that the oxidation pattern involves a random distribution of (1)O2 into BSA; allowing also the interaction of (1)O2 with buried residues by its diffusion from the bulk solvent through interconnected internal hydrophilic and hydrophobic grooves.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   farmakologie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kinetika MeSH
• oxidace-redukce MeSH
• oxidační stres * MeSH
• sérový albumin hovězí chemie   metabolismus   MeSH
• singletový kyslík chemie   metabolismus   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• stárnutí metabolismus   patologie   MeSH
• tryptofan chemie   metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH

The bilirubin (BR) photo-conversion in the human body is a protein-dependent process; an effective photo-isomerization of the potentially neurotoxic Z,Z-BR as well as its oxidation to biliverdin in the antioxidant redox cycle is possible only when BR is bound on serum albumin. We present a novel analytical concept in the study of linear tetrapyrroles metabolic processes based on an in-depth mapping of binding sites in the structure of human serum albumin (HSA). A combination of fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling methods was used for recognition of the binding site for BR, its derivatives (mesobilirubin and bilirubin ditaurate), and the products of the photo-isomerization and oxidation (lumirubin, biliverdin, and xanthobilirubic acid) on HSA. The CD spectra and fluorescent quenching of the Trp-HSA were used to calculate the binding constants. The results of the CD displacement experiments performed with hemin were interpreted together with the findings of molecular docking performed on the pigment-HSA complexes. We estimated that Z,Z-BR and its metabolic products bind on two independent binding sites. Our findings support the existence of a reversible antioxidant redox cycle for BR and explain an additional pathway of the photo-isomerization process (increase of HSA binding capacity; the excess free [unbound] BR can be converted and also bound to HSA).

• MeSH
• bilirubin analogy a deriváty   chemie   metabolismus   MeSH
• biliverdin analogy a deriváty   chemie   metabolismus   MeSH
• cirkulární dichroismus MeSH
• fluorescenční spektrometrie MeSH
• fotochemické procesy * MeSH
• kompetitivní vazba MeSH
• lidé MeSH
• ligandy MeSH
• molekulární konformace MeSH
• molekulární modely * MeSH
• oxidace-redukce MeSH
• sérový albumin chemie   metabolismus   MeSH
• simulace molekulového dockingu MeSH
• stereoizomerie MeSH
• taurin analogy a deriváty   chemie   metabolismus   MeSH
• tryptofan chemie   MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Despite a great interest in Malassezia yeasts their metabolism is still little known. Most studied is their lipid metabolism. Only recently it was found that Malassezia produces pigments derived from tryptophan, which play a role in the pathogenesis of skin diseases. Malassezin synergism with other indole pigments is considered to be the cause of clinical manifestation of pityriasis versicolor such as hypopigmentation, lesions resistant to UV radiation and decreased expression of inflammatory response.

• MeSH
• biologické pigmenty chemie   MeSH
• fosfolipasy metabolismus   MeSH
• hyperpigmentace etiologie   MeSH
• lidé MeSH
• lipasa metabolismus   MeSH
• lipidy diagnostické užití   fyziologie   MeSH
• Malassezia * cytologie   chemie   metabolismus   MeSH
• melaniny chemie   MeSH
• pityriáza patofyziologie   MeSH
• seboroická dermatitida etiologie   MeSH
• tryptofan analogy a deriváty   chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Amino acid sequence and environment are the most important factors determining the structure, stability and dynamics of proteins. To evaluate their roles in the process of folding, we studied a retroversion of the well-described Trp-cage miniprotein in water and 2,2,2-trifluoroethanol (TFE) solution. We show, by circular dichroism spectroscopy and nuclear magnetic resonance (NMR) measurement, that the molecule has no stable structure under conditions in which the Trp-cage is folded. A detectable stable structure of the retro Trp-cage, with the architecture similar to that of the original Trp-cage, is established only upon addition of TFE to 30% of the total solvent volume. The retro Trp-cage structure shows a completely different pattern of stabilizing contacts between amino acid residues, involving the guanidinium group of arginine and the aromatic group of tryptophan. The commonly used online prediction methods for protein and peptide structures Robetta and PEP-FOLD failed to predict that the retro Trp-cage is unstructured under default prediction conditions. On the other hand, both methods provided structures with a fold similar to those of the experimentally determined NMR structure in water/TFE but with different contacts between amino acids.

• MeSH
• arginin chemie   MeSH
• molekulární sekvence - údaje MeSH
• peptidy chemická syntéza   chemie   MeSH
• sbalování proteinů MeSH
• sekundární struktura proteinů MeSH
• sekvence aminokyselin MeSH
• simulace molekulární dynamiky MeSH
• stabilita proteinů MeSH
• statická elektřina MeSH
• termodynamika MeSH
• trifluorethanol chemie   MeSH
• tryptofan chemie   MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The peptide named codesane (COD), consisting of 18 amino acid residues and isolated from the venom of wild bee Colletes daviesanus (Hymenoptera : Colletidae), falls into the category of cationic α-helical amphipathic antimicrobial peptides. In our investigations, synthetic COD exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and Candida albicans but also noticeable hemolytic activity. COD and its analogs (collectively referred to as CODs) were studied for the mechanism of their action. The interaction of CODs with liposomes led to significant leakage of calcein entrapped in bacterial membrane-mimicking large unilamellar vesicles made preferentially from anionic phospholipids while no calcein leakage was observed from zwitterionic liposomes mimicking membranes of erythrocytes. The preference of CODs for anionic phospholipids was also established by the blue shift in the tryptophan emission spectra maxima when the interactions of tryptophan-containing COD analogs with liposomes were examined. Those results were in agreement with the antimicrobial and hemolytic activities of CODs. Moreover, we found that the studied peptides permeated both the outer and inner cytoplasmic membranes of Escherichia coli. This was determined by measuring changes in the fluorescence of probe N-phenyl-1-naphthylamine and detecting cytoplasmic β-galactosidase released during the interaction of peptides with E. coli cells. Transmission electron microscopy revealed that treatment of E. coli with one of the COD analogs caused leakage of bacterial content mainly from the septal areas of the cells.

• MeSH
• antibakteriální látky chemická syntéza   izolace a purifikace   farmakologie   MeSH
• Escherichia coli účinky léků   metabolismus   ultrastruktura   MeSH
• fluorescence MeSH
• fosfolipidy metabolismus   MeSH
• hemolýza účinky léků   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kationické antimikrobiální peptidy genetika   izolace a purifikace   farmakologie   MeSH
• liposomy metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• permeabilita buněčné membrány účinky léků   MeSH
• racionální návrh léčiv MeSH
• sekundární struktura proteinů MeSH
• sekvence aminokyselin MeSH
• transmisní elektronová mikroskopie MeSH
• tryptofan chemie   MeSH
• včelí jedy chemie   genetika   izolace a purifikace   farmakologie   MeSH
• včely genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The retention and splicing (RES) complex is a conserved spliceosome-associated module that was shown to enhance splicing of a subset of transcripts and promote the nuclear retention of unspliced pre-mRNAs in yeast. The heterotrimeric RES complex is organized around the Snu17p protein that binds to both the Bud13p and Pml1p subunits. Snu17p exhibits an RRM domain that resembles a U2AF homology motif (UHM) and Bud13p harbors a Trp residue reminiscent of an UHM-ligand motif (ULM). It has therefore been proposed that the interaction between Snu17p and Bud13p resembles canonical UHM-ULM complexes. Here, we have used biochemical and NMR structural analysis to characterize the structure of the yeast Snu17p-Bud13p complex. Unlike known UHMs that sequester the Trp residue of the ULM ligand in a hydrophobic pocket, Snu17p and Bud13p utilize a large interaction surface formed around the two helices of the Snu17p domain. In total 18 residues of the Bud13p ligand wrap around the Snu17p helical surface in an U-turn-like arrangement. The invariant Trp(232) in Bud13p is located in the center of the turn, and contacts surface residues of Snu17p. The structural data are supported by mutational analysis and indicate that Snu17p provides an extended binding surface with Bud13p that is notably distinct from canonical UHM-ULM interactions. Our data highlight structural diversity in RRM-protein interactions, analogous to the one seen for nucleic acid interactions.

• MeSH
• Escherichia coli genetika   metabolismus   MeSH
• exprese genu MeSH
• fosforylace MeSH
• fungální RNA biosyntéza   genetika   MeSH
• hydrofobní a hydrofilní interakce MeSH
• interakční proteinové domény a motivy MeSH
• malý jaderný ribonukleoprotein U2 chemie   genetika   metabolismus   MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• prekurzory RNA biosyntéza   genetika   MeSH
• rekombinantní proteiny chemie   genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   genetika   metabolismus   MeSH
• Saccharomyces cerevisiae chemie   genetika   metabolismus   MeSH
• sekundární struktura proteinů MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• sestřih RNA MeSH
• spliceozomy chemie   metabolismus   MeSH
• transportní proteiny chemie   genetika   metabolismus   MeSH
• tryptofan chemie   metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH