Tryptophan-derived metabolites, a group of neurotransmitters essential for various brain functions, play key roles in regulating mood, movement, sleep, and cognition. However, the comprehensive characterisation of tryptophan-melatonin pathway metabolites is challenging due to factors such as their structural diversity, chemical complexity, low concentrations, and instability of these metabolites. In this study, we developed and validated an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) methodology with electrospray ionisation for the simultaneous separation and quantification of tryptophan metabolites in human plasma. The analytical calibration ranges in plasma were 0.50-200 ng/mL for serotonin, 0.01-5 ng/mL for N-acetylserotonin, 0.01-20 ng/mL for tryptamine, 0.01-20 ng/mL for 6-sulfatoxymelatonin, 0.01-20 ng/mL for 6-hydroxymelatonin, 0.01-100 ng/mL for melatonin, and 0.10-20 ng/mL for N-acetyltryptamine, with correlation coefficients ranging from 0.954 for N-acetyltryptamine to 0.997 for tryptamine. The intraday and interday precision remained consistently below 15 % for all analytes. Most analytes met the accuracy criteria, except for N-acetyltryptamine at the lowest quality control level (0.2 ng/mL), where the intraday and interday accuracy were 22.4 % and 17.4 %, respectively. In conclusion, this novel method allows for rapid identification of tryptophan-melatonin pathway intermediates in less than ten minutes, including seven distinct melatonin-related analytes. This suggests that it may find use in everyday clinical and scientific endeavours.
- Klíčová slova
- Liquid chromatography, Mass spectrometry, Melatonin, Plasma, Tryptophan metabolites,
- MeSH
- lidé MeSH
- limita detekce MeSH
- lineární modely MeSH
- melatonin * krev analogy a deriváty metabolismus chemie MeSH
- reprodukovatelnost výsledků MeSH
- serotonin krev analogy a deriváty MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- tryptaminy krev MeSH
- tryptofan * krev metabolismus chemie MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- melatonin * MeSH
- N-acetylserotonin MeSH Prohlížeč
- serotonin MeSH
- tryptaminy MeSH
- tryptofan * MeSH
Reactive N-hydroxy-9-azabicyclo[3.3.1]nonane (ABNOH) linked 2'-deoxyuridine 5'-O-mono- and triphosphates were synthesized through a CuAAC reaction of ABNOH-PEG4-N3 with 5-ethynyl-dUMP or -dUTP. The modified triphosphate was used as substrate for enzymatic synthesis of modified DNA probes with KOD XL DNA polymerase. The keto-ABNO radical reacted with tryptophan (Trp) and Trp-containing peptides to form a stable tricyclic fused hexahydropyrrolo-indole conjugates. Similarly modified ABNOH-linked nucleotides reacted with Trp-containing peptides to form a stable conjugate in the presence but surprisingly even in the absence of NaNO2 (presumably through activation by O2). The reactive ABNOH-modified DNA probe was used for bioconjugations and crosslinking with Trp-containing peptides or proteins.
- Klíčová slova
- Bioconjugations, N-oxyl radicals, Nucleotides, Oligonucleotides, Peptides,
- MeSH
- DNA-dependentní DNA-polymerasy metabolismus chemie MeSH
- DNA * chemie MeSH
- nukleotidy * chemie MeSH
- peptidy * chemie MeSH
- proteiny chemie MeSH
- reagencia zkříženě vázaná chemie MeSH
- tryptofan * chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- DNA-dependentní DNA-polymerasy MeSH
- DNA * MeSH
- nukleotidy * MeSH
- peptidy * MeSH
- proteiny MeSH
- reagencia zkříženě vázaná MeSH
- tryptofan * MeSH
This Concept short review offers an insightful analysis of pivotal research papers and explores the key synthetic ideas behind the intersection of two realms in peptide chemistry: using tryptophan and Petasis multicomponent reactions for macrocyclisation and labelling of peptides. The recently published tryptophan-mediated Petasis reaction (TMPR) concept represents a critical junction between these two worlds, highlighting how combining such methodologies leads to more effective and versatile synthetic strategies, setting a potentially new direction for future research in the field of peptide-drug conjugates.
- Klíčová slova
- Petasis reaction, multicomponent reactions, peptide labelling, peptide stapling, tryptophan,
- MeSH
- cyklizace MeSH
- molekulární struktura MeSH
- peptidy * chemie MeSH
- tryptofan * chemie MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- peptidy * MeSH
- tryptofan * MeSH
Electron transfer (ET) between neutral and cationic tryptophan residues in the azurin construct [ReI(H126)(CO)3(dmp)](W124)(W122)CuI (dmp = 4,7-Me2-1,10-phenanthroline) was investigated by Born-Oppenheimer quantum-mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) simulations. We focused on W124•+ ← W122 ET, which is the middle step of the photochemical hole-hopping process *ReII(CO)3(dmp•-) ← W124 ← W122 ← CuI, where sequential hopping amounts to nearly 10,000-fold acceleration over single-step tunneling (ACS Cent. Sci. 2019, 5, 192-200). In accordance with experiments, UKS-DFT QM/MM/MD simulations identified forward and reverse steps of W124•+ ↔ W122 ET equilibrium, as well as back ET ReI(CO)3(dmp•-) → W124•+ that restores *ReII(CO)3(dmp•-). Strong electronic coupling between the two indoles (≥40 meV in the crossing region) makes the productive W124•+ ← W122 ET adiabatic. Energies of the two redox states are driven to degeneracy by fluctuations of the electrostatic potential at the two indoles, mainly caused by water solvation, with contributions from the protein dynamics in the W122 vicinity. ET probability depends on the orientation of Re(CO)3(dmp) relative to W124 and its rotation diminishes the hopping yield. Comparison with hole hopping in natural systems reveals structural and dynamics factors that are important for designing efficient hole-hopping processes.
- MeSH
- azurin * chemie MeSH
- indoly MeSH
- oxidace-redukce MeSH
- transport elektronů MeSH
- tryptofan chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- azurin * MeSH
- indoly MeSH
- tryptofan MeSH
The acylated Repeats in ToXins (RTX) leukotoxins, the adenylate cyclase toxin (CyaA) or α-hemolysin (HlyA), bind β2 integrins of leukocytes but also penetrate cells lacking these receptors. We show that the indoles of conserved tryptophans in the acylated segments, W876 of CyaA and W579 of HlyA, are crucial for β2 integrin-independent membrane penetration. Substitutions of W876 by aliphatic or aromatic residues did not affect acylation, folding, or the activities of CyaA W876L/F/Y variants on cells expressing high amounts of the β2 integrin CR3. However, toxin activity of CyaA W876L/F/Y on cells lacking CR3 was strongly impaired. Similarly, a W579L substitution selectively reduced HlyA W579L cytotoxicity towards cells lacking β2 integrins. Intriguingly, the W876L/F/Y substitutions increased the thermal stability (Tm) of CyaA by 4 to 8 °C but locally enhanced the accessibility to deuteration of the hydrophobic segment and of the interface of the two acylated loops. W876Q substitution (showing no increase in Tm), or combination of W876F with a cavity-filling V822M substitution (this combination decreasing the Tm closer to that of CyaA), yielded a milder defect of toxin activity on erythrocytes lacking CR3. Furthermore, the activity of CyaA on erythrocytes was also selectively impaired when the interaction of the pyrrolidine of P848 with the indole of W876 was ablated. Hence, the bulky indoles of residues W876 of CyaA, or W579 of HlyA, rule the local positioning of the acylated loops and enable a membrane-penetrating conformation in the absence of RTX toxin docking onto the cell membrane by β2 integrins.
- Klíčová slova
- RTX toxin, acylated segment, adenylate cyclase toxin, cytotoxicity, hydrogen/deuterium exchange, thermal stability, tryptophan residue, α-hemolysin, β(2) integrins,
- MeSH
- adenylátcyklasový toxin * chemie genetika metabolismus MeSH
- antigeny CD18 * genetika metabolismus MeSH
- Bordetella pertussis MeSH
- buněčná membrána metabolismus MeSH
- erytrocyty metabolismus MeSH
- konzervovaná sekvence MeSH
- tryptofan * chemie genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- adenylátcyklasový toxin * MeSH
- antigeny CD18 * MeSH
- tryptofan * MeSH
Most of the structural proteins known today are composed of domains that carry their own functions while keeping their structural properties. It is supposed that such domains, when taken out of the context of the whole protein, can retain their original structure and function to a certain extent. Information on the specific functional and structural characteristics of individual domains in a new context of artificial fusion proteins may help to reveal the rules of internal and external domain communication. Moreover, this could also help explain the mechanism of such communication and address how the mutual allosteric effect plays a role in a such multi-domain protein system. The simple model system of the two-domain fusion protein investigated in this work consisted of a well-folded PDZ3 domain and an artificially designed small protein domain called Tryptophan Cage (TrpCage). Two fusion proteins with swapped domain order were designed to study their structural and functional features as well as their biophysical properties. The proteins composed of PDZ3 and TrpCage, both identical in amino acid sequence but different in composition (PDZ3-TrpCage, TrpCage-PDZ3), were studied using circualr dichroism (CD) spectrometry, analytical ultracentrifugation, and molecular dynamic simulations. The biophysical analysis uncovered different structural and denaturation properties of both studied proteins, revealing their different unfolding pathways and dynamics.
- Klíčová slova
- chimeras, fusion protein, protein domains, protein dynamic studies,
- MeSH
- PDZ domény * genetika fyziologie MeSH
- rekombinantní fúzní proteiny * chemie genetika metabolismus MeSH
- sekvence aminokyselin MeSH
- simulace molekulární dynamiky MeSH
- tryptofan * chemie genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- rekombinantní fúzní proteiny * MeSH
- tryptofan * MeSH
In an effort to establish reliable thermodynamic data for proteinogenic amino acids, heat capacities for l-histidine (CAS RN: 71-00-1), l-phenylalanine (CAS RN: 63-91-2), l-proline (CAS RN: 147-85-3), l-tryptophan (CAS RN: 73-22-3), and l-tyrosine (CAS RN: 60-18-4) were measured over a wide temperature range. Prior to heat capacity measurements, thermogravimetric analysis was performed to determine the decomposition temperatures while X-ray powder diffraction (XRPD) and heat-flux differential scanning calorimetry (DSC) were used to identify the initial crystal structures and their possible transformations. Crystal heat capacities of all five amino acids were measured by Tian-Calvet calorimetry in the temperature interval from 262 to 358 K and by power compensation DSC in the temperature interval from 307 to 437 K. Experimental values determined in this work were then combined with the literature data obtained by adiabatic calorimetry. Low temperature heat capacities of l-histidine, for which no literature data were available, were determined in this work using the relaxation (heat pulse) calorimetry from 2 K. As a result, isobaric crystal heat capacities and standard thermodynamic functions up to 430 K for all five crystalline amino acids were developed.
- Klíčová slova
- crystal heat capacity, l-histidine, l-phenylalanine, l-proline, l-tryptophan, l-tyrosine, thermodynamic functions,
- MeSH
- fenylalanin chemie MeSH
- histidin chemie MeSH
- prolin chemie MeSH
- termodynamika MeSH
- tryptofan chemie MeSH
- tyrosin chemie MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fenylalanin MeSH
- histidin MeSH
- prolin MeSH
- tryptofan MeSH
- tyrosin MeSH
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.
- Klíčová slova
- Acetylcholinesterase, Alzheimer's disease, Amyloid-beta, Multi-target directed ligands, huprine Y, l-Tryptophan,
- 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
- Názvy látek
- acetylcholinesterasa MeSH
- aminochinoliny MeSH
- amyloidní beta-protein MeSH
- cholinesterasové inhibitory MeSH
- heterocyklické sloučeniny tetra- a více cyklické MeSH
- huprine Y MeSH Prohlížeč
- neuroprotektivní látky MeSH
- tryptofan MeSH
Hole hopping through tryptophan/tyrosine chains enables rapid unidirectional charge transport over long distances. We have elucidated structural and dynamical factors controlling hopping speed and efficiency in two modified azurin constructs that include a rhenium(I) sensitizer, Re(His)(CO)3(dmp)+, and one or two tryptophans (W1, W2). Experimental kinetics investigations showed that the two closely spaced (3 to 4 Å) intervening tryptophans dramatically accelerated long-range electron transfer (ET) from CuI to the photoexcited sensitizer. In our theoretical work, we found that time-dependent density-functional theory (TDDFT) quantum mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) trajectories of low-lying triplet excited states of ReI(His)(CO)3(dmp)+-W1(-W2) exhibited crossings between sensitizer-localized (*Re) and charge-separated [ReI(His)(CO)3(dmp•-)/(W1•+ or W2•+)] (CS1 or CS2) states. Our analysis revealed that the distances, angles, and mutual orientations of ET-active cofactors fluctuate in a relatively narrow range in which the cofactors are strongly coupled, enabling adiabatic ET. Water-dominated electrostatic field fluctuations bring *Re and CS1 states to a crossing where *Re(CO)3(dmp)+←W1 ET occurs, and CS1 becomes the lowest triplet state. ET is promoted by solvation dynamics around *Re(CO)3(dmp)+(W1); and CS1 is stabilized by Re(dmp•-)/W1•+ electron/hole interaction and enhanced W1•+ solvation. The second hop, W1•+←W2, is facilitated by water fluctuations near the W1/W2 unit, taking place when the electrostatic potential at W2 drops well below that at W1•+ Insufficient solvation and reorganization around W2 make W1•+←W2 ET endergonic, shifting the equilibrium toward W1•+ and decreasing the charge-separation yield. We suggest that multiscale TDDFT/MM/MD is a suitable technique to model the simultaneous evolution of photogenerated excited-state manifolds.
- Klíčová slova
- azurin, electron transfer, hole hopping, molecular dynamics, tryptophan,
- MeSH
- azurin chemie genetika MeSH
- elektrony MeSH
- fotochemie MeSH
- kvantová teorie MeSH
- oxidace-redukce MeSH
- Pseudomonas aeruginosa metabolismus MeSH
- rhenium chemie MeSH
- simulace molekulární dynamiky MeSH
- statická elektřina MeSH
- transport elektronů MeSH
- tryptofan chemie MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- azurin MeSH
- rhenium MeSH
- tryptofan MeSH
- voda 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.
- Klíčová slova
- binding constant, binding sites, capillary electrophoresis-frontal analysis, drug competition, human serum albumin,
- 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
- Názvy látek
- chlorpropamid MeSH
- diklofenak MeSH
- fenylbutazon MeSH
- flurbiprofen MeSH
- ibuprofen MeSH
- lidokain MeSH
- lidský sérový albumin MeSH
- tolbutamid MeSH
- tryptofan MeSH
