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[PMID]:29367489
[Au] Autor:Ogura T; Sato T; Abe M; Okano T
[Ad] Endereço:Research & Development Headquarters, LION Corporation.
[Ti] Título:Small Angle X-ray Scattering and Electron Spin Resonance Spectroscopy Study on Fragrance Infused Cationic Vesicles Modeling Scent-Releasing Fabric Softeners.
[So] Source:J Oleo Sci;67(2):177-186, 2018 Feb 01.
[Is] ISSN:1347-3352
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:Industrially relevant systems for household and personal-care products often involve a large number of components. Such multiple component formulations are indispensable and effective for functionalization of the products, but may simultaneously provide more complex structural features compared to those in ideal systems comprising a smaller number of highly pure substances. Using cryogenic transmission electron microscopy (cryo-TEM), small angle X-ray scattering (SAXS), and electron spin resonance (ESR) spectroscopy, we have investigated effects of fragrance-incorporation into cationic vesicles on their bilayer structures and membrane-membrane interactions. Cationic vesicles were prepared from TEQ surfactant, whose major component was di(alkyl fatty ester) quaternary ammonium methosulfate, and fragrance components, l-menthol, linalool, and d-limonene, were infused into the vesicle membranes to model scent-releasing fabric softeners. The cryo-TEM images confirm formation of multilamellar vesicles (MLVs). Generalized indirect Fourier transformation (GIFT) analysis of the SAXS intensities based on the modified Caillé structure factor model reveals that incorporation of a more hydrophobic fragrance component leads to a more pronounced increase of the surface separation (water layer thickness). Furthermore, the fragrance-infused systems show longer-range order of the bilayer correlations and enhanced undulation fluctuation of the membranes than those in the TEQ alone system. The spin-label ESR results indicate different restricted molecular motions in the TEQ bilayers depending on the labeled position and their marked changes upon addition of the fragrance components, suggesting different mixing schemes and solubilization positions of the fragrance molecules in the TEQ bilayers. The present data have demonstrated how the infused fragrance molecules having different hydrophobicity and molecular architectures into the cationic vesicles affect the membrane structures and the intermembrane interactions, which may provide useful information for precisely controlling a fragrance-releasing property.
[Mh] Termos MeSH primário: Cicloexenos/química
Espectroscopia de Ressonância de Spin Eletrônica
Mentol/química
Monoterpenos/química
Odorantes
Espalhamento a Baixo Ângulo
Terpenos/química
Difração de Raios X
[Mh] Termos MeSH secundário: Cátions
Interações Hidrofóbicas e Hidrofílicas
Bicamadas Lipídicas
Membranas Artificiais
Microscopia Eletrônica de Transmissão
Compostos Orgânicos/química
Compostos de Amônio Quaternário/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cations); 0 (Cyclohexenes); 0 (Lipid Bilayers); 0 (Membranes, Artificial); 0 (Monoterpenes); 0 (Organic Chemicals); 0 (Quaternary Ammonium Compounds); 0 (Terpenes); 0 (fabric softeners); 1490-04-6 (Menthol); 9MC3I34447 (limonene); D81QY6I88E (linalool)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE
[do] DOI:10.5650/jos.ess17186


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[PMID]:29279438
[Au] Autor:Ebitani M; Ebitani T
[Ad] Endereço:Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University.
[Ti] Título:[Rotational Isomers of Diphenhydramine].
[So] Source:Yakugaku Zasshi;138(3):417-424, 2018 Mar 01.
[Is] ISSN:1347-5231
[Cp] País de publicação:Japan
[La] Idioma:jpn
[Ab] Resumo: Diphenhydramine (DP), an antihistaminic agent, may become colored and daker or more fluorescent during storage. Herein, we spectroscopically examined the causes of this phenomenon under various DP storage conditions and durations. The infrared vibration-rotation spectrum shows multiple Gauche (G)-type conformers with different intramolecular n→π interaction strengths. The splitting pattern of the dimethylamino group protons in the H-NMR spectrum indicates that DP is mainly in the G-type with a small portion in the Trans (T)-type. The correlation between the red-shifted peak intensity in the UV•VIS absorbance spectrum and the coloring progression indicates a decreased intramolecular n→π interaction of the G-type under elevated temperature during storage. Enhanced fluorescence detected in the Excitation•Fluorescence spectrum demonstrates G-type (quenching) to T-type (fluorescent) conformation conversion, which is due to activated internal rotation of the dimethylamino group under elevated storage temperature and electronic excitation in the phenyl groups under light irradiation during storage. A signal detected in the ESR spectrum corresponds to the G-type charge transfer (CT) structure wherein part of the nonbonding electron pair on the N atom is intramolecularly redistributed to the phenyl groups. The CT structure presents the G-type quenching characteristics, whereas weak CT bonding corresponds to coloring. The results indicate that the quenching G-type is converted to T-type by heat or light to become color faded and bright with enhanced fluorescence and that T-type is reverted to G-type after storage under cool and dark conditions or by vacuum distillation to lose fluorescence.
[Mh] Termos MeSH primário: Difenidramina/química
Estabilidade de Medicamentos
Armazenamento de Medicamentos
Antagonistas dos Receptores Histamínicos/química
[Mh] Termos MeSH secundário: Cor
Espectroscopia de Ressonância de Spin Eletrônica
Fluorescência
Isomerismo
Luz
Espectroscopia de Ressonância Magnética
Conformação Molecular
Rotação
Espectrometria de Fluorescência
Espectrofotometria Infravermelho
Análise Espectral
Temperatura Ambiente
Vibração
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Histamine Antagonists); 8GTS82S83M (Diphenhydramine)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171228
[St] Status:MEDLINE
[do] DOI:10.1248/yakushi.17-00175


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[PMID]:29190078
[Au] Autor:Gonzalez P; Vileno B; Bossak K; El Khoury Y; Hellwig P; Bal W; Hureau C; Faller P
[Ad] Endereço:Institut de Chimie, UMR 7177, CNRS, Université de Strasbourg , 4 rue Blaise Pascal 67000, Strasbourg, France.
[Ti] Título:Cu(II) Binding to the Peptide Ala-His-His, a Chimera of the Canonical Cu(II)-Binding Motifs Xxx-His and Xxx-Zzz-His.
[So] Source:Inorg Chem;56(24):14870-14879, 2017 Dec 18.
[Is] ISSN:1520-510X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Peptides and proteins with the N-terminal motifs NH -Xxx-His and NH -Xxx-Zzz-His form well-established Cu(II) complexes. The canonical peptides are Gly-His-Lys and Asp-Ala-His-Lys (from the wound healing factor and human serum albumin, respectively). Cu(II) is bound to NH -Xxx-His via three nitrogens from the peptide and an external ligand in the equatorial plane (called 3N form here). In contrast, Cu(II) is bound to NH -Xxx-Zzz-His via four nitrogens from the peptide in the equatorial plane (called 4N form here). These two motifs are not mutually exclusive, as the peptides with the sequence NH -Xxx-His-His contain both of them. However, this chimera has never been fully explored. In this work, we use a multispectroscopic approach to analyze the Cu(II) binding to the chimeric peptide Ala-His-His (AHH). AHH is capable of forming the 3N- and 4N-type complexes in a pH dependent manner. The 3N form predominates at pH ∼ 4-6.5 and the 4N form at ∼ pH 6.5-10. NMR experiments showed that at pH 8.5, where Cu(II) is almost exclusively bound in the 4N form, the Cu(II)-exchange between AHH or the amidated AHH-NH is fast, in comparison to the nonchimeric 4N form (AAH). Together, the results show that the chimeric AHH can access both Cu(II) coordination types, that minor changes in the second (or further) coordination sphere can impact considerably the equilibrium between the forms, and that Cu kinetic exchange is fast even when Cu-AHH is mainly in the 4N form.
[Mh] Termos MeSH primário: Complexos de Coordenação/química
Cobre/química
Oligopeptídeos/química
[Mh] Termos MeSH secundário: Sítios de Ligação
Dimerização
Espectroscopia de Ressonância de Spin Eletrônica
Concentração de Íons de Hidrogênio
Cinética
Espectroscopia de Ressonância Magnética
Potenciometria
Conformação Proteica
Proteínas/química
Espectroscopia de Infravermelho com Transformada de Fourier
Análise Espectral Raman
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ala-His-His); 0 (Coordination Complexes); 0 (Oligopeptides); 0 (Proteins); 789U1901C5 (Copper)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180228
[Lr] Data última revisão:
180228
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171201
[St] Status:MEDLINE
[do] DOI:10.1021/acs.inorgchem.7b01996


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[PMID]:29340383
[Au] Autor:Syryamina VN; De Zotti M; Toniolo C; Formaggio F; Dzuba SA
[Ad] Endereço:Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation. dzuba@kinetics.nsc.ru.
[Ti] Título:Alamethicin self-assembling in lipid membranes: concentration dependence from pulsed EPR of spin labels.
[So] Source:Phys Chem Chem Phys;20(5):3592-3601, 2018 Jan 31.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The antimicrobial action of the peptide antibiotic alamethicin (Alm) is commonly related to peptide self-assembling resulting in the formation of voltage-dependent channels in bacterial membranes, which induces ion permeation. To obtain a deeper insight into the mechanism of channel formation, it is useful to know the dependence of self-assembling on peptide concentration. With this aim, we studied Alm F50/5 spin-labeled analogs in a model 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane, for peptide-to-lipid (P/L) ratios varying between 1/1500 and 1/100. Pulsed electron-electron double resonance (PELDOR) spectroscopy reveals that even at the lowest concentration investigated, the Alm molecules assemble into dimers. Moreover, under these conditions, electron spin echo envelope modulation (ESEEM) spectroscopy of D O-hydrated membranes shows an abrupt change from the in-plane to the trans-membrane orientation of the peptide. Therefore, we hypothesize that dimer formation and peptide reorientation are concurrent processes and represent the initial step of peptide self-assembling. By increasing peptide concentration, higher oligomers are formed. A simple kinetic model of equilibrium among monomers, dimers, and pentamers allows for satisfactorily describing the experimental PELDOR data. The inter-label distances in the oligomers obtained from PELDOR experiments become better resolved with increasing P/L ratio, thus suggesting that the supramolecular organization of the higher-order oligomers becomes more defined.
[Mh] Termos MeSH primário: Alameticina/química
Bicamadas Lipídicas/química
[Mh] Termos MeSH secundário: Alameticina/metabolismo
Sequência de Aminoácidos
Dimerização
Espectroscopia de Ressonância de Spin Eletrônica
Cinética
Bicamadas Lipídicas/metabolismo
Fosfatidilcolinas/química
Marcadores de Spin
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Lipid Bilayers); 0 (Phosphatidylcholines); 0 (Spin Labels); 059QF0KO0R (Water); 27061-78-5 (Alamethicin); TE895536Y5 (1-palmitoyl-2-oleoylphosphatidylcholine)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180118
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp07298h


  5 / 28699 MEDLINE  
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[PMID]:29308487
[Au] Autor:Barwinska-Sendra A; Baslé A; Waldron KJ; Un S
[Ad] Endereço:Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK. kevin.waldron@newcastle.ac.uk.
[Ti] Título:A charge polarization model for the metal-specific activity of superoxide dismutases.
[So] Source:Phys Chem Chem Phys;20(4):2363-2372, 2018 Jan 24.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The pathogenicity of Staphylococcus aureus is enhanced by having two superoxide dismutases (SODs): a Mn-specific SOD and another that can use either Mn or Fe. Using 94 GHz electron-nuclear double resonance (ENDOR) and electron double resonance detected (ELDOR)-NMR we show that, despite their different metal-specificities, their structural and electronic similarities extend down to their active-site H- and N-Mn(ii) hyperfine interactions. However these interactions, and hence the positions of these nuclei, are different in the inactive Mn-reconstituted Escherichia coli Fe-specific SOD. Density functional theory modelling attributes this to a different angular position of the E. coli H171 ligand. This likely disrupts the Mn-H171-E170' triad causing a shift in charge and in metal redox potential, leading to the loss of activity. This is supported by the correlated differences in the Mn(ii) zero-field interactions of the three SOD types and suggests that the triad is important for determining metal specific activity.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Manganês/química
Staphylococcus aureus/enzimologia
Superóxido Dismutase/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Sítios de Ligação
Domínio Catalítico
Cristalografia por Raios X
Espectroscopia de Ressonância de Spin Eletrônica
Escherichia coli/metabolismo
Mutagênese Sítio-Dirigida
Ressonância Magnética Nuclear Biomolecular
Oxirredução
Teoria Quântica
Proteínas Recombinantes/biossíntese
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Superóxido Dismutase/química
Superóxido Dismutase/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Recombinant Proteins); 42Z2K6ZL8P (Manganese); EC 1.15.1.1 (Superoxide Dismutase)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180109
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp06829h


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[PMID]:29351320
[Au] Autor:Kumar P; van Son M; Zheng T; Valdink D; Raap J; Kros A; Huber M
[Ad] Endereço:Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands.
[Ti] Título:Coiled-coil formation of the membrane-fusion K/E peptides viewed by electron paramagnetic resonance.
[So] Source:PLoS One;13(1):e0191197, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The interaction of the complementary K (Ac-(KIAALKE)3-GW-NH2) and E (Ac-(EIAALEK)3-GY-NH2) peptides, components of the zipper of an artificial membrane fusion system (Robson Marsden H. et al. Angew Chemie Int Ed. 2009) is investigated by electron paramagnetic resonance (EPR). By frozen solution continuous-wave EPR and double electron-electron resonance (DEER), the distance between spin labels attached to the K- and to the E-peptide is measured. Three constructs of spin-labelled K- and E-peptides are used in five combinations for low temperature investigations. The K/E heterodimers are found to be parallel, in agreement with previous studies. Also, K homodimers in parallel orientation were observed, a finding that was not reported before. Comparison to room-temperature, solution EPR shows that the latter method is less specific to detect this peptide-peptide interaction. Combining frozen solution cw-EPR for short distances (1.8 nm to 2.0 nm) and DEER for longer distances thus proves versatile to detect the zipper interaction in membrane fusion. As the methodology can be applied to membrane samples, the approach presented suggests itself for in-situ studies of the complete membrane fusion process, opening up new avenues for the study of membrane fusion.
[Mh] Termos MeSH primário: Proteínas de Fusão de Membrana/química
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Simulação por Computador
Espectroscopia de Ressonância de Spin Eletrônica
Fusão de Membrana/fisiologia
Proteínas de Fusão de Membrana/fisiologia
Modelos Moleculares
Oligopeptídeos/química
Domínios e Motivos de Interação entre Proteínas
Estrutura Quaternária de Proteína
Estrutura Secundária de Proteína
Marcadores de Spin
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Membrane Fusion Proteins); 0 (Oligopeptides); 0 (Spin Labels)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180221
[Lr] Data última revisão:
180221
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180120
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191197


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[PMID]:28740983
[Au] Autor:Consentius P; Gohlke U; Loll B; Alings C; Heinemann U; Wahl MC; Risse T
[Ad] Endereço:Freie Universität Berlin, Institute of Chemistry and Biochemistry, Takustr. 3, 14195 Berlin, Germany. risse@chemie.fu-berlin.de.
[Ti] Título:Combining EPR spectroscopy and X-ray crystallography to elucidate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals.
[So] Source:Phys Chem Chem Phys;19(31):20723-20734, 2017 Aug 09.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling is used to investigate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals. Within a single crystal, the oriented ensemble of spin bearing moieties results in a strong angle dependence of the EPR spectra. A quantitative description of the EPR spectra requires the determination of the unit cell orientation with respect to the sample tube and the orientation of the spin bearing moieties within the crystal lattice. Angle dependent EPR spectra were analyzed by line shape simulations using the stochastic Liouville equation approach developed by Freed and co-workers and an effective Hamiltonian approach. The gain in spectral information obtained from the EPR spectra of single crystalline samples taken at different frequencies, namely the X-band and Q-band, allows us to discriminate between motional models describing the spectra of isotropic solutions similarly well. In addition, it is shown that the angle dependent single crystal spectra allow us to identify two spin label rotamers with very similar side chain dynamics. These results demonstrate the utility of single crystal EPR spectroscopy in combination with spectral line shape simulation techniques to extract valuable dynamic information not readily available from the analysis of isotropic systems. In addition, it will be shown that the loss of electron density in high resolution diffraction experiments at room temperature does not allow us to conclude that there is significant structural disorder in the system.
[Mh] Termos MeSH primário: Bacteriófago T4/enzimologia
Muramidase/química
Proteínas Virais/química
[Mh] Termos MeSH secundário: Cristalografia por Raios X
Espectroscopia de Ressonância de Spin Eletrônica
Ligações de Hidrogênio
Estrutura Terciária de Proteína
Marcadores de Spin
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Spin Labels); 0 (Viral Proteins); EC 3.2.1.17 (Muramidase)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180212
[Lr] Data última revisão:
180212
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170726
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp03144k


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[PMID]:28668640
[Au] Autor:Mak PJ; Denisov IG
[Ad] Endereço:Department of Chemistry, Saint Louis University, St. Louis, MO, United States. Electronic address: makp@slu.edu.
[Ti] Título:Spectroscopic studies of the cytochrome P450 reaction mechanisms.
[So] Source:Biochim Biophys Acta;1866(1):178-204, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:The cytochrome P450 monooxygenases (P450s) are thiolate heme proteins that can, often under physiological conditions, catalyze many distinct oxidative transformations on a wide variety of molecules, including relatively simple alkanes or fatty acids, as well as more complex compounds such as steroids and exogenous pollutants. They perform such impressive chemistry utilizing a sophisticated catalytic cycle that involves a series of consecutive chemical transformations of heme prosthetic group. Each of these steps provides a unique spectral signature that reflects changes in oxidation or spin states, deformation of the porphyrin ring or alteration of dioxygen moieties. For a long time, the focus of cytochrome P450 research was to understand the underlying reaction mechanism of each enzymatic step, with the biggest challenge being identification and characterization of the powerful oxidizing intermediates. Spectroscopic methods, such as electronic absorption (UV-Vis), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), electron nuclear double resonance (ENDOR), Mössbauer, X-ray absorption (XAS), and resonance Raman (rR), have been useful tools in providing multifaceted and detailed mechanistic insights into the biophysics and biochemistry of these fascinating enzymes. The combination of spectroscopic techniques with novel approaches, such as cryoreduction and Nanodisc technology, allowed for generation, trapping and characterizing long sought transient intermediates, a task that has been difficult to achieve using other methods. Results obtained from the UV-Vis, rR and EPR spectroscopies are the main focus of this review, while the remaining spectroscopic techniques are briefly summarized. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
[Mh] Termos MeSH primário: Sistema Enzimático do Citocromo P-450/química
Heme/química
Ferro/química
Oxigênio/química
[Mh] Termos MeSH secundário: Biocatálise
Espectroscopia de Ressonância de Spin Eletrônica/instrumentação
Espectroscopia de Ressonância de Spin Eletrônica/métodos
Radicais Livres/química
Congelamento
Glicerol/química
Espectroscopia de Ressonância Magnética/instrumentação
Espectroscopia de Ressonância Magnética/métodos
Modelos Moleculares
Oxirredução
Estrutura Secundária de Proteína
Análise Espectral Raman/instrumentação
Análise Espectral Raman/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; REVIEW
[Nm] Nome de substância:
0 (Free Radicals); 42VZT0U6YR (Heme); 9035-51-2 (Cytochrome P-450 Enzyme System); E1UOL152H7 (Iron); PDC6A3C0OX (Glycerol); S88TT14065 (Oxygen)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180208
[Lr] Data última revisão:
180208
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170703
[St] Status:MEDLINE


  9 / 28699 MEDLINE  
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[PMID]:28473297
[Au] Autor:Pochapsky TC; Wong N; Zhuang Y; Futcher J; Pandelia ME; Teitz DR; Colthart AM
[Ad] Endereço:Department of Chemistry, Brandeis University, 415 South St., Waltham, MA 02454-9110, USA. Electronic address: pochapsk@brandeis.edu.
[Ti] Título:NADH reduction of nitroaromatics as a probe for residual ferric form high-spin in a cytochrome P450.
[So] Source:Biochim Biophys Acta;1866(1):126-133, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:The existence of a substrate-sensitive equilibrium between high spin (S=5/2) and low spin (S=1/2) ferric iron is a well-established phenomenon in the cytochrome P450 (CYP) superfamily, although its origins are still a subject of discussion. A series of mutations that strongly perturb the spin state equilibrium in the camphor hydroxylase CYP101A1 were recently described (Colthart et al., Sci. Rep. 6, 22035 (2016)). Wild type CYP101A1 as well as some CYP101A1 mutants are herein shown to be capable of catalyzing the reduction of nitroacetophenones by NADH to the corresponding anilino compounds (nitroreductase or NRase activity). The distinguishing characteristic between those mutants that catalyze the reduction and those that cannot appears to be the extent to which residual high spin form exists in the absence of the native substrate d-camphor, with those showing the largest spin state shifts upon camphor binding also exhibiting NRase activity. Optical and EPR spectroscopy was used to further examine these phenomena. These results suggest that reduction of nitroaromatics may provide a useful probe of residual high spin states in the CYP superfamily. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
[Mh] Termos MeSH primário: Acetofenonas/química
Proteínas de Bactérias/química
Cânfora 5-Mono-Oxigenase/química
Cânfora/química
Compostos Férricos/química
Heme/química
NAD/química
[Mh] Termos MeSH secundário: Acetofenonas/metabolismo
Motivos de Aminoácidos
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Sítios de Ligação
Biocatálise
Cânfora/metabolismo
Cânfora 5-Mono-Oxigenase/genética
Cânfora 5-Mono-Oxigenase/metabolismo
Clonagem Molecular
Espectroscopia de Ressonância de Spin Eletrônica
Escherichia coli/genética
Escherichia coli/metabolismo
Expressão Gênica
Heme/metabolismo
Cinética
Modelos Moleculares
NAD/metabolismo
Oxirredução
Ligação Proteica
Conformação Proteica em alfa-Hélice
Conformação Proteica em Folha beta
Domínios e Motivos de Interação entre Proteínas
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Acetophenones); 0 (Bacterial Proteins); 0 (Ferric Compounds); 0 (Recombinant Proteins); 0U46U6E8UK (NAD); 100-19-6 (4-nitroacetophenone); 42VZT0U6YR (Heme); 76-22-2 (Camphor); EC 1.14.15.1 (Camphor 5-Monooxygenase)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180208
[Lr] Data última revisão:
180208
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170506
[St] Status:MEDLINE


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[PMID]:29361219
[Au] Autor:Agostini A; Palm DM; Paulsen H; Carbonera D
[Ad] Endereço:Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
[Ti] Título:Accessibility of Protein-Bound Chlorophylls Probed by Dynamic Electron Polarization.
[So] Source:J Phys Chem Lett;9(3):672-676, 2018 Feb 01.
[Is] ISSN:1948-7185
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The possibility to probe the accessibility of sites of proteins represents an important point to explore their interactions with specific substrates in solution. The dynamic electron polarization of nitroxide radicals induced by excited triplet states of organic molecules is a phenomenon that is known to occur in aqueous solutions. The interaction within the radical-triplet pair causes a net emissive dynamic electron polarization of the nitroxide radical, that can be detected by means of time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy. We have exploited this effect to prove the accessibility of chlorophylls bound to a protein, namely, the water-soluble chlorophyll protein WSCP. The results have important implications for topological studies in macromolecules.
[Mh] Termos MeSH primário: Clorofila/química
Óxidos de Nitrogênio/química
Proteínas/química
[Mh] Termos MeSH secundário: Espectroscopia de Ressonância de Spin Eletrônica
Transporte de Elétrons
Radicais Livres
Ligação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Free Radicals); 0 (Nitrogen Oxides); 0 (Proteins); 1406-65-1 (Chlorophyll); GFQ4MMS07W (nitroxyl)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180207
[Lr] Data última revisão:
180207
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180124
[St] Status:MEDLINE
[do] DOI:10.1021/acs.jpclett.7b03428



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