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Query: EC:6.2.1.1 (
ACS
)
78,556
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Dopaminergic systems have been described to functionally interact with the neuromodulatory peptide neurotensin. Employing fluorescence detected coimmunoprecipitation and radioligand binding experiments, we herein demonstrate that coexpression of dopamine D(2L) receptor and the neurotensin receptor subtype
NTS
(1) leads to physical interaction and the formation of heteromers in transfected human embryonic kidney 293 cells. In this in vitro system, a trans-inhibitory effect on the agonist binding affinity of D(2) was observed in presence of neurotensin. To correlate between the functional properties of dopaminergic agents and the magnitude of neurotensin-induced modulation of D(2L) binding affinities in cells coexpressing D(2L) and
NTS
(1), a structurally diverse set of dopamine receptor agonists, partial agonists, and antagonists was tested. Ligand specific profiles indicating substantial bias between ligand efficacy and transmodulation were discovered, suggesting a heteromerization-based functional selectivity. In the presence of neurotensin, the novel D(2) agonist FAUC 326 displayed a 34-fold decrease of binding affinity in cells coexpressing D(2L) and
NTS
(1).
ACS
Chem Neurosci 2011 Jun 15
PMID:Cross-receptor interactions between dopamine D2L and neurotensin NTS1 receptors modulate binding affinities of dopaminergics. 2277 74
We have demonstrated that pentafluoro phenoxy boron subphthalocyanine (F5BsubPc) can function as either an electron donor or an electron acceptor layer in a planar heterojunction organic photovolatic (PHJ OPV) cell. F5BsubPc was incorporated into devices with the configurations ITO/MoO3/F5BsubPc/C60/BCP/Al (F5BsubPc used as an electron-donor/hole-transport layer) and ITO/MoO3/Cl-BsubPc/F5BsubPc/BCP/Al (F5BsubPc used as an electron-acceptor/electron-transport layer). Each unoptimized device displayed open-circuit photopotentials (Voc) close to or in excess of 1 V and respectrable power conversion efficiencies. Ultraviolet photoelectron spectroscopy (UPS) was used to characterize the band-edge offset energies at the donor/acceptor junctions. HOMO and LUMO energy level offsets for the F5BsubPc/C60 heterojunction were determined to be ca. 0.6 eV and ca. 0.7 eV, respectively. Such offsets are clearly large enough to produce rectifying J/V responses, efficient exciton dissociation, and photocurrent production at the interface. For the Cl-BsubPc/F5BsubPc heterojunction, the estimated offset energies were found to be ca. 0.1 eV. However, reasonable photovoltaic activity was observed, with photocurrent production coming from both BsubPc species layers. Incident and absorbed photon power conversion efficiencies (IPCE and APCE) showed that photocurrent production qualitatively tracked the absorbance spectra of the donor/acceptor heterojunctions, with some additional photocurrent activity on the low energy side of the absorbance band. We suggest that photocurrent production at higher wavelengths may be a result of charge-transfer species at the donor/acceptor interface.
Cascade
photovoltaics were also fabricated to expand on the understanding of the role of F5BsubPc in such device architectures.
ACS
Appl Mater Interfaces 2014 Feb 12
PMID:Pentafluorophenoxy boron subphthalocyanine (F5BsubPc) as a multifunctional material for organic photovoltaics. 2437 92
Compared with nitroaromatic explosives detection, nitrate esters are far from wide attention possibly because of their shortage of aromatic ring and difficulty in being detected. Three fluorescent chemical probes for trace nitrate ester detection: an intramolecular dimer (P3) of 8-pyrenyl-substituted fluorenes bridged by a 1,6-hexanyl unit as well as its counterparts 2PR-F (P1) and 2PR-Cz (P2) has been synthesized and characterized. Their chemical structures and photophysical and electrochemical properties show that the dimer P3 film has a higher molar extinction coefficient, larger steric hindrance, higher area-to-volume ratio, and matching energy level with nitrate ester explosives, which contributes to higher sensitivity and moderate selectivity for sensing of nitrate ester explosives such as
nitroglycerin
(NG). The fluorescence of the P3 film is rapidly about 90% quenched upon exposure to a saturated vapor of NG for 50 s and almost 100% quenched for 300 s at room temperature due to photoinduced electron transfer between the probe and analyte. In addition, a very sensitive, rapid, simple, and low-cost surface-sensing method by disposable filter-paper-based test strips is demonstrated. The contact-mode approach exhibits a detection limit as low as 0.5 fg/cm(2) for NG. These results reveal that the multiple-pyrenyl-unit-substituted fluorene dimer P3 is suitable for preparing a highly sensitive and efficient thin-film device for detecting nitrate esters.
ACS
Appl Mater Interfaces 2014 Jun 11
PMID:Femtogram level detection of nitrate ester explosives via an 8-pyrenyl-substituted fluorene dimer bridged by a 1,6-hexanyl unit. 2475 51
We report on the mid-infrared nonlinear photothermal spectrum of the neat liquid crystal 4-octyl-4'-cyanobiphenyl (8CB) using a tunable Quantum
Cascade
Laser (QCL). The nonequilibrium steady state characterized by the nonlinear photothermal infrared response undergoes a supercritical bifurcation. The bifurcation, observed in heterodyne two-color pump-probe detection, leads to ultrasharp nonlinear infrared spectra similar to those reported in the visible region. A systematic study of the peak splitting as a function of absorbed infrared power shows the bifurcation has a critical exponent of 0.5. The observation of an apparently universal critical exponent in a nonequilibrium state is explained using an analytical model analogous of mean field theory. Apart from the intrinsic interest for nonequilibrium studies, nonlinear photothermal methods lead to a dramatic narrowing of spectral lines, giving rise to a potential new contrast mechanism for the rapidly emerging new field of mid-infrared microspectroscopy using QCLs.
ACS
Photonics 2014 Aug 20
PMID:Nonlinear Midinfrared Photothermal Spectroscopy Using Zharov Splitting and Quantum Cascade Lasers. 2554 20
Detection of chemical signals is critical for cells in nature as well as in synthetic biology, where they serve as inputs for designer circuits. Important progress has been made in the design of signal processing circuits triggering complex biological behaviors, but the range of small molecules recognized by sensors as inputs is limited. The ability to detect new molecules will increase the number of synthetic biology applications, but direct engineering of tailor-made sensors takes time. Here we describe a way to immediately expand the range of biologically detectable molecules by systematically designing metabolic pathways that transform nondetectable molecules into molecules for which sensors already exist. We leveraged computer-aided design to predict such sensing-enabling metabolic pathways, and we built several new whole-cell biosensors for molecules such as cocaine, parathion, hippuric acid, and
nitroglycerin
.
ACS
Synth Biol 2016 10 21
PMID:Expanding Biosensing Abilities through Computer-Aided Design of Metabolic Pathways. 2702 23
Phase pure nondoped and Ce doped La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
(Al containing La N-phase) samples have been obtained by solid-state reaction synthesis for the first time. 1% Ce-doped La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
phosphor displays a broad excitation band ranging from UV to 410 nm, with a maximum at 355 nm. UV light excitation results in a narrow Ce
3+
5d-4f emission band (fwhm = 68 nm) centered at 418 nm. The emission can be tuned from 417 nm at 0.5% Ce to 450 nm at 50% Ce. A high internal quantum efficiency up to 84% is achieved for a 1% Ce doped sample, which has CIE chromaticity coordinates of x = 0.157 and y = 0.069, close to the NTSC blue standard (x = 0.155; y = 0.070). Compared to La
3
Si
8
O
4
N
11
:Ce phosphor, the quantum efficiency and thermal stability have been enhanced for La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
:Ce phosphor without shifting the emission peak wavelength. La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
:Ce shows less thermal quenching than La
3
Si
8
O
4
N
11
:Ce and no shift or change in the shape of emission spectra with increasing the temperature from 4 to 573 K. These results show that La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
:Ce is more efficient than any other (oxy-)nitride phosphor with an emission in the short wavelength blue region (400-450 nm). A white LED was fabricated using the La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
:5%Ce as a blue phosphor. The high color rendering index (Ra = 93.2, R9 = 91.4, and
R12
= 89.5) obtained shows that the phosphor is a very promising conversion phosphor for white LEDs.
ACS
Appl Mater Interfaces 2017 Jul 12
PMID:Ce-Doped La
3
Si
6.5
Al
1.5
N
9.5
O
5.5
, a Rare Highly Efficient Blue-Emitting Phosphor at Short Wavelength toward High Color Rendering White LED Application. 2858 4
Bacteria and archaea rely on CRISPR (clustered regularly interspaced short palindromic repeats) RNA-guided adaptive immune systems for sequence specific elimination of foreign nucleic acids. In Escherichia coli, short CRISPR-derived RNAs (crRNAs) assemble with Cas (CRISPR-associated) proteins into a 405-kilodalton multisubunit surveillance complex called
Cascade
(CRISPR-associated complex for antiviral defense).
Cascade
binds foreign DNA complementary to the crRNA guide and recruits Cas3, a trans-acting nuclease-helicase required for target degradation. Structural models of
Cascade
have captured static snapshots of the complex in distinct conformational states, but conformational dynamics of the 11-subunit surveillance complex have not been measured. Here, we use hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS) to map conformational dynamics of
Cascade
onto the three-dimensional structure. New insights from structural dynamics are used to make functional predictions about the mechanisms of the R-loop coordination and Cas3 recruitment. We test these predictions in vivo and in vitro. Collectively, we show how mapping conformational dynamics onto static 3D-structures adds an additional dimension to the functional understanding of this biological machine.
ACS
Chem Biol 2018 02 16
PMID:Conformational Dynamics of DNA Binding and Cas3 Recruitment by the CRISPR RNA-Guided Cascade Complex. 2903 97
A fluorescent 2,1,3-benzothiadiazole-containing goniothalamin derivative, BTD-
GTN
(
1
), has been synthesized and successfully tested in bioimaging experiments in live cells. The fluorescent compound proved to be capable of transposing the cell membranes, indicating its subcellular localization. The use of the benzothiadiazole core as the fluorophore revealed the favored localization of the
GTN
analogue
1
in the cytoplasm of live cells, preferentially in the mitochondria, in line with previous results that indicated the loss of mitochondrial transmembrane potential upon treatment with
GTN
. The results described herein highlight the potential of the BTD-
GTN
hybrid structures for future studies regarding the cellular mechanism of action of this family of compounds.
ACS
Omega 2017 Jul 31
PMID:Preferential Mitochondrial Localization of a Goniothalamin Fluorescent Derivative. 3002 3
Atrazine is an herbicide that is widely used in crop production at about 70 million pounds per year in the United States. Its widespread use has led to contamination of groundwater and other aquatic systems. It has resulted in many serious environmental and human health issues. This study focuses on the identification and characterization of a single-stranded DNA (ssDNA) aptamer that binds to atrazine. In this study, a variation of the systematic evolution of ligands by exponential enrichment (SELEX) process was used to identify an aptamer, which binds to atrazine with high affinity and specificity. This SELEX focused on inducing the aptamer's ability to change conformation upon binding to atrazine, and stringent negative target selections. After 12 rounds of in vitro selection, the ssDNA aptamer candidate
R12
.45 was chosen and truncated to obtain a 46-base sequence. The binding affinity, specificity, and structural characteristics of this truncated candidate was investigated by using isothermal titration calorimetry, circular dichroism (CD) analysis, SYBR Green I (SG) fluorescence displacement assays, and gold nanoparticles (AuNPs) colorimetric assays. The truncated
R12
.45 candidate aptamer bound to atrazine with high affinity (
K
d
= 3.7 nM) and displayed low cross-binding activities on structurally related herbicides. In addition, CD analysis data indicated a target induced structural stabilization. Finally, SG assays and AuNPs assays showed nonconventional binding activities between the truncated
R12
.45 aptamer candidate and atrazine, which warrants future studies.
ACS
Omega 2018 Oct 31
PMID:In Vitro Selection and Characterization of a Single-Stranded DNA Aptamer Against the Herbicide Atrazine. 3041 Oct 44
Due to its expression in various malignant tumors, the neurotensin receptor 1 (
NTS
1
R) has been suggested and explored as a target for tumor diagnosis and therapy. Animal model-based investigations of various radiolabeled
NTS
1
R ligands derived from the hexapeptide neurotensin(8-13) (NT(8-13)), e.g.
68
Ga- and
18
F-labeled compounds for PET diagnostics, give rise to optimize such radiotracers for clinical use. As NT(8-13) is rapidly degraded in vivo; structural modifications are required in terms of increased metabolic stability. In this study, the stabilization of the peptide backbone of NT(8-13) against enzymatic degradation was systematically explored by performing an
N
-methyl scan, replacing Ile
12
by
tert
-butylglycine
12
(Tle
12
) and N-terminal acylation.
N
-Methylation of either arginine, Arg
8
, or Arg
9
, combined with the Ile
12
/Tle
12
exchange, proved to be most favorable with respect to
NTS
1
R affinity (
K
i
< 2 nM) and stability in human plasma (
t
1/2
> 48 h), a valuable result regarding the development of radiopharmaceuticals derived from NT(8-13).
ACS
Med Chem Lett 2019 Jun 13
PMID:Modifications at Arg and Ile Give Neurotensin(8-13) Derivatives with High Stability and Retained NTS
1
Receptor Affinity. 3122 55
1
2
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