A dual-site fluorescent probe for discriminately detecting low and high concentration of hypochlorite in living cells.

Hypochlorite (ClO) is an important bioactive molecule of living system which plays essential roles in many physiological and pathological processes. There is no doubt that the biological roles of ClO depend highly on the concentration of ClO. Unfortunately, the relationship between the concentration of ClO and the biological process is unclear.

Phosphorylation promotes the endonuclease-like activity of human centrin 2.

Centrin is a member of the EF-hand superfamily of calcium-binding proteins, which is involved in the nucleotide excision repair (NER). Reversible phosphorylation of centrin is an important regulatory mechanism and is closely related to many physiological processes. To explore the possible role of centrin in NER, the endonuclease-like activity of human centrin 2 (HsCen2) regulated by phosphorylation in the absence or presence of Tb was investigated by spectroscopy techniques, gel electrophoresis, and molecular docking simulation in 10 mM Hepes, pH 7.

A simple strategy for constructing PET fluorescent probe and its application in hypochlorite detection.

It is great meaningful to develop a fast and efficient method for detecting hypochlorite (ClO) owing to its importance in the immune system. In this work, we proposed a strategy to construct fluorescent probes for ClO based on photoinduced electron transfer (PET) mechanism. According to the strategy, we developed four fluorescent probes named TPA-NO, TPA-2NO, TPB-NO and TPB-2NO, and studied their detecting performances for hypochlorite.

A TICTÂ +Â AIE based fluorescent probe for ultrafast response of hypochlorite in living cells and mouse.

Hypochlorite (HClO/ClO), an important reactive oxygen species (ROS), plays a significant role in the human immune system. Thus, developing a fast and efficient method for detecting ClO is quite necessary. Herein, we designed and synthesized a fluorescent probe TPB-CN based on twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) characteristics.

Tunable NIR AIE-active optical materials for lipid droplet imaging in typical model organisms and photodynamic therapy.

Near infrared (NIR) luminescent materials with aggregation-induced emission (AIE) features have attracted enormous attention in the areas of medical imaging and diagnostic therapeutics because of their low background fluorescence and strong tissue penetration. This study reports a series of easily synthesized AIEgen molecules that feature NIR emission. These molecules have a donor-donor-Ï€-acceptor (D1-D2-Ï€-A) structure with intramolecular charge transfer (ICT) character.

Fluorometric probe for the lipase level: Design, mechanism and biological imaging application.

To realize accurate regulation for fluorescent substrate of lipase, two series compounds (I, II) with similar structure were designed and synthesized. The flexible diphenylmethane was permitted I to go deep into the catalytic site of lipase, while rigid structure of 9H-fluoren makes itself difficult to approach the center. Series I could be effectively hydrolyzed by porcine pancreatic lipase (PPL), and the product emitted fluorescence based on aggregation-induced emission (AIE) mechanism, meanwhile different substituent groups (-Br, -Cl, -Ph, -H) on I induced the tunable hydrolysis rate.

Rational construction of AIEgens with wide color tunability and their specific lipid droplet imaging applications.

Organic light-emitting materials with aggregation-induced emission (AIE) character have experienced a rapid development in imaging, visualization and sensing. In this paper, by installing rotors to an aggregation-caused quenching (ACQ) compound, we constructed an AIE luminogen (AIEgens) system (A2-A4, B1-B3) with wide emission tunability, which covers almost all regions of visible light (400-780 nm). The calculated energy gap of the compounds is consistent with the value of the absorption transition.

Fabricating a fluorescence resonance energy transfer system with AIE molecular for sensitive detection of Cu(II) ions.

The aggregation-induced emission (AIE) luminogens has exhibited strong potential in fabricating the fluorescence resonance energy transfer (FRET) system. In this paper one efficient FRET system was fabricated in aqueous solution based on an AIE molecular (T) and Nile Red (NiR) dyes: T acts as the energy donor and NiR acts as the energy acceptor with a ratio of 250:1. The energy-transfer efficiency from the donor to acceptor is 82.

Calcium and phosphorylation double-regulating caltractin initiating target protein XPC function.

Human centrin 2 (HsCen2) is a member of the EF-hand protein that plays a critical role in the centrosome duplication and separation during cell division. Reversible protein phosphorylation is an important regulatory mechanism for centrin. To obtain insight into the structural basis for the functional effects of phosphorylation, it was verified that the serine residue at position 170 of HsCen2 can be phosphorylated by protein kinase A (PKA) using P NMR spectroscopy.

Visual and fast detection of trace copper ions using biosensor based on FRET.

The development of a simple, rapid and sensitive sensor to detect copper ion is very important for environmental detection. Here, we constructed a fluorescence biosensor based on fluorescence resonance energy transfer (FRET) between copper resistance operon coded protein C (CopC), a copper binding protein, and dansyl chloride (DNS-Cl) to selectively detect copper ion. At alkaline conditions, DNS-Cl was contently attached to CopC forming biosensor of DNS-Cl/CopC, in which fluorescence emission of CopC at 320nm was absorbed by DNS-Cl.

Calcium-induced human centrin 1 self-assembly and double-regulating the binding with peptide R18-Sfi1p.

Centrin is a member of the EF-hand super-family that plays pivotal role in the centrosome duplication and separation. In the present paper, we characterized the properties of metal ions as well as peptide R18-Sfi1p binding to human centrin 1 (HsCen1) by fluorescence spectra and isothermal titration calorimetry (ITC). Four metal ions binding sites on HsCen1 were identified through ITC experiments.

N‑(6‑Aminohexyl)‑5‑chloro‑1‑naphthalenesulfonamide, a centrin antagonist, inhibits Tb/peptides-binding properties.

N‑(6‑Aminohexyl)‑5‑chloro‑1‑naphthalenesulfonamide (W-7), a kind of adjuvant chemotherapy, can bind to calmodulin and inhibit Ca/calmodulin-regulated enzyme activities and cell proliferation. Similar to calmodulin, euplotes octocarinatus centrin (EoCen) belongs to EF-hand superfamily of calcium-binding proteins. It is associated with nucleotide excision repair (NER), cell division cycle and ciliogenesis.

Achieving highly sensitive detection of Cu based on AIE and FRET strategy in aqueous solution.

The aggregation-induced emission (AIE) luminogens are now showing strong potential in mimicking the energy donor of fluorescence resonance energy transfer (FRET) system. Herein, one highly efficient FRET system 1-NiR is successfully fabricated in aqueous solution based on an AIE active compound 1 and fluorescence dyes (Nile red (NiR)). 1 acts as the energy donor and NiR acts as the acceptor in the FRET system with the optimum concentrations ratio [1]/[NiR] = 100.

Study on the interaction between pyridoxal and CopC by multi-spectroscopy and docking methods.

The interaction between pyridoxal hydrochloride (HQ) and apoCopC was investigated using Fourier transform infrared spectroscopy (FTIR), isothermal titration calorimetry (ITC), circular dichroism (CD), fluorescence spectroscopy, three-dimensional (3D) fluorescence spectroscopy, fluorescence lifetime, TNS fluorescence and docking methods. FTIR, CD, TNS fluorescence and fluorescence lifetime experiments suggested that the apoCopC conformation was altered by HQ with an increase in the random coil content and a reduction in the β-sheet content. In addition, the data from fluorescence spectroscopy, 3D fluorescence spectroscopy and molecular docking revealed that the binding site of HQ was located in the hydrophobic area of apoCopC, and a redshift of the HQ fluorescence spectra was observed.

Inhibitory effect of melittin on endonuclease-like activity of centrin.

The xeroderma pigmentosum group C protein (XPC) and centrin2 are the primary initiators of global genome nucleotide excision repair (NER). Centrin, acts as a member of the EF-hand super family of calcium-binding proteins, playing roles in reconstitution of the vitro NER reaction. To understand the possible molecular and structural properties of the multiprotein process, the interactions of Euplotes octocarinatus centrin (EoCen), melittin, and DNA are described.

Assembly and disassembly activity of two AIEE model compounds and its potential application.

Aggregation-induced emission (AIE) has received great attention. In this paper, Cu induced self-assembly and HS induced disassembly of two aggregation-induced emission enhancement (AIEE) compounds were reported in this paper. Two salicylaldehyde azine Schiff base were synthesized and characterized.

Two colorimetric and ratiometric fluorescence probes for hydrogen sulfide based on AIE strategy of α-cyanostilbenes.

Aggregation-induced emission (AIE) active fluorescent probes have attracted great potential in biological sensors. In this paper two cyanostilbene based fluorescence chemoprobe Cya-NO (1) and Cya-N (2) were developed and evaluated for the selective and sensitive detection of hydrogen sulfide (HS). Both of these probes behave aggression-induced emission (AIE) activity which fluoresces in the red region with a large Stokes shift.

Modulation effect of double strand DNA on the self-assembly of N-terminal domain of Euplotes octocarinatus centrin.

Centrin is a member of the EF-hand super family of calcium-binding proteins, which can behave as a part of damage detector initiated the initiation of nucleotide excision repair (NER). Its self-assembly plays a causative role in fiber contraction associated with the cell division cycle and ciliogenesis. To explore the possible role of DNA in the process of centrin self-assembly, the aggregation properties of N-terminal domain of Euplotes octocarinatus centrin (N-EoCen) in the presence of DNA with or without metal ions are investigated.

Modulation of XPC peptide on binding Tb to Euplotes octocarinatus centrin.

Centrins are Ca-binding proteins found throughout eukaryotic organisms. Xeroderma pigmentosum group C protein (XPC), a dominant component of the nuclear excision repair (NER) pathway, is a critical target protein of centrins. A 22-residue peptide (K842-R863) from XPC was used to investigate the effect of metal ions (Ca and Tb) on the peptide binding of Euplotes octocarinatus centrin (EoCen) by isothermal titration calorimetry (ITC) and fluorescence spectroscopy.

Novel bimetallic gold-silver nanoclusters with "Synergy"-enhanced fluorescence for cyanide sensing, cell imaging and temperature sensing.

We herein opened up a facile and green strategy for the fabrication of bright orange-fluorescent gold-silver nanoclusters (AuAgNCs@ew, GSNCs) by a one-pot synthesis at a vital molar ratio of Au/Ag precursors in the egg white protein matrix using microwave-assisted method. The prepared GSNCs exhibited enhanced fluorescence with fluorescent quantum yield of 5.4%, which is dependent on gold and silver synergies.

Electrochemical behavior of hemin binding with human centrin 3.

The electrochemical responses of human centrin 3 (HsCen3) binding with hemin were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using glassy carbon electrodes (GCEs). In CV, the formal potential (E) of hemin with the addition of HsCen3 shifted from -0.51 to -0.

Study on the interaction between curcumin and CopC by spectroscopic and docking methods.

Curcumin is a widely studied polyphenolic compound which has a variety of biological activity as anti-inflammatory and antitumor drugs. Recent research reported that copper chaperone binding with small molecular may relate to the treatment of cancer. In this work, the interaction between curcumin and CopC has been investigated in detail by means of UV-vis absorption, FTIR, CD, fluorescence spectroscopic and molecular docking methods The results showed that the CopC conformation was altered by curcumin with reduction of β-sheet and increase of random coil.

Role of four conserved aspartic acid residues of EF-loops in the metal ion binding and in the self-assembly of ciliate Euplotes octocarinatus centrin.

Ciliate Euplotes octocarinatus centrin (EoCen) is an EF-hand calcium-binding protein closely related to the prototypical calcium sensor protein calmodulin. Four mutants (D37K, D73K, D110K and D146K) were created firstly to elucidate the importance of the first aspartic acid residues (Asp37, Asp73, Asp110 and Asp146) in the beginning of the four EF-loops of EoCen. Aromatic-sensitized Tb fluorescence indicates that the aspartic acid residues are very important for the metal-binding of EoCen, except for Asp73 (in EF-loop II).

Chemical properties and biotoxicity of several chromium picolinate derivatives.

As a man-made additive, chromium picolinate Cr(pic) has become a popular dietary supplement worldwide. In this paper Cr(pic) and its new derivatives Cr(6-CH-pic) (1), [Cr(6-NH-pic)(HO)]NO (2) and Cr(3-NH-pic) (3) were synthesized, and complexes 1 and 2 were characterized by X-ray crystal structure (where pic=2-carboxypyridine). The relationship between the chemical properties and biotoxicity of these complexes was fully discussed: (1) The dynamics stability of chromium picolinate complexes mainly depends on the CrN bonds length.

Acetate ions enhance load and stability of doxorubicin onto PEGylated nanodiamond for selective tumor intracellular controlled release and therapy.

A successful drug delivery device for cancer chemotherapy should ideally be able to load drugs highly, bring the drug preferentially into tumor cells and reduce its distribution in normal tissue to enhance therapeutic efficacy. To this purpose, a novel protocol for DOX-loaded PEGylated nanodiamond (ND-PEG-DOX/NaAc, NPDA) was fabricated using sodium acetate medium. The NPDA nanoparticles exhibited a maximum loading efficiency (99 wt%) with ultra-low drug leakage (7 wt%).