Ultrasensitive and versatile hydrogen peroxide sensing fluorescence quenching.

Reported herein is an ultra-sensitive turn-off fluorescence sensor for hydrogen peroxide based on its reaction with bimane 1. This reaction is highly efficient, resulting in a detection limit of 7.9 pM.

Turn-on Coumarin Precursor: From Hydrazine Sensor to Covalent Inhibition and Fluorescence Detection of Rabbit Muscle Aldolase.

Hydrazine, a highly toxic compound, demands sensitive and selective detection methods. Building upon our previous studies with pre-coumarin OFF-ON sensors for fluoride anions, we extended our strategy to hydrazine sensing by adapting phenol protecting groups (propionate, levulinate, and γ-bromobutanoate) to our pre-coumarin scaffold. These probes reacted with hydrazine, yielding a fluorescent signal with low micromolar limits of detection.

Shining light on fluoride detection: a comprehensive study exploring the potential of coumarin precursors as selective turn-on fluorescent chemosensors.

In this study, we report a fluoride chemosensor based on the use of a non-fluorescent pre-coumarin, compound 1. This compound undergoes selective fluoride-triggered formation of coumarin 2, with a concomitant turn-on fluorescence signal. Although compound 1 exists as a mixture of alkene isomers (2 : 1 in favor of the isomer), only the minor -isomer undergoes cyclization.

Thioxobimanes.

Dioxobimanes, colloquially known as bimanes, are a well-established family of -heterobicyclic compounds that share a characteristic core structure, 1,5-diazabicyclo[3.3.0]octadienedione, bearing two endocyclic carbonyl groups.

Highly Sensitive Water Detection Through Reversible Fluorescence Changes in a -Bimane Based Boronic Acid Derivative.

Reported herein is a fluorometric and colorimetric sensor for the presence of trace amounts of water in organic solvents, using -bimane based boronate ester . This sensor responds to the presence of water with a highly sensitive turn-off fluorescence response, with detection limits as low as 0.018% water (v/v).

A dipodal bimane-ditriazole-diCu(II) complex serves as an ultrasensitive water sensor.

An ultrasensitive fluorescent water sensor based on a dipodal bimane-Cu(II) complex is reported here. This complex, which is non-fluorescent in the absence of water, demonstrates a remarkable turn-on fluorescence in the presence of extremely low (0.000786% v/v) concentrations of water, highly selective water-induced displacement of copper and restoration of the innate bimane fluorescence.

Highly sensitive detection of cobalt through fluorescence changes in β-cyclodextrin-bimane complexes.

A supramolecular complex of syn-(methyl,methyl)bimane (1) and β-cyclodextrin demonstrates a sensitive (limit of detection = 0.60 nM) and selective fluorescence turn-off response in the presence of cobalt in aqueous media, with calibration curves enabling quantitation in solution and using filter papers on which bimane and cyclodextrin were adsorbed. 1H NMR spectroscopy provides insight into interactions underlying the sensor performance.

Expedient synthesis and anticancer evaluation of dual-action 9-anilinoacridine methyl triazene chimeras.

The efficient synthesis of molecular hybrids including a DNA-intercalating 9-anilinoacridine (9-AnA) core and a methyl triazene DNA-methylating moiety is described. Nucleophilic aromatic substitution (S Ar) and electrophilic aromatic substitution (EAS) reactions using readily accessible starting materials provide a quick entry to novel bifunctional anticancer molecules. The chimeras were evaluated for their anticancer activity.

A two-step strategy to visually identify molecularly imprinted polymers for tagged proteins.

A practical and relatively simple method to identify molecularly imprinted polymers capable of binding proteins via the molecular tagging (epitope-like) approach has been developed. In our two-step method, we first challenge a previously obtained anti-tag molecularly imprinted polymer with a small molecule including the said tag of choice (a biotin derivative as shown here or other) connected to a linker bound to a second biotin moiety. An avidin molecule partially decorated with fluorescent labels is then allowed to bind the available biotin derivative associated with the polymer matrix.

syn-Bimane as a chelating O-donor ligand for palladium(ii).

A cationic Pd(ii) complex containing syn-(Me,Me)bimane as a ligand was prepared and fully characterized. This complex represents the first well-defined case of a bimane scaffold coordinated to a metal center. The strongly-fluorescent syn-bimane chelates the Pd(ii) center via its carbonyl oxygen atoms, affording a non-fluorescent complex.

Biolabile peptidyl delivery systems toward sequential drug release.

Compact carriers for peptidyl delivery systems (PDSs) loaded with various drugs were synthesized using a simple and convenient solid phase organic synthesis strategy, including semi-orthogonal functional group protection schemes. Each attachment point of the compact carrier can thus be bound to an anticancer agent through a biodegradable covalent link. Chemo- and biostability experiments of a model peptidyl platform loaded with three different drugs revealed pH and liver homogenate (metabolic) dependent sequential release behavior.

α-Aminoisobutyric Acid Leads a Fluorescent syn-bimane LASER Probe Across the Blood-brain Barrier.

Penetration of the blood brain barrier (BBB) by appropriate fluorescent probes remains a challenge in optical imaging and diagnostics. We designed, synthesized and observed the in vivo BBB penetration of a LASER syn-bimane probe. Results demonstrate that the Aib transporter unit in our probe may lead a fluorescent bimanyl moiety across the BBB.

Automated docking with protein flexibility in the design of femtomolar "click chemistry" inhibitors of acetylcholinesterase.

The use of computer-aided structure-based drug design prior to synthesis has proven to be generally valuable in suggesting improved binding analogues of existing ligands. Here we describe the application of the program AutoDock to the design of a focused library that was used in the "click chemistry in-situ" generation of the most potent noncovalent inhibitor of the native enzyme acetylcholinesterase (AChE) yet developed (K(d) = ~100 fM). AutoDock version 3.

Mutants of 4-oxalocrotonate tautomerase catalyze the decarboxylation of oxaloacetate through an imine mechanism.

A designed single amino acid substitution can alter the catalytic activity and mechanism of 4-oxalocrotonate tautomerase (4-OT). While the wild-type enzyme catalyzes only the tautomerization of oxalocrotonate, the Pro1Ala mutant (P1A) catalyzes two reactions--the original tautomerization reaction and the decarboxylation of oxaloacetate. Although the N-terminal amine group of P1A is involved in both reactions, our results support a nucleophilic mechanism for the decarboxylase activity, in contrast to the general acid/base mechanism that has been previously established for the tautomerase activity.

Model of the alphaLbeta2 integrin I-domain/ICAM-1 DI interface suggests that subtle changes in loop orientation determine ligand specificity.

The interaction of the alphaLbeta2 integrin with its cellular ligand the intercellular adhesion molecule-1 (ICAM-1) is critical for the tight binding interaction between most leukocytes and the vascular endothelium before transendothelial migration to the sites of inflammation. In this article we have modeled the alphaL subunit I-domain in its active form, which was computationally docked with the D1 domain of the ICAM-1 to probe potential protein-protein interactions. The experimentally observed key interaction between the carboxylate of Glu 34 in the ICAM-1 D1 domain and the metal ion-dependent adhesion site (MIDAS) in the open alphaL I-domain was consistently reproduced by our calculations.