Small molecules are difficult to directly detect using commercially available surface plasmon resonance (SPR) instruments. This is because low molecular weight compounds do not have sufficient mass cause a measurable change in refractive index. Refractive index sensitive, however, other properties besides the of analyte. Recently detection substantial conformational changes for immobilized proteins SPR has been reported. However, this property yet exploited ligand binding protein receptors....

Abstract We describe a simple protocol for determining the oxygen consumption of cells in static culture. The is based on noninvasive oxygen‐sensing microplate and mathematical model derived from Fick's Law. applicability confirmed by showing correlation computed rate (OCR) values to actual cell densities ascertained direct counting and/or MTT HL60 U937 cultured suspension. Correlation between OCR these other indications number was quite good, as long cultures were not diffusion‐limited...

We have developed a novel fluorescent Oxygen BioSensor technology platform adaptable to many applications in the area of drug discovery and development, particularly cell-based assays. This biosensor requires no additional reagents or incubations, affords continuous real-time readout dissolved oxygen concentrations. Since level an assay's medium correlates number viability cells medium, this is ideally suited for monitoring cell viability, proliferation, death. The well investigating cells'...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTN-Modified analogs of cocaine: synthesis and inhibition binding to the cocaine receptorPhilip Abraham, J. Bruce Pitner, Anita H. Lewin, John W. Boja, Michael Kuhar, F. Ivy CarrollCite this: Med. Chem. 1992, 35, 1, 141–144Publication Date (Print):January 1992Publication History Published online1 May 2002Published inissue 1 January 1992https://pubs.acs.org/doi/10.1021/jm00079a018https://doi.org/10.1021/jm00079a018research-articleACS...

Environmentally sensitive near-IR (NIR) dyes are useful fluorophores for various biosensor applications when tissue absorption, scattering, and autofluorescence a leading concern. Biosensors operating in the NIR region (generally wavelengths >650 nm) would avoid interference from biological media thereby facilitate relatively free sensing. Squaraine potential candidates to serve as reporter molecules due their spectral properties region, but none is commercially available site-specific...

Periplasmic expression screening is a selection technique used to enrich high-affinity proteins in Escherichia coli. We report using this method rapidly select mutated D-glucose/D-galactose-binding protein (GGBP) having low affinity glucose. Wild-type GGBP has an equilibrium dissociation constant of 0.2 microM and mediates the transport glucose within periplasm E. The undergoes large conformational change on binding and, when labeled with environmentally sensitive fluorophore, can relay...

Chromophores that absorb and emit in the red spectral region (600-700 nm), are water soluble, bear a bioconjugatable tether relatively rare yet would fulfill many applications photochemistry photomedicine. Here, three molecular designs have been developed wherein stable synthetic chlorins - analogues of chlorophylls tailored with PEG groups for use aqueous solution. The differ regard to order installation (pre/post-formation chlorin macrocycle) position groups. Six PEGylated (three free...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudies in biomimetic alkaloid syntheses. 17. Syntheses of iboxyphylline and related alkaloidsMartin E. Kuehne J. Bruce PitnerCite this: Org. Chem. 1989, 54, 19, 4553–4569Publication Date (Print):September 1, 1989Publication History Published online1 May 2002Published inissue 1 September 1989https://pubs.acs.org/doi/10.1021/jo00280a021https://doi.org/10.1021/jo00280a021research-articleACS PublicationsRequest reuse permissionsArticle...

Background: Fluorescent biosensors based on galactose/glucose binding protein (GGBP) and environmentally sensitive derivatives of the phenoxazine dye Nile Red are described. These proposed as sensing platform for a minimally invasive, continuous glucose monitoring system that can be implanted under skin read transdermally using an external fluorometer. Methods: To construct biosensors, thiol-reactive INR IANR were prepared conjugated to GGBP proteins possessing cysteine mutations designed...

The effects of temperature and collisional quenching on fluorescence polarization detection DNA hybridization were studied using measurements intensity anisotropy the dynamic decay these properties. Three different tethers, 3, 6, 12 carbons in length, used to attach fluorescein label 5' end 33-base oligomers. Perrin plots showed that effective rotating volume decreases with increasing tether length approximately doubles upon hybridization. Hybridization increases association between tethered...

Transferred nuclear Overhauser enhancement (TRNOE) experiments have been performed to investigate the bound conformation of trisaccharide repeating unit Streptococcus Group A cell-wall polysaccharide. Thus, conformations propyl 3-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-2-O-(alpha-L-rhamnopyran osyl)- alpha-L-rhamnopyranoside [C(A')B] (1) as a free ligand and when complexed monoclonal antibody Strep 9 were examined. Improved insights about conformational preferences glycosidic linkages...

Site-selective modification of proteins at two separate locations using different reagents is highly desirable for biosensor applications employing fluorescence resonance energy transfer (FRET), but few strategies are available such modification. To address this challenge, sequential selective cysteines in glucose/galactose binding protein (GGBP) was demonstrated a technique we call "ligand protection."In technique, were introduced GGBP and one cysteine rendered inaccessible by the presence...

Synthetic bacteriochlorins absorb in the near-infrared (NIR) region and are versatile analogues of natural bacteriochlorophylls. The utilization these chromophores energy sciences photomedicine requires ability to tailor their physicochemical properties, including incorporation units impart water solubility. Herein, we report synthesis, from two common bacteriochlorin building blocks, five wavelength-tunable, bioconjugatable water-soluble along with non-bioconjugatable benchmarks. Each bears...

Two environmentally sensitive, long-wavelength fluorescent phenoxazine derivatives, INR and IANR, were synthesized with linkers for conjugation to the thiol group of cysteine in binding proteins. The designed based on attachment sites at two different positions phenoxazine, which chosen order study orientation dye respect protein. Conjugation dyes S337C maltose protein (MBP) mutant provided conjugates these that are capable detecting sensitivities. gave a 3-fold (+200%) change fluorescence...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, molecular modeling studies, and muscarinic receptor activity of azaprophen analogsDavid J. Triggle, Yong Who Kwon, Philip Abraham, Bruce Pitner, S. Wayne Mascarella, F. I. CarrollCite this: Med. Chem. 1991, 34, 11, 3164–3171Publication Date (Print):November 1, 1991Publication History Published online1 May 2002Published inissue 1 November...

The fluorescent, oxazole yellow dye YO-Pro-1 iodide (YO) and its homodimer YOYO-1 (YOYO) were studied in a thrombin-binding DNA ligand, or aptamer, (tb-ligand) an oligomer with the same base composition scrambled sequence (s-ligand), both single strands of 15 bases length. Binding constants for dye-ligand complexes, assuming 1:1 stoichiometry, determined to be on order 107M−1 YOYO 105M−1 YO, which are approximately 105 smaller than estimated double-stranded DNA. In ligands, assumes folded...

The original article to which this Erratum refers was published in Biotechnol Bioeng 2004;86:775–787

Abstract Many proteins change their conformation upon ligand binding. For instance, bacterial periplasmic binding (bPBPs), which transport nutrients into the cytoplasm, generally consist of two globular domains connected by strands, forming a hinge. During binding, hinge motion changes from open to closed form. Both forms can be crystallized without ligand, suggesting that energy difference between them is small. We applied Simplicial Neighborhood Analysis Protein Packing (SNAPP) as method...

(±)-6-Methyl-6-azabicyclo[3.2.1]octan-3-one (1c) was prepared in three steps from 6-oxabicyclo[3.2.1]oct-3-en-7-one, and stereoselective reduction of provided (±)-6-methyl-6-azabicyclo[3.2.1]octan-3α-ol (1a); adaptation the sequence first synthesis (+)- (–)-(1a).

Interactions between short single-stranded DNA ligands and fluorescent indicator dyes were used to investigate binding selectivity of the ligands. Conformational differences among four different sequence structure, including two that form a G-quartet do not, confirmed by circular dichroism spectroscopy. Their interactions with YO-pro-1 iodide (YO) YOYO-1 (YOYO) probed using measurements dye absorbance; induced dichroism; fluorescence spectra, anisotropy, lifetime. Equilibrium constants...