Site-Specific Labeling of Proteins with Near-IR Dyes

Convenient labeling of proteins is important for observing its function under physiological conditions.  In tissues particularly, heptamethine cyanine dyes (Cy-7) are valuable because they absorb in near infrared (NIR) region (750 – 900 nm) where light penetration is maximal.  In this work, we found Cy-7 dyes with a meso-Cl functionality covalently binding to proteins with free Cys residues under physiological conditions (aqueous environments, at near neutral pH, and 37 °C).  It transpired that the meso-Cl of the dye was displaced by free thiols in protein, while nucleophilic side-chains from amino acids like Tyr, Lys, and Ser did not react.  This finding shows a new possibility for convenient and selective labeling of proteins with near-IR fluorescent probes.

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Site-Specific Labeling of Proteins with Near-IR Heptamethine Cyanine Dyes

Molecules ◽

10.3390/molecules23112900 ◽

2018 ◽

Vol 23 (11) ◽

pp. 2900 ◽

Cited By ~ 9

Author(s):

Chen-Ming Lin ◽

Syed Usama ◽

Kevin Burgess

Keyword(s):

Amino Acids ◽

Fluorescent Probes ◽

Near Infrared ◽

Cyanine Dyes ◽

Light Penetration ◽

Selective Labeling ◽

Site Specific ◽

Physiological Conditions ◽

Near Ir ◽

Aqueous Environments

Convenient labeling of proteins is important for observing its function under physiological conditions. In tissues particularly, heptamethine cyanine dyes (Cy-7) are valuable because they absorb in the near-infrared (NIR) region (750–900 nm) where light penetration is maximal. In this work, we found Cy-7 dyes with a meso-Cl functionality covalently binding to proteins with free Cys residues under physiological conditions (aqueous environments, at near neutral pH, and 37 °C). It transpired that the meso-Cl of the dye was displaced by free thiols in protein, while nucleophilic side-chains from amino acids like Tyr, Lys, and Ser did not react. This finding shows a new possibility for convenient and selective labeling of proteins with NIR fluorescent probes.

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Efforts to Quantify Changes in Near-Infrared Spectra Caused by the Influence of Water, pH, Ionic Strength, and Differences in Physical State

Applied Spectroscopy ◽

10.1366/0003702953963788 ◽

1995 ◽

Vol 49 (2) ◽

pp. 181-187 ◽

Cited By ~ 12

Author(s):

James B. Reeves

Keyword(s):

Amino Acids ◽

Ionic Strength ◽

Infrared Spectra ◽

Physical State ◽

Near Infrared ◽

Near Ir ◽

Near Infrared Spectra ◽

Influence Of Water ◽

Water Ph ◽

Crystalline Sugars

The application of near-infrared spectroscopy to high-moisture samples has shown that the accuracy does not match that found for dried materials. The objective of this work was to attempt to quantify the effects of water, pH, ionic strength, and differences in physical state on near-infrared spectra with the use of model compounds. Spectra were compared by regression analysis of second derivatives after spectral subtraction of water. Spectra from 4900 to 4100 cm−1 at a resolution of 4 cm−1 were examined. Regression results showed spectra to be more similar among amorphous sugars and among dissolved sugars than among crystalline sugars. Also, spectra of amorphous sugars were statistically more similar to spectra of dissolved sugars than to spectra of crystalline sugars. While the spectra of one dissolved or amorphous sugar were statistically similar, this was not true for amino acids. Spectra of amorphous amino acids were similar to those of crystalline forms and neither were similar to those of dissolved forms. Spectrally, polymeric carbohydrates appeared very similar to one another when dry and behaved like amino acids when wet. Finally, efforts to directly relate these findings to near-IR spectroscopy calibration problems will require further research.

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Fullerenes, PAHs, Amino Acids and High Energy Astrophysics

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2014.01.0038 ◽

2014 ◽

Vol 1 (1) ◽

pp. 38-41

Author(s):

Susana Iglesias-Groth

Keyword(s):

Amino Acids ◽

Near Infrared ◽

High Energy ◽

Laboratory Work ◽

Near Ir ◽

Diffuse Interstellar Bands ◽

The Galaxy ◽

Spectral Characterisation ◽

Fullerene Formation ◽

Ir Bands

We present theoretical, observational and laboratory work on the spectral properties of fullerenes and hydrogenated fullerenes. Fullerenes in its various forms (individual, endohedral, hydrogenated, etc.) can contribute to the UV bump in the extinction curves measured in many lines of sight of the Galaxy. They can also produce a large number of absorption features in the optical and near infrared which could be associated with diffuse interstellar bands. We summarise recent laboratory work on the spectral characterisation of fullerenes and hydrogenated fullerenes (for a range of temperatures). The recent detection of mid-IR bands of fullerenes in various astrophysical environments (planetary nebulae, reflection nebulae) provide additional evidence for a link between fullerene families and diffuse interstellar bands. We describe recent observational work on near IR bands of C<sub>60</sub><sup>+</sup> in a protoplanetary nebula which support fullerene formation during the post-AGB phase. We also report on the survival of fullerenes to irradiation by high energy particles and gamma photons and laboratory work to explore the chemical reactions that take place when fullerenes are exposed to this radiations in the presence of water, ammonia and other molecules as a potential path to form amino acids.

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Amino acid based gallium-68 chelators capable of radiolabeling at neutral pH

Dalton Transactions ◽

10.1039/c7dt03398b ◽

2017 ◽

Vol 46 (48) ◽

pp. 16973-16982 ◽

Cited By ~ 6

Author(s):

Thomas W. Price ◽

Juan Gallo ◽

Vojtěch Kubíček ◽

Zuzana Böhmová ◽

Timothy J. Prior ◽

...

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Physiological Conditions ◽

Bifunctional Chelators ◽

Neutral Ph ◽

Gallium 68

Herein we show a flexible synthesis for bifunctional chelators based on amino acids that rapidly complex 68Ga under physiological conditions.

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Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200071 ◽

2020 ◽

Vol 92 (2) ◽

pp. 20101

Author(s):

Behnam Kheyraddini Mousavi ◽

Morteza Rezaei Talarposhti ◽

Farshid Karbassian ◽

Arash Kheyraddini Mousavi

Keyword(s):

Silicon Nanowires ◽

Metallic Nanoparticles ◽

Near Infrared ◽

Optical Transition ◽

Electromagnetic Energy ◽

Energy Harvest ◽

Absorption Enhancement ◽

Ir Absorption ◽

Absorption Mechanism ◽

Near Ir

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.

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Faculty Opinions recommendation of Site-specific protein immobilization using unnatural amino acids.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.723878764.793522625 ◽

2016 ◽

Author(s):

Morten Meldal ◽

Sanne Schoffelen

Keyword(s):

Amino Acids ◽

Unnatural Amino Acids ◽

Protein Immobilization ◽

Specific Protein ◽

Site Specific

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Selective Recognition of Amino Acids and Peptides by Small Supramolecular Receptors

Molecules ◽

10.3390/molecules26010106 ◽

2020 ◽

Vol 26 (1) ◽

pp. 106

Author(s):

Joana N. Martins ◽

João Carlos Lima ◽

Nuno Basílio

Keyword(s):

Amino Acids ◽

Selective Recognition ◽

Great Promise ◽

Macrocyclic Compounds ◽

Synthetic Receptors ◽

Small Peptides ◽

Molecular Imprinted Polymers ◽

Polymeric Systems ◽

Physiological Conditions ◽

Level Information

To this day, the recognition and high affinity binding of biomolecules in water by synthetic receptors remains challenging, while the necessity for systems for their sensing, transport and modulation persists. This problematic is prevalent for the recognition of peptides, which not only have key roles in many biochemical pathways, as well as having pharmacological and biotechnological applications, but also frequently serve as models for the study of proteins. Taking inspiration in nature and on the interactions that occur between several receptors and peptide sequences, many researchers have developed and applied a variety of different synthetic receptors, as is the case of macrocyclic compounds, molecular imprinted polymers, organometallic cages, among others, to bind amino acids, small peptides and proteins. In this critical review, we present and discuss selected examples of synthetic receptors for amino acids and peptides, with a greater focus on supramolecular receptors, which show great promise for the selective recognition of these biomolecules in physiological conditions. We decided to focus preferentially on small synthetic receptors (leaving out of this review high molecular weight polymeric systems) for which more detailed and accurate molecular level information regarding the main structural and thermodynamic features of the receptor biomolecule assemblies is available.

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