scholarly journals Exploring the fluorescence quenching interaction of amino acids and protein with natural organic matter by multi-spectroscopic method

2021 ◽  
Author(s):  
Kornravee Saipetch ◽  
Rajendra Khanal ◽  
Masaki Yamazaki ◽  
Qing-Long Fu ◽  
Chihiro Yoshimura ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Hydrogen Bonding ◽  
Fluorescence Quenching ◽  
Natural Organic Matter ◽  
Spectroscopic Method ◽  
Quenching Mechanism ◽  
Potential Binding ◽  
Fluorescence Quenching Mechanism ◽  
Two Peaks

Abstract The main objective of this research was to explore the fluorescence quenching mechanism of humic substance (Suwannee River natural organic matter, (SWNOM)) to amino acids (tryptophan, tyrosine) and protein (bovine serum albumin, (BSA)) by multi-spectroscopic methods. The locations of the peak of tryptophan, tyrosine, and BSA from the Parallel Factor Analysis were at Ex/Em 280/356 nm, 275/302 nm, and 280/344 nm, respectively. For SWNOM, two peaks appeared at Ex/Em of 240/448 nm, and 350/450 nm. Static quenching was the dominant quenching mechanism between BSA and SWNOM, whereas, no quenching was observed between tryptophan or tyrosine and SWNOM. Fourier-transform infrared spectroscopy and thermodynamic calculation demonstrated that hydrogen bonding and van der Waals force are the potential binding forces of BSA-SWNOM complex, as a result of rearrangement in the secondary polypeptide carbonyl hydrogen bonding network of BSA. This rearrangement led to the conformational change in BSA that induced quenching of BSA fluorescence by SWNOM.

pH-related fluorescence quenching mechanism of pterin derivatives and the effects of 6-site substituents

2018 ◽  
Vol 96 (4) ◽  
pp. 404-410
Author(s):  
Lei Liu ◽  
Bingqing Sun
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bonding ◽  
Fluorescence Quenching ◽  
Density Functional ◽  
Relaxation Processes ◽  
Quenching Mechanism ◽  
Functional Theory ◽  
Td Dft ◽  
Fluorescence Quenching Mechanism ◽  
Acidic Conditions

2-Amino-4-hydroxypteridine (pterin) and its derivatives serve as photooxidants and exhibit strong fluorescence. When they interact with hydrogen acceptors such as acetate and phosphate, their fluorescences are significantly quenched in acidic conditions (pH 4.9–5.5) but are retained in basic conditions (pH 10.0–10.5). This pH-related fluorescence quenching mechanism of pterin and its derivatives are fully investigated by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Pterin and its derivatives are demonstrated to show favorable excited-state proton transfer (ESPT) abilities in acidic conditions that induce the experimentally observed fluorescence quenching. In contrast, the ESPT processes are found to be retarded due to the lack of strong hydrogen-bonding interactions in basic environments, which sustain their fluorescence. Interestingly, these ESPT processes are found to show different site specificities depending on the 6-site substituents. The introduction of electron-donating substituent activates the N1 site, making it the preferred ESPT site. By contrast, the introduction of an electron-withdrawing substituent activates the N5 site, making it the favorable ESPT site. The substitutions of different functional groups are found to affect the locations of acidic centers during the excitation and relaxation processes. This further affects the hydrogen-bonding patterns and ultimately brings site specificity to the ESPT process.

A Unified Fluorescence Quenching Mechanism of Tetrazine-Based Dyes: Energy Transfer to a Dark State

2021 ◽  
Author(s):  
Weijie Chi ◽  
Lu Huang ◽  
Chao Wang ◽  
Davin Tan ◽  
Zhaochao Xu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Quenching Mechanism ◽  
Dark State ◽  
Medical Diagnostic ◽  
Fluorogenic Probes ◽  
Fluorescence Quenching Mechanism ◽  
Diagnostic Applications

Tetrazine-based fluorogenic probes are powerful tools for bioimaging, biosensing, and medical diagnostic applications. In these probes, the attachment of a tetrazine moiety generates a non-fluorescent precursor; upon the bio-orthogonal reaction...

Cobalt oxyhydroxide nanoflake based fluorescence sensing platform for label-free detection of DNA

The Analyst ◽  
2016 ◽  
Vol 141 (15) ◽  
pp. 4719-4724 ◽  
Author(s):  
Yaqing Chang ◽  
Zhe Zhang ◽  
Huiqing Liu ◽  
Nan Wang ◽  
Jilin Tang
Keyword(s):  
Fluorescence Quenching ◽  
Label Free ◽  
Quenching Mechanism ◽  
Fluorescence Sensing ◽  
Single Stranded Dna ◽  
Cobalt Oxyhydroxide ◽  
Sensing Platform ◽  
Label Free Detection ◽  
Fluorescence Quenching Mechanism ◽  
Coooh Nanoflakes

In this study, we investigated the interaction of cobalt oxyhydroxide (CoOOH) nanoflakes with DNA and their fluorescence quenching mechanism of a FAM-labeled single-stranded DNA (ssDNA) probe.

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