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RISS 인기검색어
- 검색키워드
- 저자 : ( Yuvaraj Ravikumar ) (검색결과 4 건)
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A New-Generation Fluorescent-Based Metal Sensor-iLOV Protein
( Yuvaraj Ravikumar ),( Saravanan Prabhu Nadarajan ),( Chong Soon Lee ),( Jin Kyu Rhee ),( Hyung Don Yun ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.4
The iLOV protein belongs to a family of blue-light photoreceptor proteins containing a lightoxygen- voltage sensing domain with a noncovalently bound flavin mononucleotide (FMN) as its chromophore. Owing to advantages such as its small size, oxygen-independent nature, and pH stability, iLOV is an ideal candidate over other reporter fluorescent proteins such as GFP and DsRed. Here, for the first time, we describe the feasibility of applying LOV domain-based fluorescent iLOV as a metal sensor by measuring the fluorescence quenching of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the inherent copper sensing property of the iLOV protein and identified the possible amino acids responsible for metal binding. The fluorescence quenching upon exposure to Cu2+ was highly sensitive and exhibited reversibility upon the addition of the metal chelator EDTA. The copper binding constant was found to be 4.72 ± 0.84 μM. In addition, Cu2+-bound iLOV showed high fluorescence quenching at near physiological pH. Further computational analysis yielded a better insight into understanding the possible amino acids responsible for Cu2+ binding with the iLOV protein.
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( Yuvaraj Ravikumar ),( Saravanan Prabhu Nadarajan ),( Chong Soon Lee ),( Seunho Jung ),( Dong Ho Bae ),( Hyungdon Yun ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.3
Bacterial light-oxygen-voltage-sensing photoreceptor-derived flavin mononucleotide (FMN)- based fluorescent proteins act as a promising distinct class of fluorescent proteins utilized for various biomedical and biotechnological applications. The key property of its independency towards oxygen for its chromophore maturation has greatly helped this protein to outperform the other fluorescent proteins such as GFP and DsRed for anaerobic applications. Here, we describe the feasibility of FMN-containing fluorescent protein FbFP as a metal-sensing probe by measuring the fluorescence emission changes of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the mercury-sensing ability of FbFP protein and the possible amino acids responsible for metal binding. A ratiometric approach was employed here in order to exploit the fluorescence changes observed at two different emission maxima with respect to Hg(2+) at micromolar concentration. The engineered variant FbFPC56I showed high sensitivity towards Hg(2+) and followed a good linear relationship from 0.1 to 3 μM of Hg(2+). Thus, further engineering with a rational approach would enable the FbFP to be developed as a novel and highly selective and sensitive biosensor for other toxic heavy metal ions as well.
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Min, Byung-Hwa,Ravikumar, Yuvaraj,Lee, Do-Hee,Choi, Kwang Seek,Kim, Bo-Mi,Rhee, Jae-Sung Elsevier 2018 Environmental pollution Vol.232 No.-
<P><B>Abstract</B></P> <P>Microcystins (MCs) are naturally occurring algal toxins in the aquatic environment and pose a serious threat to the ecosystem. In general, aquatic populations are structured by organisms of different ages, with varying degrees of biochemical and physiological responses. In this study, juvenile and adult marine mysids (<I>Neomysis awatschensis</I>) were exposed to MC-Leucine Arginine (MC-LR) (0.1, 1, and 10 μg L<SUP>−1</SUP>) for 7 days, and the bioconcentration dynamics and responses of antioxidant defense system were measured during the exposure and additional depuration periods (7 days). MC-LR bioconcentrated in a dose-dependent manner, from a threshold concentration of 1 μg L<SUP>−1</SUP> in both stages, and the levels reduced gradually during the depuration phase. Bioconcentration patterns of MC-LR were highly age-specific, as juvenile mysids showed peaks during the exposure period, whereas adults exhibited a peak on the first day of depuration. After exposure to 10 μg L<SUP>−1</SUP> concentration, elevated levels of malondialdehyde (MDA) and glutathione (GSH) were observed during the late (days 5 and 7) exposure and early (days 1 and 3) depuration periods in juvenile mysids, while adult mysids showed a peak on day 7 of the exposure period. Age-specific responses were also observed in the enzymatic activities of glutathione <I>S</I>-transferase (GST), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR). Juvenile mysids showed a significant elevation in all enzymatic activities during the exposure and/or depuration phase upon exposure to 10 μg L<SUP>−1</SUP> MC-LR, but only CAT and SOD enzymes showed significant changes during the exposure and/or depuration periods in adults. Overall, our results indicate the bioconcentration potential of MC-LR and its threshold in the marine mysid, in addition to age-specific MC-LR dynamics and subsequent biochemical responses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MC-LR was dose-dependently bioconcentrated from 1 μg L<SUP>−1</SUP> threshold in the marine mysid. </LI> <LI> Biocencentrated MC-LR concentrations decreased during the depuration phase. </LI> <LI> MC-LR induced similar dynamics of GSH and MDA at 10 μg L<SUP>−1</SUP> in juvenile and adult mysid. </LI> <LI> Antioxidant enzyme activities showed age-specific dynamics in the marine mysid. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Engineering lead-sensing GFP through rational designing
Nadarajan, Saravanan Prabhu,Ravikumar, Yuvaraj,Deepankumar, Kanagavel,Lee, Chong-Soon,Yun, Hyungdon The Royal Society of Chemistry 2014 Chemical communications Vol.50 No.100
<P>Lead is one of the most hazardous metals ubiquitous in the environment, causing serious health hazards to organisms. Recently, fluorescent proteins such as GFP and Dsred were utilized for the development of reagent-less rapid metal sensors. Here, we demonstrate the development of a lead-sensing GFP that is highly sensitive to lead at micro molar concentrations.</P> <P>Graphic Abstract</P><P>A lead biosensor (PbGFP) was developed by engineering lead binding site near the chromophore of green fluorescent protein. The specific binding of lead to chromophore of PbGFP resulted in turn-off mechanism. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cc07163h'> </P>
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