| Fluorescent protein-based optical biosensor for copper ion quantitation. | |
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MedLine Citation:
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PMID: 19649570 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In the present study, spectroscopic determinations of copper ions using chimeric metal-binding green fluorescent protein (His6GFP) as an active indicator have been explored. Supplementation of copper ions to the GFP solution led to a remarkable decrease of fluorescent intensity corresponding to metal concentrations. For circumstances, rapid declining of fluorescence up to 60% was detected in the presence of 500 microM copper. This is in contrast to those observed in the case of zinc and calcium ions, in which approximately 10-20% of fluorescence was affected. Recovery of its original fluorescence up to 80% was mediated by the addition of ethylenediamine tetraacetic acid. More importantly, in the presence of metal ions, the emission wavelength maximum remains unchanged while reduction of the optical density of the absorption spectrum has been observed. This indicates that the chromophore's ground state was possibly affected by the static quenching process. Results from circular dichroism measurements revealed that the overall patterns of circular dichroism spectra after exposure to copper ions were not significantly different from that of the control, where the majority of sharp positive band around 195-196 nm in combination with a broad negative deflection around 215-216 nm was obtained. Taken together, it can be presumed that copper ions exerted their static quenching on the fluorescence rather than structural or conformational alteration. However, notification has to be made that some peptide rearrangements may also occur in the presence of metal ions. Further studies were conducted to investigate the feasibility of using the His6GFP as a sensing unit for copper ions. The His6GFP was encapsulated in Sol-gel and immobilized onto the optical fiber connected with a fluorescence detecting device. The Sol-gel was doped into the metal solution where the quenching of fluorescence could be monitored in real time. The sensing unit provided a high sensitivity of detection in the range of 0.5 microM to 50 mM with high selectivity for copper ions. All these findings open up a high potential to apply the fluorescent protein-based bioanalytical tool for copper determination in the future. |
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Authors:
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Chartchalerm Isarankura-Na-Ayudhya; Tanawut Tantimongcolwat; Hans-Joachim Galla; Virapong Prachayasittikul |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-08-01 |
Journal Detail:
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Title: Biological trace element research Volume: 134 ISSN: 1559-0720 ISO Abbreviation: Biol Trace Elem Res Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-04-15 Completed Date: 2010-07-19 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7911509 Medline TA: Biol Trace Elem Res Country: United States |
Other Details:
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Languages: eng Pagination: 352-63 Citation Subset: IM |
Affiliation:
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Department of Clinical Microbiology, Mahidol University, Bangkok-Noi, Bangkok, Thailand. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Biosensing Techniques* Cations Circular Dichroism Copper / analysis* Green Fluorescent Proteins / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Cations; 147336-22-9/Green Fluorescent Proteins; 7440-50-8/Copper |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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