Two-Photon Fluorescence Spectroscopy and Imaging of 4-Dimethylaminonaphthalimide Peptide and Protein Conjugates

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• 作者：Alan M. McLean ; Elke Socher ; Oleg Varnavski ; Travis B. Clark ; Barbara Imperiali ; Theodore Goodson ; III
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：December 19, 2013
• 年：2013
• 卷：117
• 期：50
• 页码：15935-15942
• 全文大小：432K
• 年卷期：v.117,no.50(December 19, 2013)
• ISSN：1520-5207

文摘

We report detailed photophysical studies on the two-photon fluorescence processes of the solvatochromic fluorophore 4-DMN as a conjugate of the calmodulin (CaM) and the associated CaM-binding peptide M13. Strong two-photon fluorescence enhancement has been observed which is associated with calcium binding. It is found that the two-photon absorption cross-section is strongly dependent on the local environment surrounding the 4-DMN fluorophore in the CaM conjugates, providing sensitivity between sites of fluorophore attachment. Utilizing time-resolved measurements, the emission dynamics of 4-DMN under various environmental (solvent) conditions are analyzed. In addition, anisotropy measurements reveal that the 4-DMN鈥揝38C鈥揅aM system has restricted rotation in the calcium-bound calmodulin. To establish the utility for cellular imaging, two-photon fluorescence microscopy studies were also carried out with the 4-DMN-modified M13 peptide in cells. Together, these studies provide strong evidence that 4-DMN is a useful probe in two-photon imaging, with advantageous properties for cellular experiments.