生物谷報道：如果你已經厭倦了發(fā)燒時將體溫計含在嘴來量體溫,，那么你或許可以選擇用一種在細胞內部的“芯片實驗室”,，即一種閃動的蛋白質可能成為理想的體溫計。
來源于生物發(fā)光水母Aequorea victoria的綠色熒光蛋白（GFP）在著少特定波長的光時會發(fā)出綠色熒光,。但 是,，這種怪異的光不是持續(xù)性的。在液體中,，這種蛋白質在喪失質子和得回質子時，出現(xiàn)光的明暗閃爍,。
現(xiàn)在,，來自加拿大McMaster大學的Cécile Fradin和同事發(fā)現(xiàn)，閃爍的頻率在熱的環(huán)境條件下變緩慢,，而在溫度降低時則加速,。這個特征使它能夠成為一種縮微型的體溫計。
研究人員用一束光照射含有這種蛋白質的液體,，然后根據熒光的閃爍頻率來確定溫度,。他們發(fā)現(xiàn)在10到50攝氏度之間，這種蛋白質的閃爍頻率能夠準確測量所處的液體環(huán)境的溫度,。
綠色螢光蛋白(green fluorescent protein),，簡稱GFP，最早是由下村脩等人于1962年在一種學名Aequorea victoria的水母中發(fā)現(xiàn),。其基因所產生的蛋白質,，在藍色波長范圍的光線激發(fā)下，會發(fā)出綠色熒光,。這個發(fā)光 的過程中還需要冷光蛋白質Aequorin的幫助,，且這個冷光蛋白質與鈣離子(Ca+2)可產生交互作用。
由水母Aequorea victoria中發(fā)現(xiàn)的野生型綠色熒光蛋白,，395nm和475nm分別是最大和次大的激發(fā)波長,，它的發(fā)射波長的峰點是在509nm，在可見光綠光的范圍下是較弱的位置,。由海腎(sea pansy)所得的綠色熒光蛋白,，僅有在498nm有一個較高的激發(fā)峰點。
在細胞生物學與分子生物學領域中,，綠色熒光蛋白基因常被用作為一個報導基因(reporter gene),。一些經修飾過的型式可作為生物探針，綠色熒光蛋白基因也可以克隆到脊椎動物中,。
原始出處:
J. Am. Chem. Soc., 129 (34), 10302 -10303, 2007. 10.1021/ja0715905 S0002-7863(07)01590-9
Web Release Date: August 8, 2007 Copyright © 2007 American Chemical Society
A Molecular Thermometer Based on Fluorescent Protein Blinking
Felix H. C. Wong, Daniel S. Banks, Asmahan Abu-Arish, and Cécile Fradin*
Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1, and Department of Biochemistry and Biomedical Science, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada, L8N 3Z5
[email protected]
Received March 6, 2007
Abstract:
With the present trend toward a miniaturization of chemical systems comes the need for a precise characterization of physicochemical parameters in very small fluid volumes. We describe here an original approach for small-scale temperature measurements based on the detection of fluorescent protein blinking. We observed that the characteristic time associated with the reversible protonation reaction responsible for the blinking of the enhanced green fluorescent protein is strongly temperature dependent at low pH. The blinking characteristic time can easily be detected by fluorescence correlation spectroscopy, and therefore provides the means for noninvasive, spatially resolved, absolute temperature measurements. We applied this approach to the quantification of laser-heating effects in thin liquid samples. As expected, we observed a linear dependence between the temperature increase at the laser focus and both the laser power and the sample extinction coefficient. In addition, we were able to measure the laser induced temperature increase at the glass/liquid interface, a value difficult to predict and hard to access experimentally, demonstrating the usefulness of our approach to study surface effects in microfluidic chips. The use of GFP derivatives as genetically encoded molecular thermometers should have direct applications for both microfluidics and single-cell calorimetry.
