A fluorescence resonance energy transfer-derived structure of a quantum dot-protein bioconjugate nanoassembly
A fluorescence resonance energy transfer-derived structure of a quantum dot-protein bioconjugate nanoassembly
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DOI：
10.1073/pnas.0403343101
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发表时间：
2004-06-29
影响因子：
11.1
通讯作者：
Deschamps, JR
中科院分区：
文献类型：
--
作者：
Medintz, IL;Konnert, JH;Deschamps, JR
第一代发光半导体量子点（QD）基杂化无机生物材料和传感器正在开发中。了解生物受体，特别是蛋白质，如何与这些无机纳米材料相互作用至关重要。作为一个模型系统的研究，我们使用罗丹明红标记的工程变种大肠杆菌麦芽糖结合蛋白（MBP）协调的表面555 nm发射的CdSe-ZnS核壳量子点。进行荧光共振能量转移研究以确定从六个独特的MBP-罗丹明红染料受体位置中的每一个到供能QD中心的距离。在一个类似于纳米级的全球定位系统确定的策略中，我们使用从荧光共振能量转移测量，MBP晶体学坐标，和最小二乘法确定的MBP相对于QD表面的取向确定的组装内距离。结果表明，MBP在量子点表面具有择优取向。改进的模型与其他证据一致，这表明蛋白质与QD的配位是通过其C末端五聚组氨酸尾发生的，并且从模型估计的QD大小与QD大小的物理测量结果非常一致。这里详细介绍的方法可能是有用的，在确定其他混合蛋白质纳米颗粒材料中的蛋白质的取向。据我们所知，这是第一个结构模型的混合发光量子点-蛋白质受体组装阐明了使用光谱测量结合晶体学和其他数据。
The first generation of luminescent semiconductor quantum dot (QD)-based hybrid inorganic biomaterials and sensors is now being developed. It is crucial to understand how bioreceptors, especially proteins, interact with these inorganic nanomaterials. As a model system for study, we use Rhodamine red-labeled engineered variants of Escherichia coli maltose-binding protein (MBP) coordinated to the surface of 555-nm emitting CdSe-ZnS core-shell QDs. Fluorescence resonance energy transfer studies were performed to determine the distance from each of six unique MBP-Rhodamine red dye-acceptor locations to the center of the energy-donating QD. In a strategy analogous to a nanoscale global positioning system determination, we use the intraassembly distances determined from the fluorescence resonance energy transfer measurements, the MBP crystallographic coordinates, and a least-squares approach to determine the orientation of the MBP relative to the QD surface. Results indicate that MBP has a preferred orientation on the QD surface. The refined model is in agreement with other evidence, which indicates coordination of the protein to the QD occurs by means of its C-terminal pentahistidine tail, and the size of the QD estimated from the model is in good agreement with physical measurements of QD size. The approach detailed here may be useful in determining the orientation of proteins in other hybrid protein-nanoparticle materials. To our knowledge, this is the first structural model of a hybrid luminescent QD-protein receptor assembly elucidated by using spectroscopic measurements in conjunction with crystallographic and other data.