Cell-Directed Localization and Orientation of a Functional Foreign Transmembrane Protein within a Silica Nanostructure

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• 作者：Eric C. Carnes ; Jason C. Harper ; Carlee E. Ashley ; DeAnna M. Lopez ; Lina M. Brinker ; Juewen Liu ; Seema Singh ; Susan M. Brozik ; C. Jeffrey Brinker
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：October 14, 2009
• 年：2009
• 卷：131
• 期：40
• 页码：14255-14257
• 全文大小：185K
• 年卷期：v.131,no.40(October 14, 2009)
• ISSN：1520-5126

文摘

A simple procedure for introducing functional exogenous membrane-bound proteins to viable cells encapsulated within a lipid templated silica nanostructure is described. In one method, bacteriorhodopsin (bR) was added directly to a Saccharomyces cerevisiae solution along with short zwitterionic diacylphosphatidylcholines (diC₆ PC) and mixed with equal volumes of a sol precursor solution. Alternatively, bR was first incorporated into liposomes (bR-proteoliposomes) and then added to an S. cerevisiae solution with diC₆ PC, and this was followed by mixing with sol precursor solution. Films prepared from bR added directly to diC₆ PC resulted in bR localization near S. cerevisiae cells in a disordered and diffuse fashion, while films prepared from bR-proteoliposomes added to the diC₆ PC/yeast solution resulted in preferential localization of bR near yeast cell surfaces, forming bR-containing multilayer vesicles. Importantly, bR introduced via proteoliposomes was observed to modulate pH gradients developed at the cell surface, demonstrating both retained functionality and preferential orientation. Localization of liposome lipid or bR did not occur around neutrally charged latex beads acting as cell surrogates, demonstrating that living cells actively organize the multilayered lipid during evaporation-induced self-assembly. We expect this simple procedure for introducing functional and oriented membrane-bound proteins to the surface of cells to be general and adaptable to other membrane-bound proteins. This advance may prove useful in fundamental studies of membrane protein function and cell−cell signaling and in imparting non-native characteristics to arbitrary cells.