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Abstract

The coupling of a DNA-binding protein to self-organized lipid monolayers is examined at the air-water interface by means of film balance techniques and epifluorescence microscopy, We used two recombinant species of the heat shock factor HSF24 which differ only in a carboxy-terminal histidine tag that interacts specifically with the nickel-chelating head group of a synthetic chelator lipid, As key function, HSF24 binds to DNA that contains heat-shock responsible promoter elements. In solution, DNA-protein complex formation is demonstrated for the wild type and fusion protein. Substantial questions of these studies are whether protein function is affected after adsorption to lipid layers and whether a specific docking via histidine tag to the chelator lipid leads to functional immobilization. Using lipid mixtures that allow a lateral organization of chelator lipids within the lipid film, specific binding and unspecific adsorption can be distinguished by pattern formation of DNA-protein complexes. At the lipid interface, functional DNA-protein complexes are only detected, when the histidine-tagged protein was immobilized specifically to a chelator lipid containing monolayer, These results demonstrate that the immobilization of histidine-tag,oed biomolecules to membranes via chelator lipids is a promising approach to achieve a highly defined deposition of these molecules at an interface maintaining their function. [References: 38]