(703b) Targeted Binding of Nanolipoprotein Particles to Phase Separated Lipid Domains

Targeted binding of functional proteins and/or biomolecules to supported lipid bilayers has a variety of applications, including development of nano-array technologies and biosensors. Use of Integral Membrane Proteins (IMPs) in such systems is difficult, as incorporation into planar bilayers is not straightforward and can result in protein inactivation. We intend to overcome this limitation by use of Nanolipoprotein Particles (NLPs), which are able to solubilize IMPs. NLPs are discoidal patches of lipid bilayer that have their hydrophobic faces covered by amphiphilic scaffold proteins. The scaffold proteins can bear polyhistadine tags, which are capable of chelating to Cu²⁺ metal ions. Phase specific, Iminodiacetic acid functionalized lipids are also capable of chelating Cu²⁺, providing a mechanism for targeted binding of NLPs. We investigate this binding via fluorescence microscopy and characterize interaction on supported bilayers and giant unilamellar vesicles (GUVs). The thermodynamics (enthalpy of lipid mixing and steric pressure of protein crowding) and morphology of binding are also examined.