Surface Enhanced Raman Spectroscopy of Membrane Proteins Incorporated into Liposomes

 

Yonglin Liu and A. R. Hight Walker

Optical Technology Division, Physics Laboratory

 

Contraction and relaxation of heart muscle is regulated by cycling calcium ions between the cytoplasm and the sarcoplasmic.  Within the latter, phospholamban (PLB) is an intergral membrane protein that regulates cellular calcium levels by a phosphorylation mechanism.  Abnormalities in the association of protein kinase with PLB have been linked to human heart failure, where a single mutation can be responsible for dilated cardiomyopathy.  The crystal structure of PLB has not been obtained, so any structural information aids in understanding how PLB influences calcium pumps and how many monomer units are necessary for full functionality.  Surface Enhanced Raman Spectroscopy (SERS), a label free technique which probes molecular vibrational modes, can provide selective information concerning molecular structure of biomolecules.  This experiment builds upon our experience in production and characterization of liposomes encapsulated with metal nanoparticles in the aqueous core. The liposomes are spherical, bilayer vesicles which provide a cellular membrane mimetic well suited for this study.  PLB is incorporated in the phospholipid bilayer while gold nanoparticles are inside the nanovial providing enhanced scatter.  In preparation, we have examined commercially available nanostructured surfaces conducive to enhanced Raman scatter for a variety of amino acids.  Furthermore, liposomes have been prepared and characterized via optical microscopy, Raman spectroscopy, dynamic light scattering and Transmission Electron Microscopy. 

 

 

Author Information:

Name:  Yonglin Liu

Mentor’s name: Angela R. Hight Walker

Division: Optical Technology, 844

Laboratory: Physics

Building/Room: 216/B219

Mail Stop: 8443

Telephone #: 301-975- 8568

Fax #:

Email:  yonglin.liu@nist.gov

Sigma Xi: not a member

Category: Physics