The research aims of the Columbus laboratory are two fold:

1. To address the challenges in membrane protein structural biology

fig3a_new.pngApproximately 1% of determined structures are membrane proteins structures. One major obstacle to membrane protein structure determination is the selection of a detergent micelle that mimics the native lipid bilayer. The Columbus laboratory uses a multifaceted approach (NMR and EPR spectroscopy, small angle X-ray scattering, and X-ray crystallography) to develop a fundamental understanding of the protein – detergent interaction in order to accelerate the structure determination of membrane proteins. In addition to detergent selection, NMR structure determination of membrane proteins has specific challenges due to molecular size and a lack of structural restraints. Another focus of the lab is to further develop the use of nitroxide spin label paramagnetic relaxation enhancement (PRE) distance restraints for membrane protein structure calculations.

2. To investigate the structural determinants of bacterial pathogen – host interactions mediated by membrane proteins.

Opa mediated phagocytosis (EMBO Journal, 21:560 (2002)).Many obligate bacteria hijack host cellular systems to their advantage. They invade specific cells, can cross the blood brain barrier, avoid cellular degradation pathways, and often control cellular trafficking. Because the obligate bacteria stay intact, most of the hijacking of cellular systems occurs either by bacterial secreted proteins or membrane proteins. The Columbus laboratory aims to understand the molecular basis of bacterial membrane protein – host interactions in order to use specific functions to our advantage – from designing liposomes for drug delivery to engineering liposomes for basic science methodology. In order to engineer or “hijack” these functions, we must understand the molecular determinants of the interactions between host and bacterial membrane receptors that mediate the desired function. To achieve this goal, my laboratory combines a multitude of biophysical and biochemical in vitro methods and collaborates with biologists (such as Alison Criss in the UVA School of Medicine Microbiology Department) in order to gain in vivo insight of in vitro results.