Women in Science & Leadership Institute present Seminar on:

Protein Folding in the the Cell: Engineering Protein Expression by Understanding Biological Interactions

Guest Speaker: Anne Skaja Robinson of the University of Delaware 

Tuesday, October 20, 2009
Lecture at 4:00 pm
Room 1610 Engineering Hall
Refreshments will be served at 3:45 PM

Our research efforts in bioengineering are aimed at understanding and controlling macromolecular functions and cell behavior to
facilitate biotechnology research, development, and production. In order to improve protein expression, we must understand the
behavior of proteins and other biological macromolecules in isolation, and in the complex environment of the cell. We analyze
proteins’ self-interactions during folding and purification, in order to control structure, function, stability and assembly. We also study
protein-protein interactions and cellular pathways, and use our knowledge to maximize the production of functional proteins. I will
illustrate these approaches to molecular and cellular engineering by describing our studies on pressure refolding of a model protein,
P22 tailspike, and protein expression of a large class of membrane proteins, G-protein coupled receptors.
The first step to controlling off-pathway reactions from folding – aggregation – is to identify critical reactions and intermediates
during the competing processes of folding and misfolding/aggregation. Incorrect association of β-sheets has been identified as a key
step in aggregation for many proteins, including amyloidogenic proteins. We have chosen to use the P22 tailspike protein as a model β
-sheet protein, since it is one of only a handful of proteins for which both folding and aggregation intermediates have been identified. I
will discuss our approach to determining specific aggregation rates and pathways, and to develop novel hydrostatic pressure methods
to dissociate aggregates and form active native protein. In addition, this approach enables us to identify the effect of mutations in the
protein sequences that impact the folding pathway.
Proteins that reside in the cell membrane represent the most difficult challenges for expression and isolation, because they are
extremely hydrophobic. However, they are among the most important of all proteins, as they play key roles in almost every cellular
process. Although membrane proteins represent 30% of all proteins in the genome, due to the difficulties associated with their
production, handling, and structure determination, they represent only 0.3% of all high-resolution protein structures (X-ray and NMR).
Here, I will discuss our studies of integral membrane proteins, in which we try to understand how the membrane proteins form and
insert into the membrane within the cell, as well as characterize their properties once they are isolated in membrane-mimetic
environments. Through this combination of approaches, we can better understand the limitations to large-scale production and
biophysical studies of the G-protein-coupled receptors – the largest known protein superfamily, and the targets of 30-50% of drug
discovery efforts.