Department of Mechanical Engineering at The University of Texas at Austin. And we're studying

different ways in which protein mechanics can lead to therapeutic intervention.

We think of a protein as a three-dimensional combination of secondary structures, each

of these secondary structures being represented by the different color struts on this object,

we can understand different ways in which mechanical forces can lead to therapeutic

intervention.

If we take a normal protein, under unstretched conditions, and we consider its interaction

with a small molecule drug.

This small molecule drug may not be able to fit into the protein without any changes in

shape. However, upon the application of mechanical forces, you may get a shape change of the

protein. This shape change may be enough to allow small molecule drugs to interact with

the protein and disrupt its behavior.

Therefore, mechanical properties of proteins may allow us to target drugs at mechanically

regulated or mechanically activated proteins.

If we think about a protein as a three-dimensional construction of individual secondary structures,

each represented by the different color bands on this model, we can understand the value

of trying to describe the mechanical behavior of an individual secondary structure. In such

events, what we study is how the protein secondary structure responds to applied loads, so that

if I pull on this secondary structure, I can understand the ways in which the secondary

structure unfolds.

And one of the questions I always get is "when are cells loaded?" Perhaps a classic example

of this is related to blood flow. We have the example of the heart pumping blood throughout

our body. As the heart pumps, it expands and contracts, expands and contracts. Each one

of those expansions and contractions are stretching the cells inside the heart. Not only are the

cells inside the heart stretching, but also the blood is flowing throughout our body.

Now we can feel this blood flow by checking for our own pulse. When you feel your pulse,

what you're really feeling is the stretching of the underlying artery as the blood flows

past your fingers.

Now if we think about an artery as being lined by cells on the interior, we can understand

that with each one of those pulses, each time the artery stretches, those cells that are

lining that interior are also forced to stretch. They relax back and stretch again, much like

this demonstration of a cell on the inside of an artery.

In this demonstration, we've drawn a cell on the wall of an artery. As the blood pulses

past that cell, we can see an expansion of the cell and a relaxation back to its original

size. This expansion is the stretching of the cell and causes the stretching of the

proteins inside of that cell.