5 challenges we could solve by designing new proteins

I'm going to tell you about the most
amazing machines in the world ...

And what we can now do with them.

Proteins,

some of which you see inside a cell here,

carry out essentially all the important
functions in our bodies.

Proteins digest your food,

contract your muscles,

fire your neurons

and power your immune system.

Everything that happens in biology --

almost --

happens because of proteins.

Proteins are linear chains
of building blocks called amino acids.

Nature uses an alphabet
of 20 amino acids,

some of which have names
you may have heard of.

In this picture, for scale,
each bump is an atom.

Chemical forces between the amino acids
cause these long stringy molecules

to fold up into unique,
three-dimensional structures.

The folding process,

while it looks random,

it is in fact very precise.

Each protein folds to its characteristic
shape each time,

and the folding process takes just
a fraction of a second.

And it's the shapes of proteins

which enable them to carry out
their remarkable biological functions.

For example,

hemoglobin has a shape in the lungs
perfectly suited

or binding a molecule of oxygen.

When hemoglobin moves to your muscle,

the shape changes slightly

and the oxygen comes out.

The shapes of proteins,

and hence their remarkable functions,

are completely specified by the sequence
of amino acids in the protein chain.

In this picture, each letter on top
is an amino acide.

Where do these sequences come from?

The genes in your genome specify
the amino acid sequences

of your proteins.

Each gene encodes the amino acid
sequence of a single protein.

The translation between these amino
acid sequences and hte structures

and funcions of proteins

is known as the protein-folding problem.

It's a very hard problem

because there's so many different
shape a protein can adopt.

Because of this complexity,

humans have only been able to harness
the power of proteins

by making very small changes
to the amino acid sequences

of the proteins we found in nature.

This is similar to the process
that our Stone Age ancestors used

to make tools and other implements
from the sticks and stones

that we found in the world around us.