5 challenges we could solve by designing new proteins David Baker
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,
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
for 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 acid.
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 the structures
and functions of proteins
is known as the protein folding problem.
It’s a very hard problem
because there’s so many different
shapes 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’ve 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.
But humans did not learn to fly
by modifying birds.
(Laughter)
Instead, scientists, inspired by birds,
uncovered the principles of aerodynamics.
Engineers then used those principles
to design custom flying machines.
In a similar way,
we’ve been working for a number of years
to uncover the fundamental
principles of protein folding
and encoding those principles
in the computer program called Rosetta.
We made a breakthrough in recent years.
We can now design completely new proteins
from scratch on the computer.
Once we’ve designed the new protein,
we encode its amino acid sequence
in a synthetic gene.
We have to make a synthetic gene
because since the protein
is completely new,
there’s no gene in any organism on earth
which currently exists that encodes it.
Our advances in understanding
protein folding
and how to design proteins,
coupled with the decreasing cost
of gene synthesis
and the Moore’s law increase
in computing power,
now enable us to design
tens of thousands of new proteins,
with new shapes and new functions,
on the computer,
and encode each one of those
in a synthetic gene.
Once we have those synthetic genes,
we put them into bacteria
to program them to make
these brand-new proteins.
We then extract the proteins
and determine whether they function
as we designed them to
and whether they’re safe.
It’s exciting to be able
to make new proteins,
because despite the diversity in nature,
evolution has only sampled a tiny fraction
of the total number of proteins possible.
I told you that nature uses
an alphabet of 20 amino acids,
and a typical protein is a chain
of about 100 amino acids,
so the total number of possibilities
is 20 times 20 times 20, 100 times,
which is a number on the order
of 10 to the 130th power,
which is enormously more
than the total number of proteins
which have existed
since life on earth began.
And it’s this unimaginably large space
we can now explore
using computational protein design.
Now the proteins that exist on earth
evolved to solve the problems
faced by natural evolution.
For example, replicating the genome.
But we face new challenges today.
We live longer, so new
diseases are important.
We’re heating up and polluting the planet,
so we face a whole host
of ecological challenges.
If we had a million years to wait,
new proteins might evolve
to solve those challenges.
But we don’t have
millions of years to wait.
Instead, with computational
protein design,
we can design new proteins
to address these challenges today.
Our audacious idea is to bring
biology out of the Stone Age
through technological revolution
in protein design.
We’ve already shown
that we can design new proteins
with new shapes and functions.
For example, vaccines work
by stimulating your immune system
to make a strong response
against a pathogen.
To make better vaccines,
we’ve designed protein particles
to which we can fuse
proteins from pathogens,
like this blue protein here,
from the respiratory virus RSV.
To make vaccine candidates
that are literally bristling
with the viral protein,
we find that such vaccine candidates
produce a much stronger
immune response to the virus
than any previous vaccines
that have been tested.
This is important because RSV
is currently one of the leading causes
of infant mortality worldwide.
We’ve also designed new proteins
to break down gluten in your stomach
for celiac disease
and other proteins to stimulate
your immune system to fight cancer.
These advances are the beginning
of the protein design revolution.
We’ve been inspired by a previous
technological revolution:
the digital revolution,
which took place in large part
due to advances in one place,
Bell Laboratories.
Bell Labs was a place with an open,
collaborative environment,
and was able to attract top talent
from around the world.
And this led to a remarkable
string of innovations –
the transistor, the laser,
satellite communication
and the foundations of the internet.
Our goal is to build
the Bell Laboratories of protein design.
We are seeking to attract
talented scientists from around the world
to accelerate the protein
design revolution,
and we’ll be focusing
on five grand challenges.
First, by taking proteins from flu strains
from around the world
and putting them on top
of the designed protein particles
I showed you earlier,
we aim to make a universal flu vaccine,
one shot of which gives a lifetime
of protection against the flu.
The ability to design –
(Applause)
The ability to design
new vaccines on the computer
is important both to protect
against natural flu epidemics
and, in addition, intentional
acts of bioterrorism.
Second, we’re going far beyond
nature’s limited alphabet
of just 20 amino acids
to design new therapeutic candidates
for conditions such as chronic pain,
using an alphabet
of thousands of amino acids.
Third, we’re building
advanced delivery vehicles
to target existing medications
exactly where they need to go in the body.
For example, chemotherapy to a tumor
or gene therapies to the tissue
where gene repair needs to take place.
Fourth, we’re designing smart therapeutics
that can do calculations within the body
and go far beyond current medicines,
which are really blunt instruments.
For example, to target a small
subset of immune cells
responsible for an autoimmune disorder,
and distinguish them from the vast
majority of healthy immune cells.
Finally, inspired by remarkable
biological materials
such as silk, abalone shell,
tooth and others,
we’re designing new
protein-based materials
to address challenges in energy
and ecological issues.
To do all this,
we’re growing our institute.
We seek to attract energetic,
talented and diverse scientists
from around the world,
at all career stages,
to join us.
You can also participate
in the protein design revolution
through our online
folding and design game, “Foldit.”
And through our distributed
computing project, Rosetta@home,
which you can join from your laptop
or your Android smartphone.
Making the world a better place
through protein design is my life’s work.
I’m so excited about
what we can do together.
I hope you’ll join us,
and thank you.
(Applause and cheers)