5 challenges we could solve by designing new proteins | David Baker

140,274 views ・ 2019-07-16

TED


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