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How designing brand-new enzymes could change the world

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    Growing up in central Wisconsin,
    I spent a lot of time outside.
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    In the spring, I'd smell
    the heady fragrance of lilacs.
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    In the summer, I loved
    the electric glow of fireflies
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    as they would zip around on muggy nights.
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    In the fall, the bogs were brimming
    with the bright red of cranberries.
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    Even winter had its charms,
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    with the Christmassy bouquet
    emanating from pine trees.
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    For me, nature has always been
    a sense of wonder and inspiration.
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    As I went on to graduate school
    in chemistry, and in later years,
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    I came to better understand
    the natural world in molecular detail.
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    All the things that I just mentioned,
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    from the scents of lilacs and pines
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    to the bright red of cranberries
    and the glow of fireflies,
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    have at least one thing in common.
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    They're manufactured by enzymes.
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    As I said, I grew up in Wisconsin,
    so of course, I like cheese,
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    and the Green Bay Packers.
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    But let's talk about cheese for a minute.
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    For at least the last 7,000 years,
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    humans have extracted a mixture of enzymes
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    from the stomachs of cows
    and sheep and goats,
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    and added it to milk.
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    This causes the milk to curdle --
    it's part of the cheese-making process.
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    The key enzyme in this mixture
    is called chymosin.
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    I want to show you how that works.
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    Right here, I've got two tubes,
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    and I'm going to add chymosin
    to one of these.
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    Just a second here.
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    Now my son Anthony,
    who is eight years old,
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    was very interested in helping me
    figure out a demo for the TED talk,
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    and so we were in the kitchen,
    we were slicing up pineapples,
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    extracting enzymes from red potatoes
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    and doing all kinds of demos
    in the kitchen.
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    And in the end, though,
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    we thought the chymosin demo
    was pretty cool.
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    And so what's happening here
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    is the chymosin
    is swimming around in the milk
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    and it's binding to a protein
    there, called casein.
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    What it does then
    is it clips the casein --
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    it's like a molecular scissors.
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    It's that clipping action
    that causes the milk to curdle.
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    So here we are in the kitchen,
    working on this.
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    OK.
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    So let me give this a quick zip.
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    And then we'll set these to the side
    and let these simmer for a minute.
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    OK.
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    If DNA is the blueprint of life,
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    enzymes are the laborers
    that carry out its instructions.
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    An enzyme is a protein that's a catalyst,
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    it speeds up or accelerates
    a chemical reaction,
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    just as the chymosin over here
    is accelerating the curdling of the milk.
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    But it's not just about cheese.
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    While enzymes do play an important role
    in the foods that we eat,
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    they also are involved in everything
    from the health of an infant
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    to attacking the biggest
    environmental challenges
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    we have today.
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    The basic building blocks of enzymes
    are called amino acids.
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    There are 20 common amino acids
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    and we typically designate them
    with single-letter abbreviations,
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    so it's really an alphabet of amino acids.
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    In an enzyme, these amino acids
    are strung together,
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    like pearls on a necklace.
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    And it's really the identity
    of the amino acids,
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    which letters are in that necklace,
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    and in what order they are,
    what they spell out,
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    that gives an enzyme its unique properties
    and differentiates it from other enzymes.
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    Now, this string of amino acids,
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    this necklace,
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    folds up into a higher-order structure.
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    And if you were to zoom in
    at the molecular level
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    and take a look at chymosin,
    which is the enzyme working over here,
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    you would see it looks like this.
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    It's all these strands and loops
    and helices and twists and turns,
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    and it has to be in just
    this conformation to work properly.
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    Nowadays, we can make enzymes in microbes,
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    and that can be like a bacteria
    or a yeast, for example.
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    And the way we do this
    is we get a piece of DNA
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    that codes for an enzyme
    that we're interested in,
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    we insert that into the microbe,
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    and we let the microbe use
    its own machinery, its own wherewithal,
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    to produce that enzyme for us.
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    So if you wanted chymosin,
    you wouldn't need a calf, nowadays --
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    you could get this from a microbe.
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    And what's even cooler, I think,
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    is we can now dial in
    completely custom DNA sequences
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    to make whatever enzymes we want,
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    stuff that's not out there in nature.
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    And, to me, what's really the fun part
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    is trying to design an enzyme
    for a new application,
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    arranging the atoms just so.
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    The act of taking an enzyme from nature
    and playing with those amino acids,
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    tinkering with those letters,
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    putting some letters in,
    taking some letters out,
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    maybe rearranging them a little bit,
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    is a little bit like finding a book
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    and editing a few chapters
    or changing the ending.
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    In 2018, the Nobel prize in chemistry
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    was given for the development
    of this approach,
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    which is known as directed evolution.
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    Nowadays, we can harness
    the powers of directed evolution
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    to design enzymes for custom purposes,
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    and one of these is designing enzymes
    for doing applications in new areas,
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    like laundry.
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    So just as enzymes in your body
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    can help you to break down
    the food that you eat,
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    enzymes in your laundry detergent
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    can help you to break down
    the stains on your clothes.
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    It turns out that about
    90 percent of the energy
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    that goes into doing the wash
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    is from water heating.
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    And that's for good reason --
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    The warmer water
    helps to get your clothes clean.
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    But what if you were able
    to do the wash in cold water instead?
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    You certainly would save some money,
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    and in addition to that,
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    according to some calculations
    done by Procter and Gamble,
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    if all households in the US
    were to do the laundry in cold water,
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    we would save the emissions
    of 32 metric tons of CO2 each year.
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    That's a lot,
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    that's about the equivalent
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    of the carbon dioxide
    emitted by 6.3 million cars.
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    So, how would we go
    about designing an enzyme
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    to realize these changes?
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    Enzymes didn't evolve
    to clean dirty laundry,
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    much less in cold water.
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    But we can go to nature
    and we can find a starting point.
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    We can find an enzyme
    that has some starting activity,
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    some clay that we can work with.
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    So this is an example of such an enzyme,
    right here on the screen.
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    And we can start playing
    with those amino acids, as I said,
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    putting some letters in,
    taking some letters out,
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    rearranging those.
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    And in doing so, we can generate
    thousands of enzymes.
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    And we can take those enzymes
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    and we can test them
    in little plates like this.
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    So this plate that I'm holding in my hands
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    contains 96 wells,
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    and in each well is a piece of fabric
    with a stain on it.
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    And we can measure
    how well each of these enzymes
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    are able to remove the stains
    from the pieces of fabric,
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    and in that way see how well it's working.
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    And we can do this using robotics,
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    like you'll see
    in just a second on the screen.
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    OK, so we do this and it turns out
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    that some of the enzymes
    are sort of in the ballpark
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    of the starting enzyme.
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    That's nothing to write home about.
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    Some are worse, so we get rid of those.
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    And then some are better.
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    Those improved ones
    become our version 1.0s.
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    Those are the enzymes
    that we want to carry forward
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    and we can repeat this cycle
    again and again.
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    And it's the repetition of this cycle
    that lets us come up with a new enzyme,
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    something that can do what we want.
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    And after several cycles of this,
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    we did come up with something new.
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    So you can go to the supermarket today
    and you can buy a laundry detergent
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    that lets you do the wash in cold water
    because of enzymes like this here.
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    And I want to show you
    how this one works too.
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    So I've got two more tubes here,
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    and these are both milk again.
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    And let me show you,
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    I've got one that I'm going
    to add this enzyme to
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    and one that I'm going
    to add some water to.
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    And that's the control,
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    so nothing should happen in that tube.
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    You might find it curious
    that I'm doing this with milk.
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    But the reason that I'm doing this
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    is because milk
    is just loaded with proteins,
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    and it's very easy to see
    this enzyme working in a protein solution,
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    because it's a master protein chopper,
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    that's its job.
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    So let me get this in here.
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    And you know, as I said,
    it's a master protein chopper
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    and what you can do is you can extrapolate
    what it's doing in this milk
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    to what it would be doing in your laundry.
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    So this is kind of a way to visualize
    what would be happening.
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    OK, so those both went in.
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    And I'm going to give this
    a quick zip as well.
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    OK, so we'll let these sit over here
    with the chymosin sample,
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    so I'm going to come back
    for those toward the end.
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    Well, what's on the horizon
    for enzyme design?
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    Certainly, it will get it faster --
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    there are now approaches
    for evolving enzymes
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    that allow researchers to go
    through far more samples
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    [unclear] like I just showed you.
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    And in addition to tinkering
    with natural enzymes,
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    like we've been talking about,
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    some scientists are now trying to design
    enzymes from scratch,
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    using machine learning,
    an approach from artificial intelligence,
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    to inform their enzyme designs.
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    Still others are adding
    unnatural amino acids to the mix.
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    We talked about
    the 20 natural amino acids,
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    the common amino acids, before --
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    they're adding unnatural amino acids
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    to make enzymes with properties unlike
    those that could be found in nature.
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    That's a pretty neat area.
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    How will designed enzymes affect you
    in years to come?
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    Well, I want to focus on two areas,
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    human health and the environment.
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    Some pharmaceutical companies
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    now have teams that are dedicated
    to designing enzymes
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    to make drugs more efficiently
    and with fewer toxic catalysts.
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    For example, Januvia,
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    which is a medication to treat
    type 2 diabetes,
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    is made partially with enzymes.
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    The number of drugs made with enzymes
    is sure to grow in the future.
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    In another area,
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    there are certain disorders
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    in which a single enzyme
    in a person's body doesn't work properly.
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    An example of this
    is called phenylketonuria,
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    or PKU for short.
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    People with PKU are unable to properly
    metabolize or digest phenylalanine,
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    which is one of the 20 common amino acids
    that we've been talking about.
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    The consequence of ingesting phenylalanine
    for people with PKU
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    is that they are subject
    to permanent intellectual disabilities,
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    so it's a scary thing to have.
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    Now, those of you with kids --
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    do you guys have kids, here,
    which ones have kids?
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    A lot of you.
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    So may be familiar with PKUs,
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    because all infants in the US
    are required to be tested for PKU.
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    I remember when Anthony, my son,
    had his heel pricked to test for it.
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    The big challenge with this
    is what do you eat?
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    Phenylalanine is in so many foods,
    it's incredibly hard to avoid.
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    Now, Anthony has a nut allergy,
    and I thought that was tough,
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    but PKU's on another level of toughness.
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    However, new enzymes
    may soon enable PKU patients
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    to eat whatever they want.
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    Recently, the FDA approved an enzyme
    designed to treat PKU.
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    This is big news for patients,
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    and it's actually very big news
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    for the field of enzyme-replacement
    therapy more generally,
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    because there are other targets out there
    where this would be a good approach.
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    So that was a little bit about health.
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    Now I'm going to move to the environment.
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    When I read about
    the Great Pacific Garbage Patch --
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    by the way, that's, like,
    this huge island of plastic,
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    somewhere between California and Hawaii --
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    and about microplastics
    pretty much everywhere,
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    it's upsetting.
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    Plastics aren't going away anytime soon.
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    But enzymes may help us
    in this area as well.
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    Recently, bacteria producing
    plastic-degrading enzymes were discovered.
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    Efforts are already underway
    to design improved versions
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    of these enzymes.
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    At the same time, there are enzymes
    that have been discovered
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    and that are being optimized
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    to make non-petroleum-derived
    biodegradable plastics.
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    Enzymes may also offer some help
    in capturing greenhouse gases,
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    such as carbon dioxide, methane
    and nitrous oxide.
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    Now, there is no doubt,
    these are major challenges,
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    and none of them are easy.
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    But our ability to harness enzymes
    may help us to tackle these in the future,
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    so I think that's another area
    to be looking forward.
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    So now I'm going to get back
    to the demo --
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    this is the fun part.
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    So we'll start with the chymosin samples.
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    So let me get these over here.
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    And you can see here,
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    this is the one that got the water,
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    so nothing should happen to this milk.
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    This is the one that got the chymosin.
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    So you can see that it totally
    clarified up here.
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    There's all this curdled stuff,
    that's cheese,
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    we just made cheese
    in the last few minutes.
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    So this is that reaction
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    that people have been doing
    for thousands and thousands of years.
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    I'm thinking about doing this one
    at our next Kids to Work Day demo
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    but they can be
    a tough crowd, so we'll see.
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    (Laughter)
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    And then the other one
    I want to look at is this one.
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    So this is the enzyme
    for doing your laundry.
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    And you can see that it's different
    than the one that has the water added.
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    It's kind of clarifying,
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    and that's just what you want
    for an enzyme in your laundry,
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    because you want to be able
    to have an enzyme
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    that can be a protein chowhound,
    just chew them up,
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    because you're going to get
    different protein stains on your clothes,
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    like chocolate milk
    or grass stains, for example,
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    and something like this
    is going to help you get them off.
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    And this is also going to be
    the thing that allows you
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    to do the wash in cold water,
    reduce your carbon footprint
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    and save you some money.
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    Well, we've come a long way,
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    considering the 7,000-year journey
    from enzymes in cheese making
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    to the present day and enzyme design.
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    We're really at a creative crossroads,
  • 12:36 - 12:40
    and with enzymes,
    can edit what nature wrote,
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    or write our stories with amino acids.
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    So next time you're outdoors
    on a muggy night
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    and you see a firefly,
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    I hope you think of enzymes.
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    They're doing amazing things for us today.
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    And by design,
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    they could be doing
    even more amazing things tomorrow.
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    Thank you.
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    (Applause)
Title:
How designing brand-new enzymes could change the world
Speaker:
Adam Garske
Description:

more » « less
Video Language:
English
Team:
closed TED
Project:
TEDTalks
Duration:
13:12

English subtitles

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