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LIZ NOLAN: I like
to solve problems.

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And I think I have a fascination
with the natural world.

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And those merge well in
the context of science.

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Not all bacteria are harmful.

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And in fact, if you
consider a person

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on a cell-per-cell basis,
there are more bacterial cells

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in us or on us than are
eukaryotic or human cells.

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Many bacteria help us out, maybe
with the digestion of food.

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But other types of bacteria
have the propensity

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to invade tissues
or produce toxins.

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And so if their populations
get out of check,

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they make us sick.

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Just like humans or any
animal, bacteria need food.

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In my lab, we're particularly
interested in metal ions.

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And you might not think of
metal ions as being food,

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but they are essential
nutrients for all organisms.

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Bacteria seeking to
colonize or survive

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within the host
environment need methods

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to acquire certain metals.

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We respond first by using
our innate immune response.

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MEGAN BROPHY: So
it's kind of gross,

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but you can see some protein.

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And then you have fat
on top where it's shiny.

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I work with a human protein
called calprotectin.

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And it's secreted in response
to bacterial infection.

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And when it encounters
these bacteria,

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it chelates, so it grabs
onto zinc and manganese

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in the environment and
starves the bacteria.

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LIZ NOLAN: So zinc is
an essential nutrient.

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And the general idea is
that calprotectin is somehow

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acting as a sponge.

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In my lab, we over-express
and purify calprotectin

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or [? mutants ?] where
we have systematically

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changed an amino acid we think
is important for calprotectin's

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mechanism and then utilize
this purified protein

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in a suite of studies.

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We can come to conclusions about
where the metal binds and how.

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We can also do experiments
called titrations

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that allow us to determine
how tightly the metal

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binds to a particular site and
also what the selectivity is--

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so does calprotectin
have a preference?

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Does it prefer to bind
zinc over manganese,

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over some other
metal ion or not?

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In high school, I didn't like
my chemistry class very much.

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And that motivated me to
take chemistry first thing

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in college.

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And I loved it.

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I liked that it
was quantitative.

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And I felt it overlapped
well with courses

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I took in biology and geology.

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And when I ultimately
decided on a major,

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I found chemistry the
most appealing because

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of its broad
applicability and ability

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to bring a molecular-level
understanding

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to very complex questions.

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