Unraveling atomic through nanoscale features of underexplored spider silks
Jan
K.
Rainey
Department
of
Biochemistry
&
Molecular
Biology
and
Department
of
Chemistry
Dalhousie
University,
Halifax,
Nova
Scotia
Tuesday,
September
17,
2019
10:00
a.m.
C2-361
(Reading
Room)
Abstract:
Spiders
produce
up
to
seven
protein-based
silks.
These
materials
are
remarkably
strong
and
extensible.
Of
these,
wrapping
silk
is
the
toughest
(i.e.,
it
can
absorb
the
most
energy
prior
to
failure),
with
toughness
per
unit
weight
rivaling
any
known
material.
Pyriform
silk
fibres
are
spun
and
applied
in
a
composite
material
to
attach
webs
to
a
substrate,
with
almost
nothing
known
about
these
fibres.
Exploiting
recombinant
protein
production
in
bacteria,
we
have
been
investigating
the
link
between
the
molecular
architecture,
material
processing,
and
fibre
mechanics
for
each
of
these
silks.
I
will
show
our
evidence
that
each
has
a
modular
behaviour,
with
a
widespread
structural
transition
required
between
the
soluble
and
fibrous
states.
In
each
case,
a
nanoparticle-type
intermediate
may
form
en
route
to
the
ultimate
fibrous
state.
Interestingly,
despite
disparate
amino
acid
composition
and
modular
architecture,
recombinant
pyriform
silk
forms
very
tough
fibres
akin
to
wrapping
silk.
We
are
continuing
to
probe
the
protein
architecture
and
behaviour
at
each
stage
along
the
self-assembly
pathway
for
these
ill-understood
types
of
silk,
with
the
ultimate
goal
of
understanding
the
source
of
the
outstanding
toughness
of
these
materials
and
the
ways
in
which
they
can
be
tweaked
for
a
given
application.