Significance of Knotted Structures for Function of Proteins and Nucleic Acids
Poster Session I
10 – POS
Board 10
Mechanical Analysis of Disordered Proteins: Accessing a Third of the Proteome
Gómez-Sicilia, Àngel
1
, Chwastyk, Mateusz
2
, Galea-Prat, Albert
1
, Sikora, Mateusz
2,3,
Carrión-Vázquez, Mariano
1
& Cieplak, Marek
2
.
1
Instituto Cajal /CSIC & IMDEA Nanociencias, Madrid, Spain.
2
Laboratory of Biological
Physics, Institute of Physics, Polish Academy of Sciences,Warsaw, Poland.
3
Institut of Science
and Technology Austria, Klosterneuburg, Austria.
With the advent of single molecule force spectroscopy, many proteins could be examined in
order to uncover the distribution of their mechanical stabilities. However proteins with low or
polymorphic mechanostability could not be unequivocally studied due to the fact that this
technique establishes a hierarchy in which the low-stability structures tend to unfold first, where
they can be mixed with unspecific interactions in the so-called proximal region.
Intrinsically disordered proteins (IDPs) belong to this class of proteins, represent more than one
third of the eukaryotic proteome and many are heavily involved in a variety of diseases. In order
to study the mechanical properties of IDPs, we have developed a mechanical-protection strategy
where the protein under study is inserted inside a more resistant one, which will unfold far from
the proximal region where signal is no longer masked by non-specific noise. Thanks to this
strategy, we have been able to study the rich conformational polymorphism involved in proteins
associated with amyloidogenic neurodegenerative diseases such as Alzheimer's or Huntington's.
As a test for this experimental strategy, we also examined
in silico
different possible
combinations for the protector (host) and protected (guest) molecules using a structurebased
model and compared them to serially connected proteins. Our results show that
the mechanical protection technique works for all the cases and the mechanostability of
the guest is preserved. Also, this method proves that an optimized strategy would be one
in which the single-molecule markers flanking the host molecule have a much lower
mechanostability than the host, so that the unfolding order in the recording is marker,
host, guest and therefore the signal of interest is never mixed with the makers.
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