Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-random coil behavior as a consequence of extensive PPII structure in
  the denatured state   Unfolded proteins may contain native or non-native residual structure, which
has important implications for the thermodynamics and kinetics of folding as
well as for misfolding and aggregation diseases. However, it has been
universally accepted that residual structure should not affect the global size
scaling of the denatured chain, which obeys the statistics of random coil
polymers. Here we use a single-molecule optical technique, fluorescence
correlation spectroscopy, to probe the denatured state of set of repeat
proteins containing an increasing number of identical domains, from two to
twenty. The availability of this set allows us to obtain the scaling law for
the unfolded state of these proteins, which turns out to be unusually compact,
strongly deviating from random-coil statistics. The origin of this unexpected
behavior is traced to the presence of extensive non-native polyproline II
helical structure, which we localize to specific segments of the polypeptide
chain. We show that the experimentally observed effects of PPII on the size
scaling of the denatured state can be well-described by simple polymer models.
Our findings suggest an hitherto unforeseen potential of non-native structure
to induce significant compaction of denatured proteins, affecting significantly
folding pathways and kinetics.

34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin