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Conformational Ensembles from Experimental Data
and Computer Simulations
Poster Abstracts
142
105-POS
Board 25
Critical Behaviors of Structural Fluctuations in the Native States of Proteins
Wang Wei
1,2,3
, Qian-Yuan Tang
1
, Yang-Yang Zhang
1
, Jun Wang
1,2,3
, Dante Chialvo
4
.
1
Nanjing University, Nanjing, China,
2
National Lab of Solid State Microstructure, Nanjing,
China,
3
Collaborative Innovation Center of Advanced Microstructures, Nanjing, China,
4
Universidad Nacional de San Martin, Buenos Aires, Argentina.
The three-dimensional folded structures of proteins, known as native states, make proteins
capable of performing related biological functions. To achieve such performance, the structure of
the native state of a protein must be susceptible enough to sense the signal and switch to another
structure, but also be stable enough to warrant functional specificity and structural robustness.
This means a coexistence of high susceptibility and stability for the protein around its native
state, which is apparently competing since high susceptibility implies large fluctuations and thus
small stability in general, and vice versa. Does the balance of such competition result in a certain
kind of critical behavior in proteins? Based on protein structural ensembles determined by NMR,
we study the position fluctuations of residues by calculating distance-dependent correlations and
conducting finite-size scaling analysis. The fluctuations exhibit high susceptibility and long-
range correlations up to the protein sizes. The scaling relations between the correlations or
susceptibility and protein sizes resemble those in other physical and biological systems near their
critical points. These results indicate that, at the native states, motions of each residue are felt by
every other one in the protein. We also find that proteins with larger susceptibility are more
frequently observed in nature. Overall, our results suggest that the protein’s native state is
critical.