Effects of macromolecular crowding on the collapse of biopolymers.
Experiments show that macromolecular crowding modestly reduces the size of intrinsically disordered proteins even at a volume fraction (ϕ) similar to that in the cytosol, whereas DNA undergoes a coil-to-globule transition at very small ϕ. We show using a combination of scaling arguments and simulations that the polymer size R̅(g)(ϕ) depends on x=R̅(g)(0)/D, where D is the ϕ-dependent distance between the crowders. If x≲O(1), there is only a small decrease in R̅(g)(ϕ) as ϕ increases. When x≫O(1), a cooperative coil-to-globule transition is induced. Our theory quantitatively explains a number of experiments.
Chemical Physics and Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA.
Hongsuk
H
Kang
Materials and Physics Departments, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
Philip A
PA
Pincus
Korea Institute for Advanced Study, Seoul 130-722, Korea.
Changbong
C
Hyeon
Chemical Physics and Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA.
D
D
Thirumalai
D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry*; D008956:Models, Chemical; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*
D046911:Macromolecular Substances; D011506:Proteins; D004247:DNA