Stretching and unfolding of multidomain biopolymers: a statistical mechanics theory of titin.
Single-molecule manipulation has allowed the forced unfolding of multidomain proteins. Here we develop a theory that not only explains these experiments, but also points out a number of difficulties in their interpretation and makes suggestions for further experiments. Our theory is valid for essentially any molecule that can be unfolded in the AFM: as an example we present force-extension curves for the unfolding of both titin and RNA hairpins. For titin we reproduce force-extension curves, the dependence of break force on pulling speed, and break-force distributions, and also validate two common experimental views: unfolding titin Ig domains can be explained as stepwise increases in contour length, and increasing force peaks in native Ig sequences represent a hierarchy of bond strengths.
Staple
Douglas B
DB
Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS, B3H 3J5 Canada. dstaple@pks.mpg.de
Payne
Stephen H
SH
Reddin
Andrew L C
AL
Kreuzer
Hans Jürgen
HJ
D001696:Biomechanical Phenomena; D064211:Connectin; D055029:Inverted Repeat Sequences; D008958:Models, Molecular; D009124:Muscle Proteins / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D017510:Protein Folding; D011494:Protein Kinases / Q000737:chemistry*; D012313:RNA / Q000737:chemistry*
D064211:Connectin; D009124:Muscle Proteins; D012313:RNA; D011494:Protein Kinases