Model for stretching and unfolding the giant multidomain muscle protein using single-molecule force spectroscopy.
Single-molecule manipulation has allowed the forced unfolding of multidomain proteins. Here we outline 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. 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. Our theory is valid for essentially any molecule that can be unfolded in atomic force microscopy; as a further example, we present force-extension curves for the unfolding of RNA hairpins.
Staple
Douglas B
DB
Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 3J5, Canada.
Payne
Stephen H
SH
Reddin
Andrew L C
AL
Kreuzer
Hans Jürgen
HJ
D064211:Connectin; D007700:Kinetics; D018625:Microscopy, Atomic Force / Q000379:methods; D008956:Models, Chemical; D009124:Muscle Proteins / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D011494:Protein Kinases / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D013816:Thermodynamics
D064211:Connectin; D009124:Muscle Proteins; D011494:Protein Kinases