Reconstructing the free-energy landscape of a mechanically unfolded model protein.
The equilibrium free-energy landscape of an off-lattice model protein as a function of an internal (reaction) coordinate is reconstructed from out-of-equilibrium mechanical unfolding manipulations. This task is accomplished via two independent methods: by employing an extended version of the Jarzynski equality (EJE) and the protein inherent structures (ISs). In a range of temperatures around the "folding transition" we find a good quantitative agreement between the free energies obtained via EJE and IS approaches. This indicates that the two methodologies are consistent and able to reproduce equilibrium properties of the examined system. Moreover, for the studied model the structural transitions induced by pulling can be related to thermodynamical aspects of folding.
Imparato
Alberto
A
Dipartimento di Fisica, INFN Sezione di Torino, CNISM-Sezione di Torino, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy. alberto.imparato@polito.it
Luccioli
Stefano
S
Torcini
Alessandro
A
D000465:Algorithms; D004735:Energy Transfer; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D015233:Models, Statistical; D011487:Protein Conformation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D013816:Thermodynamics
D011506:Proteins