title: An energetic model for macromolecules unfolding in stretching experiments.
abstract: We propose a simple approach, based on the minimization of the total (entropic plus unfolding) energy of a two-state system, to describe the unfolding of multi-domain macromolecules (proteins, silks, polysaccharides, nanopolymers). The model is fully analytical and enlightens the role of the different energetic components regulating the unfolding evolution. As an explicit example, we compare the analytical results with a titin atomic force microscopy stretch-induced unfolding experiment showing the ability of the model to quantitatively reproduce the experimental behaviour. In the thermodynamic limit, the sawtooth force-elongation unfolding curve degenerates to a constant force unfolding plateau.
authors.affiliation: Dipartimento di Scienze dell' Ingegneria Civile e Architettura, Politecnico di Bari, Bari, Italy.
authors.forename: D
authors.initials: D
authors.lastname: De Tommasi
authors.forename: N
authors.initials: N
authors.lastname: Millardi
authors.forename: G
authors.initials: G
authors.lastname: Puglisi
authors.forename: G
authors.initials: G
authors.lastname: Saccomandi
mesh_terms: D008956:Models, Chemical; D008968:Molecular Conformation; D011134:Polysaccharides / Q000737:chemistry*; D047011:Silk / Q000737:chemistry*; D013314:Stress, Mechanical; D013816:Thermodynamics
chemical_list: D011134:Polysaccharides; D047011:Silk
keywords: biopolymers; macromolecule mechanics; macromolecules unfolding; protein stability; titin
references.citation: Proc Natl Acad Sci U S A. 2006 Apr 4;103(14):5279-84
references.pmid: 16567628
references.citation: Annu Rev Biophys Biomol Struct. 2001;30:361-96
references.pmid: 11340064
references.citation: J Phys Condens Matter. 2006 Aug 16;18(32):R531-83
references.pmid: 21690856
references.citation: Nature. 2010 May 6;465(7294):69-73
references.pmid: 20445626
references.citation: Biophys J. 2010 May 19;98(9):1941-8
references.pmid: 20441758
references.citation: J Mol Biol. 2003 Jul 18;330(4):867-77
references.pmid: 12850153
references.citation: Biophys J. 2009 Mar 18;96(6):2160-7
references.pmid: 19289042
references.citation: Science. 1997 May 16;276(5315):1109-12
references.pmid: 9148804
references.citation: Biophys J. 2007 Mar 1;92(5):L39-41
references.pmid: 17172299
references.citation: Phys Rev Lett. 2000 Mar 6;84(10):2160-3
references.pmid: 11017233
references.citation: J Struct Biol. 2002 Jan-Feb;137(1-2):194-205
references.pmid: 12064946
references.citation: Proc Natl Acad Sci U S A. 2002 Apr 30;99 Suppl 2:6460-5
references.pmid: 11959907
references.citation: Phys Rev Lett. 2008 Dec 12;101(24):248301
references.pmid: 19113678
references.citation: Phys Rev Lett. 2008 Feb 29;100(8):085502
references.pmid: 18352635
references.citation: Biophys J. 2006 Nov 1;91(9):3446-55
references.pmid: 16905608
references.citation: Proc Natl Acad Sci U S A. 2006 Aug 22;103(34):12724-8
references.pmid: 16908850
references.citation: Science. 1996 Feb 9;271(5250):795-9
references.pmid: 8628994
references.citation: Nat Struct Biol. 2003 Sep;10(9):731-7
references.pmid: 12923573
references.citation: Science. 1997 May 16;276(5315):1112-6
references.pmid: 9148805
references.citation: Adv Biophys. 1996;33:123-34
references.pmid: 8922107
references.citation: Nat Mater. 2002 Dec;1(4):232-5
references.pmid: 12618784
references.citation: Biophys J. 1997 Apr;72(4):1541-55
references.pmid: 9083660
references.citation: Proteins. 1995 Mar;21(3):167-95
references.pmid: 7784423
references.citation: Proc Natl Acad Sci U S A. 2002 Oct 15;99(21):13544-8
references.pmid: 12374867
references.citation: Trends Biochem Sci. 1999 Oct;24(10):379-84
references.pmid: 10500301
references.citation: Biophys J. 2001 Feb;80(2):597-605
references.pmid: 11159428
references.citation: Biophys J. 2005 May;88(5):3494-501
references.pmid: 15731385
references.citation: Biophys J. 2007 Sep 1;93(5):1719-35
references.pmid: 17496052
references.citation: J Am Chem Soc. 2005 Jul 27;127(29):10188-90
references.pmid: 16028928
references.citation: Chemphyschem. 2002 Mar 12;3(3):255-61
references.pmid: 12503171
references.citation: Nature. 1998 May 14;393(6681):181-5
references.pmid: 9603523
references.citation: Science. 1997 Feb 28;275(5304):1295-7
references.pmid: 9036852
references.citation: Nature. 2002 Aug 29;418(6901):998-1002
references.pmid: 12198551
references.citation: J R Soc Interface. 2012 Nov 7;9(76):2911-22
references.pmid: 22696489
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Dec;82(6 Pt 1):061906
references.pmid: 21230689
references.citation: Nat Mater. 2009 Nov;8(11):910-6
references.pmid: 19838185
references.citation: Nat Mater. 2009 Mar;8(3):175-88
references.pmid: 19229265
references.citation: Cell. 2002 Feb 22;108(4):573-82
references.pmid: 11909527
references.citation: Biophys J. 1999 May;76(5):2439-47
references.pmid: 10233061
references.citation: Curr Opin Struct Biol. 2003 Feb;13(1):82-7
references.pmid: 12581664
references.citation: Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3694-9
references.pmid: 10097099
references.citation: Annu Rev Biophys. 2011;40:187-203
references.pmid: 21332356