Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Thermodynamics of force-induced B-DNA melting: Single-strand discreteness matters
Δημιουργός/Συγγραφέας:	[EL] Θεοδωρακόπουλος, Νίκος[EN] Theodorakopoulos, Nikos
Εκδότης:	American Physical Society
Ημερομηνία:	2019
Γλώσσα:	Αγγλικά
ISSN:	2470-0045
DOI:	10.1103/PhysRevE.99.032404
Άλλο:	PubMed ID: 30999428
Περίληψη:	Overstretching of B-DNA is currently understood as force-induced melting. Depending on the geometry of the stretching experiment, the force threshold for the overstretching transition is around 65 or 110 pN. Although the mechanisms behind force-induced melting have been correctly described by Rouzina and Bloomfield [Biophys. J. 80, 882 (2001)BIOJAU0006-349510.1016/S0006-3495(01)76067-5], neither force threshold has been exactly calculated by theory. In this work, a detailed analysis of the force-extension curve is presented, based on a description of single-stranded (ss) DNA in terms of the discrete Kratky-Porod model, consistent with (i) the contour length expected from the crystallographically determined monomer distance and (ii) a high value of the elastic stretch modulus arising from covalent bonding. The value estimated for the ss-DNA persistence length, λ=1.0 nm, is at the low end of currently known estimates and reflects the intrinsic stiffness of the partially, or fully stretched state, where electrostatic repulsion effects are expected to be minimal. A detailed analysis of single- and double-stranded DNA free energies provides estimates of the overstretching force thresholds. In the unconstrained geometry, the predicted threshold is 64 pN. In the constrained geometry, after allowing for the entropic penalty of the plectonemic topology of the molten state, the predicted threshold is 111 pN.
Τίτλος πηγής δημοσίευσης:	Physical Review E
Τόμος/Κεφάλαιο:	99
Τεύχος:	3
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© 2019 American Physical Society.
Όροι και προϋποθέσεις δικαιωμάτων:	All Open Access, Green
Σημειώσεις:	NSRF 2014-2020; European Commission, EC; European Regional Development Fund, FEDER I acknowledge support by the project Advanced Materials and Devices (MIS 5002409), implemented under the “Action for the Strategic Development on the Research and Technological Sector,” funded by the Operational Program Competitiveness, Entrepreneurship and Innovation (NSRF 2014-2020) and cofinanced by Greece and the European Union (European Regional Development Fund).
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο