Folding and unfolding of helix-turn-helix motifs in the gas phase
- 1 July 2007
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Society for Mass Spectrometry
- Vol. 18 (7), 1239-1248
- https://doi.org/10.1016/j.jasms.2007.03.027
Abstract
Ion mobility measurements and molecular dynamic simulations have been performed for a series of peptides designed to have helix-turn-helix motifs. For peptides with two helical sections linked by a short loop region: AcA14KG3A14K+2H+, AcA14KG5A14K+2H+, AcA14KG7A14K+2H+, and AcA14KSar3A14K+2H+ (Ac = acetyl, A = alanine, G = glycine, Sar = sarcosine and K = lysine); a coiled-coil geometry with two anti-parallel helices is the lowest energy conformation. The helices uncouple and the coiled-coil unfolds as the temperature is raised. Equilibrium constants determined as a function of temperature yield enthalpy and entropy changes for the unfolding of the coiled-coil. The enthalpy and entropy changes depend on the length and nature of the loop region. For a peptide with three helical sections: protonated AcA14KG3A14KG3A14K; a coiled-coil bundle with three helices side-by-side is substantially less stable than a geometry with two helices in an antiparallel coiled-coil and the third helix collinear with one of the other two.Keywords
This publication has 21 references indexed in Scilit:
- Extreme Stability of an Unsolvated α-HelixJournal of the American Chemical Society, 2004
- Helix−Turn−Helix Motifs in Unsolvated PeptidesJournal of the American Chemical Society, 2003
- Noncovalent Interactions between Unsolvated PeptidesThe Journal of Physical Chemistry A, 2002
- Peptide PinwheelsJournal of the American Chemical Society, 2002
- Conformations of Unsolvated Valine-Based PeptidesJournal of the American Chemical Society, 2000
- Conformations of Unsolvated Glycine-Based PeptidesThe Journal of Physical Chemistry B, 2000
- Design of Helices That Are Stable in VacuoJournal of the American Chemical Society, 1998
- Consistency in structural energetics of protein folding and peptide recognitionProtein Science, 1997
- Stability of α-HelicesPublished by Elsevier BV ,1995
- Crystal Structure of the Repetitive Segments of SpectrinScience, 1993