Title
Characterization of the Temperature- and Pressure-Induced Inverse and Reentrant Transition of the Minimum Elastin-Like Polypeptide GVG(VPGVG) by DSC, PPC, CD, and FT-IR Spectroscopy
Author
C. Nicolini, R. Ravindra, B. Ludolph, R. Winter
Year
2004
Journal
Biophysical Journal
Abstract
We investigated the temperature- and pressure-dependent structure and phase behavior of a solvated oligopeptide, GVG(VPGVG), which serves as a minimalistic elastin-like model system, over a large region of the thermodynamic phase field, ranging from 2 to 120°C and from ambient pressure up to ∼10 kbar, applying various spectroscopic (CD, FT-IR) and thermodynamic (DSC, PPC) measurements. We find that this octapeptide behaves as a two-state system which undergoes the well-known inverse-temperature folding transition occurring at T ≈ 36°C, and, in addition, a slow trend reversal at higher temperatures, finally leading to a reentrant unfolding close to the boiling point of water. Furthermore, the pressure-dependence of the folding/unfolding transition was studied to yield a more complete picture of the p, T-stability diagram of the system. A molecular-level picture of these processes, in particular on the role of water for the folding and unfolding events of the peptide, presented with the help of molecular-dynamics simulations, is presented in a companion article in this issue.
Instrument
J-715
Keywords
Circular dichroism, Secondary structure, Thermodynamics, Thermal stability, Biochemistry