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.
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 degrees C and from ambient pressure up to approximately 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 approximately 36 degrees 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.
Nicolini
C
C
Department of Chemistry, University of Dortmund, Dortmund, Germany.
Ravindra
R
R
Ludolph
B
B
Winter
R
R
D040761:Biomimetic Materials / Q000737:chemistry*; D004549:Elastin / Q000737:chemistry*; D004735:Energy Transfer; D008422:Materials Testing; D009842:Oligopeptides / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D044367:Phase Transition; D011312:Pressure; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013696:Temperature
D009842:Oligopeptides; D010455:Peptides; C094883:valyl-prolyl-glycyl-valyl-glycine; D004549:Elastin