Hydrogen bonding of beta-turn structure is stabilized in D(2)O.
The lower critical solution temperature (LCST) of elastin-like polypeptides (ELPs) was investigated as a function of ELP chain length and guest residue chemistry. These measurements were made in both D(2)O and H(2)O. Differences in the LCST values with heavy and light water were correlated with secondary structure formation of the polypeptide chains. Such structural information was obtained by circular dichroism and infrared measurements. Additional thermodynamic data were obtained by differential scanning calorimetry. It was found that there is a greater change in the LCST value between H(2)O and D(2)O for those polypeptides which form the greatest amount of beta-turn/beta-aggregate structure. Moreover, these same molecules were the least hydrophobic ELPs. Therefore, hydrogen bonding rather than hydrophobicity was the key factor in the stabilization of the collapsed state of ELPs in D(2)O compared with H(2)O.
Cho
Younhee
Y
Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, USA.
Sagle
Laura B
LB
Iimura
Satoshi
S
Zhang
Yanjie
Y
Kherb
Jaibir
J
Chilkoti
Ashutosh
A
Scholtz
J Martin
JM
Cremer
Paul S
PS
D002942:Circular Dichroism; D017666:Deuterium Oxide / Q000737:chemistry*; D004549:Elastin / Q000737:chemistry*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013696:Temperature
D010455:Peptides; D004549:Elastin; D017666:Deuterium Oxide