Stimuli-responsivity of secondary structures of glycopolypeptides derived from poly(L-glutamate-co-allylglycine).
Copolypeptides containing L-glutamate and various amounts of either D-/DL-/L-allylglycine or D-/DL-/L-(3-(β-D-glucopyranosyl)thio)propylglycine defect units were studied by circular dichroism (CD) and infrared (FT-IR) spectroscopy according to their secondary structures in dependence of pH and temperature. All samples adopt random coil conformation at high pH and α-helix at low pH without evidence for β-sheet formation. Folding into the α-helix structure is strongly affected by the number and configuration of allylglycine defects (which intrinsically stabilize β-sheets). Helix folding is facilitated upon the attachment of D-glucopyranose to the L- (but not the D-) allylglycine units, which is attributed to a different secondary structure preference of the L-(3-(β-D-glucopyranosyl)thio)propylglycine (L: random coil; D: β-sheet) and a majority rule effect.
Max Planck Institute of Colloids and Interfaces , Department of Colloid Chemistry, Research Campus Golm, 14424 Potsdam, Germany.
Kai-Steffen
KS
Krannig
Jing
J
Sun
Helmut
H
Schlaad
D000501:Allylglycine / Q000737:chemistry*; D002942:Circular Dichroism; D018698:Glutamic Acid / Q000737:chemistry*; D006020:Glycopeptides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D006020:Glycopeptides; D000501:Allylglycine; D018698:Glutamic Acid