Premium
Ferric complexes of acetoacetyl derivatives of poly( L ‐lysine), poly( L ‐ornithine), and poly( L ‐diaminobutyric acid). II. Conformational properties in solution. Evidence for a stereospecific complex formation
Author(s) -
Palumbo M.,
Cosani A.,
Terbojevich M.,
Peggion E.
Publication year - 1976
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1976.360151112
Subject(s) - chemistry , stereospecificity , chromophore , lysine , stereochemistry , absorption (acoustics) , chirality (physics) , ligand (biochemistry) , ferric , helix (gastropod) , polymer chemistry , polymer , crystallography , amino acid , photochemistry , organic chemistry , biochemistry , ecology , physics , chiral symmetry breaking , receptor , quantum mechanics , snail , acoustics , nambu–jona lasinio model , biology , quark , catalysis
The conformational properties of ferric complexes of poly( N ε ‐acetoacetyl‐ L ‐lysine), poly( N δ ‐acetoacetyl‐ L ‐ornithine), and poly( N γ ‐acetoacetyl‐ L ‐diaminobutyric acid) were investigated in 1:1 water/dioxane by CD techniques. Optical activity was found in the visible and in the uv absorption region of the polymeric complexes. The conformation of the peptide backbone was always that of a right‐handed α‐helix, and was found independent of the degree of complexation, at least up to a degree of binding of 20%. In the absorption region of the side‐chain chromophores the optical activity is substantially affected by complex formation. In all three cases a splitting of the ligand π → π* transition centered at 257 nm is observed. These data suggest a stereospecific complex formation. From the signs of the splitting it also appears that the chirality of the poly( N δ ‐acetoacetyl‐ L ‐ornithine) complex is opposite that of the other two polymers.