Influence of side-chain-terminating moieties on the conformation of branched polypeptides and their conjugates with 4-ethoxymethylene-2-phenyl-5(4H)-oxazolone.
Poly(Lys-(Xi-DL-Alam] polypeptides carrying hydrophilic (X = His, Glu, Lys) or hydrophobic (X = Nle, Ile, Phe) amino acid residues and their conjugates with 4-ethoxymethylene-2-phenyl-5(4H)-oxazolone were synthesized. The conformational properties of carrier polypeptides and conjugates were studied by circular dichroism (CD) spectroscopy in the wavelength regions 190-250 and 310-380 nm, with the emphasis on analysis under near physiological conditions. Based on CD studies, it could be demonstrated that the helix-forming capacity appears to be related to the hydrophobic nature of the branch-terminating amino acid of the branched polypeptides. With respect to carrier function, the presence of a coupled derivative of oxazolone at the side chain termini generally promotes the formation of helical secondary structure. The absolute configuration of the side-chain-terminating amino acids was found to be important for the local orientation of the hapten molecule in the conjugates.
Hudecz
F
F
Department of Organic Chemistry, L. Eötvös University, Budapest, Hungary.
Kajtár
J
J
Szekerke
M
M
D002942:Circular Dichroism; D006241:Haptens; D008958:Models, Molecular; D010080:Oxazoles; D010081:Oxazolone; D010455:Peptides; D011487:Protein Conformation; D013329:Structure-Activity Relationship
D006241:Haptens; D010080:Oxazoles; D010455:Peptides; D010081:Oxazolone