title: Peptide chirality sensing by a cyclodextrin-polythiophene conjugate.
abstract: A new cyclodextrin-polythiophene conjugate (CDPT) has been prepared by attaching permethyl-α-cyclodextrins to polythiophene (PT) through a hexamethylene tether. Circular dichroism spectral examination of CDPT revealed that only a weak positive Cotton effect (Δε=0.1 M(-1) cm(-1)) was induced at the main band of the PT in dimethyl sulfoxide and similarly weak bisignate signals in pure and aqueous methanol solutions, which indicates that the α-cyclodextrins appended to PT with a long tether are ineffective in inducing a homochiral structure in the PT backbone. Nevertheless, enantiomeric amino acids and dipeptides added to an aqueous methanolic solution of CDPT caused chirality-dependent hypochromic changes in the UV/Vis spectra, which enabled us to sense these species and quantitatively determine the enantioselectivity by observing the difference in absorbance upon interaction with pairs of enantiomers. Enantiomeric D,D/L,L-dipeptide pairs rather than D/L-amino acid pairs were better differentiated in general, the highest DD/LL selectivity of 13.7 being observed for Phe-Phe.
authors: Department of Applied Chemistry, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan. gaku@chem.eng.osaka-u.ac.jp
authors: Gaku
authors: G
authors: Fukuhara
authors: Yoshihisa
authors: Y
authors: Inoue
mesh_terms: D003505:Cyclodextrins / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry*; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D003505:Cyclodextrins; D004151:Dipeptides; D011108:Polymers; D013876:Thiophenes; C066730:polythiophene