title: Hemodextrin: a self-assembled cyclodextrin-porphyrin construct that binds dioxygen.
abstract: Synthetic hemoprotein model compounds are of great interest due to the vital roles and complexities of hemoproteins. This study reports a novel, self-assembled hemoprotein model, hemodextrin. The synthesis and characterization of py-PPCD (2(A)-monopyridylmethyl-perPEGylated-beta-cyclodextrin) (2) is described. The molecular design is based on a pegylated cyclodextrin scaffold that bears both a heme-binding pocket and an axial ligand that binds an iron porphyrin. The binding constant for Fe(III)TPPS [iron(III) meso-tetra(4-sulphonatophenyl)porphyrin] by py-PPCD (2) was determined to be 2 x 10(6) M(-1) at pH 6.0 by observing characteristic changes in the UV-Vis spectrum of the porphyrin. The pyridyl nitrogen of py-PPCD (2) was shown to ligate to the iron center by observing signal changes in the Fe(II)-porphyrin 1H-NMR spectrum. This hemodextrin ensemble was shown to bind dioxygen reversibly and to form a stable ferryl species.
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000737:chemistry; D003505:Cyclodextrins / Q000737:chemistry; D006801:Humans; D007501:Iron / Q000737:chemistry; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*
chemical_list: D003505:Cyclodextrins; D008665:Metalloporphyrins; D002248:Carbon Monoxide; D007501:Iron; D010100:Oxygen