Steroid-porphyrin conjugate for saccharide sensing in protic media.
A new saccharide receptor in protic media has been designed and synthesized. The receptor combines advantages of steroids, which are responsible for saccharide binding, and of the porphyrin moiety acting as a signalling component of the molecule due to changes in UV-vis electronic spectra. The synthesis is based on condensation of steroid aldehyde with pyrrole to form the porphyrin unit with four protected steroid moieties. After deprotection, meso-substituted porphyrin contains 12-hydroxy groups on the steroidal part. The receptor is soluble in aqueous solutions and exhibits high complexation affinity towards saccharides. Because the receptor extensively aggregates in water, most of the experiments were performed in 50% aqueous 2-propanol where aggregation is significantly eliminated. Binding is evidenced by spectral changes in the Soret region of the receptor in UV-vis absorption spectra allowing the evaluation of the binding constants. Additional confirmation of binding is obtained using 1H NMR, Raman and IR spectroscopies and the surface plasmon resonance technique. The receptor exhibits higher selectivity for oligosaccharides over monosaccharide. The results point to the importance of a combination of multiple binding via H-bonding and hydrophobic interactions.
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.
Mykhaylo
M
Dukh
David
D
Saman
Kamil
K
Lang
Vladimir
V
Pouzar
Ivan
I
Cerný
Pavel
P
Drasar
Vladimír
V
Král
D015374:Biosensing Techniques; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000032:analysis*; D002352:Carrier Proteins / Q000138:chemical synthesis* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008320:Maltose / Q000032:analysis / Q000378:metabolism; D015394:Molecular Structure; D009844:Oligosaccharides / Q000032:analysis / Q000378:metabolism; D011166:Porphyrins / Q000737:chemistry*; D011956:Receptors, Cell Surface; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013256:Steroids / Q000737:chemistry*; D020349:Surface Plasmon Resonance
D002241:Carbohydrates; D002352:Carrier Proteins; D009844:Oligosaccharides; D011166:Porphyrins; D011956:Receptors, Cell Surface; D013256:Steroids; C055213:saccharide-binding proteins; C019193:maltopentaose; D008320:Maltose