Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (09): 1877-1885.doi: 10.3866/PKU.WHXB201306143

• THERMODYNAMICS, KINETICS, AND STRUCTURAL CHEMISTRY • Previous Articles     Next Articles

Molecular Recognition of Glycoconjugated Porphyrin with Chiral Amino Acid Methyl Ester

YANG Le-Le, LIU Jia, LI Yue, LIU Kun, RUAN Wen-Juan   

  1. Department of Chemistry, Nankai University, Tianjin 300071, P. R. China
  • Received:2013-04-19 Revised:2013-06-13 Published:2013-08-28
  • Contact: RUAN Wen-Juan E-mail:wjruan@nankai.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20671053).

Abstract:

Three atropisomeric tetrasaccharide-substituted zinc porphyrins (αβαβ-Zn-A, ααββ-Zn-A and αααβ-Zn-A) and one monosaccharide-substituted zinc porphyrin (Zn-B) were synthesized. We explored the interactions of these zinc porphyrins with a set of amino acid methyl esters (L/D-LeuOMe, L/ D-ThrOMe, L/D-ValOMe, and L/D-PheOMe)using visible titration and circular dichroism (CD) spectroscopy. We observed that all of them bind to L-amino acid methyl esters more closely than to those with D-configuration. In particular, ααββ-Zn-A gives a high enantioselectivity, KL/KD of 4.75, and could be used for chiral recognition of amino acid methyl esters. The binding constants of the three Zn-A compounds with methyl amino acid methyl esters are in the same order, i.e., Kθ(LeuOMe) > Kθ(ValOMe) > Kθ(ThrOMe) > Kθ(PheOMe), but the order of the binding constants for Kθ(PheOMe) > Kθ(LeuOMe) > Kθ(ValOMe) > Kθ(ThrOMe). In addition, we used imidazole as a probe to study the effects of achiral molecules on the conformations of the glycoconjugated porphyrins. The experimental results show that binding with imidazole causes adjustments in the conformations of the Zn-A compounds. The binding constants of the Zn-A compounds with imidazole and with methyl amino acid methyl esters are in the same order: Kθ(ααββ-Zn-A) > Kθ(αβαβ-Zn-A) > Kθ(αααβ-Zn-A).

Key words: Glycoconjugated porphyrin, Chiral recognition, Spectrum titration, Circular dichroism spectroscopy, Amino acid methyl ester

MSC2000: 

  • O641