Glycoconjugate Journal

, Volume 26, Issue 4, pp 495–510

C1-/C2-aromatic-imino-glyco-conjugates: experimental and computational studies of binding, inhibition and docking aspects towards glycosidases isolated from soybean and jack bean

  • Amit Kumar
  • Nitin K. Singhal
  • Balaji Ramanujam
  • Atanu Mitra
  • Nagender R. Rameshwaram
  • Siva K. Nadimpalli
  • Chebrolu P. Rao
Article

DOI: 10.1007/s10719-008-9199-4

Cite this article as:
Kumar, A., Singhal, N.K., Ramanujam, B. et al. Glycoconj J (2009) 26: 495. doi:10.1007/s10719-008-9199-4

Abstract

Several C1-imino conjugates of d-galactose, d-lactose and d-ribose, where the nitrogen center was substituted by the salicylidene or naphthylidene, were synthesized and characterized. Similar C2-imino conjugates of d-glucose have also been synthesized. All the glyco-imino-conjugates, which are transition state analogues, exhibited 100% inhibition of the activity towards glycosidases extracted from soybean and jack bean meal. Among these, a galactosyl-napthyl-imine-conjugate (1c) showed 50% inhibition of the activity of pure α-mannosidase from jack bean at 22 ± 2.5 μM, and a ribosyl-naphthyl-imine-conjugate (3c) showed at 31 ± 5.5 μM and hence these conjugates are potent inhibitors of glycosidases. The kinetic studies suggested non-competitive inhibition by these conjugates. The studies are also suggestive of the involvement of aromatic, imine and carbohydrate moieties of the glyco-imino-conjugates in the effective inhibition. The binding of glyco-imino-conjugate has been established by extensive studies carried out using fluorescence emission and isothermal titration calorimetry. The conformational changes resulted in the enzyme upon interaction of these derivatives has been established by studying the fluorescence quench of the enzyme by KI as well as from the secondary structural changes noticed in CD spectra. All these studies revealed the difference in the binding strengths of the naphthylidene vs. salicylidene as well as galactosyl vs. lactosyl moieties present in these conjugates. The differential inhibition of these glyco-conjugates has been addressed by quantifying the specific interactions present between the glyco-conjugates and the enzyme by using rigid docking studies.

Keywords

C1-/C2-aromatic-imino-glyco-conjugates Glycosidase inhibition Pure α-mannosidase Rigid docking Fluorescence quenching Glycosidases from soybean and jack bean 

Supplementary material

10719_2008_9199_MOESM1_ESM.pdf (734 kb)
ESM 1Spectra for the glyco-conjugates (SI 01); enzyme assay (SI 02), enzyme inhibition data (SI 03), kinetics of inhibition (SI 04); fluorescence data (SI 05 & SI 06); CD spectra (SI 07); docked data (SI 08) (PDF 734 KB)

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Amit Kumar
    • 1
  • Nitin K. Singhal
    • 1
  • Balaji Ramanujam
    • 1
  • Atanu Mitra
    • 1
  • Nagender R. Rameshwaram
    • 2
  • Siva K. Nadimpalli
    • 2
  • Chebrolu P. Rao
    • 1
  1. 1.Bioinorganic Laboratory, Department of ChemistryIndian Institute of Technology BombayMumbaiIndia
  2. 2.Department of Biochemistry, School of Life SciencesUniversity of HyderabadHyderabadIndia

Personalised recommendations