NMR and modeling studies of protein-carbohydrate interactions: synthesis, three-dimensional structure, and recognition properties of a minimum hevein domain with binding affinity for chitooligosaccharides
HEV32, a 32-residue, truncated hevein lacking eleven C-terminal amino acids, was synthesized by solid-phase methodology and correctly folded with three cysteine bridge pairs. The affinities of HEV32 for small chitin fragments--in the forms of N,N',N"-triacetylchitotriose ((GlcNAc)3) (millimolar) and N,N',N",N"',N"",N""'-hexaacetylchitohexaose ((GlcNAc)6) (micromolar)--as measured by NMR and fluorescence methods, are comparable with those of native hevein ...
HEV32, a 32-residue, truncated hevein lacking eleven C-terminal amino acids, was synthesized by solid-phase methodology and correctly folded with three cysteine bridge pairs. The affinities of HEV32 for small chitin fragments--in the forms of N,N',N"-triacetylchitotriose ((GlcNAc)3) (millimolar) and N,N',N",N"',N"",N""'-hexaacetylchitohexaose ((GlcNAc)6) (micromolar)--as measured by NMR and fluorescence methods, are comparable with those of native hevein. The HEV32 ligand-binding process is enthalpy driven, while entropy opposes binding. The NMR structure of ligand-bound HEV32 in aqueous solution was determined to be highly similar to the NMR structure of ligand-bound hevein. Solvated molecular-dynamics simulations were performed in order to monitor the changes in side-chain conformation of the binding site of HEV32 and hevein upon interaction with ligands. The calculations suggest that the Trp21 side-chain orientation of HEV32 in the free form differs from that in the bound state; this agrees with fluorescence and thermodynamic data. HEV32 provides a simple molecular model for studying protein-carbohydrate interactions and for understanding the physiological relevance of small native hevein domains lacking C-terminal residues.
Related Citations:
The interaction of hevein with N-acetylglucosamine-containing oligosaccharides. Solution structure of hevein complexed to chitobiose Asensio, J.L., Canada, F.J., Bruix, M., Rodriguez-Romero, A., Jimenez-Barbero, J. (1995) Eur J Biochem 230: 621
H NMR study of the solution structure of Ac-AMP2, a sugar binding antimicrobial protein isolated from amaranthus caudatus Martins, J.C., Maes, D., Loris, R., Pepermans, H.A., Wyns, L., Willem, R., Verheyden, P. (1996) J Mol Biol 258: 322
NMR investigations of protein-carbohydrate interactions: refined three-dimensional structure of the complex between hevein and methyl beta-chitobioside Asensio, J.L., Canada, F.J., Bruix, M., Gonzalez, C., Khiar, N., Rodriguez-Romero, A., Jimenez-Barbero, J. (1998) Glycobiology 8: 569
NMR Investigations of Protein-Carbohydrate Interactions: Studies on the Relevance of Trp/Tyr Variations in Lectin Binding Sites as Deduced from Titration Microcalorimetry and NMR Studies on Hevein Domains. Determination of the NMR Structure of the Complex between Pseudohevein and N'N',N''-triacetylchitotriose Asensio, J.L., Siebert, H.-C., von der Lieth, C.-W., Laynez, J., Bruix, M., Soedjanaamadja, U.M., Beintema, J.J., Canada, F.J., Gabius, H.-J., Jimenez-Barbero, J. (2000) Proteins 40: 218
Structural basis for chitin recognition by defense proteins: GlcNAc residues are bound in a multivalent fashion by extended binding sites in hevein domains Asensio, J.L., Canada, F.J., Siebert, H.-C., Laynez, J., Poveda, A., Nieto, P.M., Soedjanaamadja, U.M., Gabius, H.-J., Jimenez-Barbero, J. (2000) Chem Biol 7: 529
Organizational Affiliation:
Department of Protein Structure and Function, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
Download Mendeley
