運用核磁共振分析Galectin-3與乳糖和胜肽之結合

NMR analysis of the Lactose and Peptide Binding to Galectin-3 Protein

許德芬(Te-Fen Hsu)

指導教授 ： 張壽麟

國立清華大學/生命科學院/生物資訊與結構生物研究所/碩士(2011年)

摘要

The Galectin-3 protein is a family of animal lectins that has affinity for β-galactosides through a conserved carbohydrate-recognition domain (CRD). Galectin-3 not only exists in old species but also in mammals, implying that Glaectin-3 plays an important and essential role in cell biology. Galectin-3 has been considered related to cell growth and differentiation, apoptosis and immune response. Most important of all, the expression of Galectin-3 increases in many types of cancer such as thyroid and pancreas cancer. Galectin-3 can facilitate metastasis by promoting cancer cell adhesion and invasiveness. In this research, CRD domain and full length Galectin-3 were used to study their affinity to lactose and a small synthetic peptide. From the NMR HSQC mapping of CRD, twenty-three residues were found to be affected upon binding where residues Arg144, Asn160, Asn174, Trp181, Glu184 and Arg186 were consistent with the previous X-ray results by Collins, et al. showing that they are in the vicinity of the lactose binding site. For the full-length Galectin-3, similar results were obtained. In the peptide-galectin binding experiments, no significant differences were found between free and peptide-titrated samples in the HSQC spectra. The synthetic peptide might bind to the protein in a non-specific way at high concentration which reduces the solubility of Galectin-3 and induces the formation of precipitations. This research work is served as a pilot study for our future work on the protein binding affinity and specificity using Galectin-3 as a model system.

關鍵字

乳糖

並列摘要

無資料

並列關鍵字

Galectin-3

參考文獻

Ahmad, N., H. J. Gabius, et al. (2004). "Thermodynamic binding studies of bivalent oligosaccharides to galectin-1, galectin-3, and the carbohydrate recognition domain of galectin-3." Glycobiology 14(9): 817-825.

Barondes, S. H., V. Castronovo, et al. (1994). "Galectins: a family of animal beta-galactoside-binding lectins." Cell 76(4): 597-598.

Collins, P. M., K. I. Hidari, et al. (2007). "Slow diffusion of lactose out of galectin-3 crystals monitored by X-ray crystallography: possible implications for ligand-exchange protocols." Acta Crystallogr D Biol Crystallogr 63(Pt 3): 415-419.

Cooper, D. N. (2002). "Galectinomics: finding themes in complexity." Biochim Biophys Acta 1572(2-3): 209-231.

Dagher, S. F., J. L. Wang, et al. (1995). "Identification of galectin-3 as a factor in pre-mRNA splicing." Proc Natl Acad Sci U S A 92(4): 1213-1217.