2013年5月
Self-association of the galectin-9 C-terminal domain via the opposite surface of the sugar-binding site
JOURNAL OF BIOCHEMISTRY
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- 巻
- 153
- 号
- 5
- 開始ページ
- 463
- 終了ページ
- 471
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1093/jb/mvt009
- 出版者・発行元
- OXFORD UNIV PRESS
Galectin-9 is a lectin, which has various biological functions such as T-cell differentiation and apoptosis. Multivalency of carbohydrate binding is required for galectin-9 to function. Although galectin-1 (a proto-type galectin) forms an oligomer to obtain its multivalency, galectin-9 (a tandem-repeat-type one) has two carbohydrate recognition domains (CRD) in one polypeptide. However, a single CRD of galectin-9, especially the C-terminal one, exhibited pro-apoptotic activity suggesting oligomer formation capability. In this study, we monitored the nuclear magnetic resonance (NMR) signals of the backbone atoms of the galectin-9 C-terminal CRD (G9CCRD). Protein concentration dependence of the signals suggested that a region (F1-F4 strands) opposite to the ligand-binding site was involved in the self-association of G9CCRD. Site-directed mutagenesis in this region (Leu210, Trp277 and Leu279 to Thr; G9CCRD-3T) inhibited the self-association of G9CCRD, and improved the solubility, whereas it reduced its pro-apoptotic activity towards T cells. The high pro-apoptotic activity of G9CCRD seems to be due to the ability to form an oligomer. In addition, the same substitution in two-CRD-containing galectin-9 (G9Null-3T) also diminished the self-association and improved its solubility, although it hardly reduced the anti-proliferative and pro-apoptotic activities. G9CCRD contributes the self-association of full-length galectin-9 at high protein concentrations.
- リンク情報
- ID情報
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- DOI : 10.1093/jb/mvt009
- ISSN : 0021-924X
- Web of Science ID : WOS:000318561900008