1GYM

PHOSPHATIDYLINOSITOL-SPECIFIC PHOSPHOLIPASE C IN COMPLEX WITH GLUCOSAMINE-(ALPHA-1-6)-MYO-INOSITOL

1GYM の概要

• エントリーDOI: 10.2210/pdb1gym/pdb
• 分子名称: PHOSPHATIDYLINOSITOL-SPECIFIC PHOSPHOLIPASE C, (1R,2R,3R,4R,5R,6S)-2,3,4,5,6-pentahydroxycyclohexyl 2-amino-2-deoxy-alpha-D-glucopyranoside (3 entities in total)
• 機能のキーワード: phosphatidylinositol specific phospholipase c, glucosaminyl (alpha-1-6)-d-myo-inositol, inhibitor complex, hydrolase (phosphoric diester), lipid degradation
• 由来する生物種: Bacillus cereus
• 細胞内の位置: Secreted: P14262
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 34909.98

構造登録者

Heinz, D.W.,Ryan, M.,Smith, M.P.,Weaver, L.H.,Keana, J.F.W.,Griffith, O.H. (登録日: 1996-05-02, 公開日: 1996-11-08, 最終更新日: 2024-02-07)

主引用文献

Heinz, D.W.,Ryan, M.,Smith, M.P.,Weaver, L.H.,Keana, J.F.,Griffith, O.H.
Crystal structure of phosphatidylinositol-specific phospholipase C from Bacillus cereus in complex with glucosaminyl(alpha 1-->6)-D-myo-inositol, an essential fragment of GPI anchors.
Biochemistry, 35:9496-9504, 1996

PubMed Abstract: Numerous proteins on the external surface of the plasma membrane are anchored by glycosylated derivatives of phosphatidylinositol (GPI), rather than by hydrophobic amino acids embedded in the phospholipid bilayer. These GPI anchors are cleaved by phosphatidylinositol-specific phospholipases C (PI-PLCs) to release a water-soluble protein with an exposed glycosylinositol moiety and diacylglycerol, which remains in the membrane. We have previously determined the crystal structure of Bacillus cereus PI-PLC, the enzyme which is widely used to release GPI-anchored proteins from membranes, as free enzyme and also in complex with myo-inositol [Heinz, D.W., Ryan, M. Bullock, T.L., & Griffith, O. H. (1995) EMBO J. 14, 3855-3863]. Here we report the refined 2.2 A crystal structure of this enzyme complexed with a segment of the core of all GPI anchors, glucosaminyl(alpha 1-->6)-D-myo-inositol [GlcN-(alpha 1-->6)Ins ]. The myo-inositol moiety of GlcN(alpha 1-->6)Ins is well-defined and occupies essentially the same position in the active site as does free myo-inositol, which provides convincing evidence that the enzyme utilizes the same catalytic mechanism for cleavage of PI and GPI anchors. The myo-inositol moiety makes several specific hydrogen bonding interactions with active site residues. In contrast, the glucosamine moiety lies exposed to solvent at the entrance of the active site with minimal specific protein contacts. The glucosamine moiety is also less well-defined, suggesting enhanced conformational flexibility. On the basis of the positioning of GlcN(alpha 1-->6)Ins in the active site, it is predicted that the remainder of the GPI-glycan makes little or no specific interactions with B. cereus PI-PLC. This explains why B. cereus PI-PLC can cleave GPI anchors having variable glycan structures.

PubMed: 8755729
DOI: 10.1021/bi9606105

実験手法

X-RAY DIFFRACTION (2.2 Å)