1K1X

Crystal structure of 4-alpha-glucanotransferase from thermococcus litoralis

1K1X の概要

• エントリーDOI: 10.2210/pdb1k1x/pdb
• 関連するPDBエントリー: 1K1W 1K1Y
• 分子名称: 4-ALPHA-GLUCANOTRANSFERASE, CALCIUM ION, 2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, ... (4 entities in total)
• 機能のキーワード: 4-alpha-glucanotransferase, transferase
• 由来する生物種: Thermococcus litoralis
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 156220.60

構造登録者

Imamura, H.,Fushinobu, S.,Kumasaka, T.,Yamamoto, M.,Jeon, B.S.,Wakagi, T.,Matsuzawa, H. (登録日: 2001-09-26, 公開日: 2003-06-17, 最終更新日: 2024-03-13)

主引用文献

Imamura, H.,Fushinobu, S.,Yamamoto, M.,Kumasaka, T.,Jeon, B.S.,Wakagi, T.,Matsuzawa, H.
Crystal structures of 4-alpha-glucanotransferase from Thermococcus litoralis and its complex with an inhibitor
J.BIOL.CHEM., 278:19378-19386, 2003

PubMed Abstract: Thermococcus litoralis 4-alpha-glucanotransferase (TLGT) belongs to glucoside hydrolase family 57 and catalyzes the disproportionation of amylose and the formation of large cyclic alpha-1,4-glucan (cycloamylose) from linear amylose. We determined the crystal structure of TLGT with and without an inhibitor, acarbose. TLGT is composed of two domains: an N-terminal domain (domain I), which contains a (beta/alpha)7 barrel fold, and a C-terminal domain (domain II), which has a twisted beta-sandwich fold. In the structure of TLGT complexed with acarbose, the inhibitor was bound at the cleft within domain I, indicating that domain I is a catalytic domain of TLGT. The acarbose-bound structure also clarified that Glu123 and Asp214 were the catalytic nucleophile and acid/base catalyst, respectively, and revealed the residues involved in substrate binding. It seemed that TLGT produces large cyclic glucans by preventing the production of small cyclic glucans by steric hindrance, which is achieved by three lids protruding into the active site cleft, as well as an extended active site cleft. Interestingly, domain I of TLGT shares some structural features with the catalytic domain of Golgi alpha-mannosidase from Drosophila melanogaster, which belongs to glucoside hydrolase family 38. Furthermore, the catalytic residue of the two enzymes is located in the same position. These observations suggest that families 57 and 38 evolved from a common ancestor.

PubMed: 12618437
DOI: 10.1074/jbc.M213134200

実験手法

X-RAY DIFFRACTION (2.4 Å)