1M53

CRYSTAL STRUCTURE OF ISOMALTULOSE SYNTHASE (PALI) FROM KLEBSIELLA SP. LX3

1M53 の概要

• エントリーDOI: 10.2210/pdb1m53/pdb
• 関連するPDBエントリー: 1G5A 1UOK
• 分子名称: Isomaltulose Synthase (2 entities in total)
• 機能のキーワード: klebsiella sp. lx3, isomaltulose synthase, sucrose isomerization, isomerase
• 由来する生物種: Klebsiella sp. LX3
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 67251.80

構造登録者

Li, N.,Swaminathan, K. (登録日: 2002-07-08, 公開日: 2003-07-08, 最終更新日: 2023-10-25)

主引用文献

Zhang, D.,Li, N.,Lok, S.M.,Zhang, L.-H.,Swaminathan, K.
Isomaltulose synthase (PalI) of Klebsiella sp. LX3. Crystal structure and implication of mechanism
J.Biol.Chem., 278:35428-35434, 2003

PubMed Abstract: Isomaltulose synthase from Klebsiella sp. LX3 (PalI, EC 5.4.99.11) catalyzes the isomerization of sucrose to produce isomaltulose (alpha-D-glucosylpyranosyl-1,6-D-fructofuranose) and trehalulose (alpha-D-glucosylpyranosyl-1,1-d-fructofuranose). The PalI structure, solved at 2.2-A resolution with an R-factor of 19.4% and Rfree of 24.2%, consists of three domains: an N-terminal catalytic (beta/alpha)8 domain, a subdomain between N beta 3 and N alpha 3, and a C-terminal domain having seven beta-strands. The active site architecture of PalI is identical to that of other glycoside hydrolase family 13 members, suggesting a similar mechanism in substrate binding and hydrolysis. However, a unique RLDRD motif in the proximity of the active site has been identified and shown biochemically to be responsible for sucrose isomerization. A two-step reaction mechanism for hydrolysis and isomerization, which occurs in the same pocket is proposed based on both the structural and biochemical data. Selected C-terminal truncations have been shown to reduce and even abolish the enzyme activity, consistent with the predicted role of the C-terminal residues in the maintenance of enzyme conformation and active site topology.

PubMed: 12819210
DOI: 10.1074/jbc.M302616200

実験手法

X-RAY DIFFRACTION (2.2 Å)