1ESW

X-RAY STRUCTURE OF ACARBOSE BOUND TO AMYLOMALTASE FROM THERMUS AQUATICUS. IMPLICATIONS FOR THE SYNTHESIS OF LARGE CYCLIC GLUCANS

1ESW の概要

• エントリーDOI: 10.2210/pdb1esw/pdb
• 関連するPDBエントリー: 1CWY
• 関連するBIRD辞書のPRD_ID: PRD_900007
• 分子名称: AMYLOMALTASE, 4,6-dideoxy-4-{[(1S,4R,5S,6S)-4,5,6-trihydroxy-3-(hydroxymethyl)cyclohex-2-en-1-yl]amino}-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, 1,2-ETHANEDIOL, ... (4 entities in total)
• 機能のキーワード: (beta, alpha)8-barrel, glucanotransferase, alpha-amylase family, acarbose, transferase
• 由来する生物種: Thermus aquaticus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 58708.39

構造登録者

Przylas, I.,Terada, Y.,Fujii, K.,Takaha, T.,Saenger, W.,Straeter, N. (登録日: 2000-04-11, 公開日: 2001-04-11, 最終更新日: 2024-02-07)

主引用文献

Przylas, I.,Terada, Y.,Fujii, K.,Takaha, T.,Saenger, W.,Strater, N.
X-ray structure of acarbose bound to amylomaltase from Thermus aquaticus. Implications for the synthesis of large cyclic glucans.
Eur.J.Biochem., 267:6903-6913, 2000

PubMed Abstract: As a member of the alpha-amylase superfamily of enzymes, amylomaltase catalyzes either the transglycosylation from one alpha-1,4 glucan to another or an intramolecular cyclization. The latter reaction is typical for cyclodextrin glucanotransferases. In contrast to these enzymes, amylomaltase catalyzes the formation of cyclic glucans with a degree of polymerization larger than 22. To characterize the factors that determine the size of the synthesized cycloamyloses, we have analyzed the X-ray structure of amylomaltase from Thermus aquaticus in complex with the inhibitor acarbose, a maltotetraose derivative, at 1.9 A resolution. Two acarbose molecules are bound to the enzyme, one in the active site groove at subsite -3 to +1 and a second one approximately 14 A away from the nonreducing end of the acarbose bound to the catalytic site. The inhibitor bound to the catalytic site occupies subsites -3 to +1. Unlike the situation in other enzymes of the alpha-amylase family, the inhibitor is not processed and the inhibitory cyclitol ring of acarbose, which mimicks the half chair conformation of the transition state, does not bind to catalytic subsite -1. The minimum ring size of cycloamyloses produced by this enzyme is proposed to be determined by the distance of the specific substrate binding sites at the active site and near Tyr54 and by the size of the 460s loop. The 250s loop might be involved in binding of the substrate at the reducing end of the scissile bond.

PubMed: 11082203

実験手法

X-RAY DIFFRACTION (1.9 Å)