6AG0

The X-ray Crystallographic Structure of Maltooligosaccharide-forming Amylase from Bacillus stearothermophilus STB04

6AG0 の概要

• エントリーDOI: 10.2210/pdb6ag0/pdb
• 関連するBIRD辞書のPRD_ID: PRD_900007
• 分子名称: Alpha-amylase, 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, CALCIUM ION, ... (4 entities in total)
• 機能のキーワード: maltotetraose-forming amylase, bacillus stearothermophilus stb04, sugar binding protein
• 由来する生物種: Geobacillus stearothermophilus (Bacillus stearothermophilus)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 130579.75

構造登録者

Li, Z.F.,Li, Y.L.,Ban, X.F.,Zhang, C.Y.,Jin, T.C.,Xie, X.F.,Gu, Z.B.,Li, C.M. (登録日: 2018-08-09, 公開日: 2018-10-10, 最終更新日: 2023-11-22)

主引用文献

Xie, X.,Li, Y.,Ban, X.,Zhang, Z.,Gu, Z.,Li, C.,Hong, Y.,Cheng, L.,Jin, T.,Li, Z.
Crystal structure of a maltooligosaccharide-forming amylase from Bacillus stearothermophilus STB04.
Int.J.Biol.Macromol., 138:394-402, 2019

PubMed Abstract: To better understand structure-function relationships, an X-ray crystal structure of the maltooligosaccharide-forming amylase from Bacillus stearothermophilus STB04 (Bst-MFA) with bound acarbose has been determined at 2.2 Å. The structure revealed a classical three-domain fold stabilized by four calcium ions, in which CaI-CaIII form an unprecedented linear metal triad in the interior of domain B. Catalytic residues are deduced to be two aspartic acids and one glutamic acid (Asp234, Glu264, Asp331), and the acarbose is bound to surrounding amino acid residues, mainly through extensive hydrogen bonds. Furthermore, analysis of the structure indicates the existence of at least 8 subsites in Bst-MFA, six glycone sites (-6, -5, -4, -3, -2, -1) and two aglycone sites (+1, +2). Subsite +3 remains to be further explored. Sugar-binding subsites contribute to further presentation of the oligosaccharide-binding mode, which explains the product specificity of Bst-MFA to some extent. In addition, we propose a mechanism by which maltooligosaccharide-forming amylases produce particular maltooligosaccharide products, a result different from that seen with typical α-amylases. Finally, the three-dimensional structure of Bst-MFA complexed with acarbose provides the basis for further studies, designed to increase product specificity.

PubMed: 31325505
DOI: 10.1016/j.ijbiomac.2019.07.104

実験手法

X-RAY DIFFRACTION (2.2 Å)