6M4M

X-ray crystal structure of the E249Q mutan of alpha-amylase I and maltohexaose complex from Eisenia fetida

6M4M の概要

• エントリーDOI: 10.2210/pdb6m4m/pdb
• 関連するBIRD辞書のPRD_ID: PRD_900010 PRD_900035
• 分子名称: Alpha-amylase, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, ... (9 entities in total)
• 機能のキーワード: tim barrel, gh family 13, carbohydrase, cold-active, hydrolase
• 由来する生物種: Eisenia fetida (Red wiggler worm)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 61002.68

構造登録者

Hirano, Y.,Tsukamoto, K.,Ariki, S.,Naka, Y.,Ueda, M.,Tamada, T. (登録日: 2020-03-07, 公開日: 2020-09-16, 最終更新日: 2024-10-23)

主引用文献

Hirano, Y.,Tsukamoto, K.,Ariki, S.,Naka, Y.,Ueda, M.,Tamada, T.
X-ray crystallographic structural studies of alpha-amylase I from Eisenia fetida.
Acta Crystallogr D Struct Biol, 76:834-844, 2020

PubMed Abstract: The earthworm Eisenia fetida possesses several cold-active enzymes, including α-amylase, β-glucanase and β-mannanase. E. fetida possesses two isoforms of α-amylase (Ef-Amy I and II) to digest raw starch. Ef-Amy I retains its catalytic activity at temperatures below 10°C. To identify the molecular properties of Ef-Amy I, X-ray crystal structures were determined of the wild type and of the inactive E249Q mutant. Ef-Amy I has structural similarities to mammalian α-amylases, including the porcine pancreatic and human pancreatic α-amylases. Structural comparisons of the overall structures as well as of the Ca-binding sites of Ef-Amy I and the mammalian α-amylases indicate that Ef-Amy I has increased structural flexibility and more solvent-exposed acidic residues. These structural features of Ef-Amy I may contribute to its observed catalytic activity at low temperatures, as many cold-adapted enzymes have similar structural properties. The structure of the substrate complex of the inactive mutant of Ef-Amy I shows that a maltohexaose molecule is bound in the active site and a maltotetraose molecule is bound in the cleft between the N- and C-terminal domains. The recognition of substrate molecules by Ef-Amy I exhibits some differences from that observed in structures of human pancreatic α-amylase. This result provides insights into the structural modulation of the recognition of substrates and inhibitors.

PubMed: 32876059
DOI: 10.1107/S2059798320010165

実験手法

X-RAY DIFFRACTION (1.7 Å)