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6M4K

X-ray crystal structure of wild type alpha-amylase I from Eisenia fetida

Summary for 6M4K
Entry DOI10.2210/pdb6m4k/pdb
DescriptorAlpha-amylase, CALCIUM ION, CHLORIDE ION, ... (8 entities in total)
Functional Keywordstim barrel, gh family 13, carbohydrase, cold-active, hydrolase
Biological sourceEisenia fetida (Red wiggler worm)
Total number of polymer chains1
Total formula weight59591.54
Authors
Hirano, Y.,Tsukamoto, K.,Ariki, S.,Naka, Y.,Ueda, M.,Tamada, T. (deposition date: 2020-03-07, release date: 2020-09-16, Last modification date: 2023-11-29)
Primary citationHirano, 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
Cited by
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
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (1.3 Å)
Structure validation

226707

數據於2024-10-30公開中

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