8AG9

Thermogutta terrifontis endoglucanase of glycoside hydrolase family 5 (TtEnd5A)

8AG9 の概要

• エントリーDOI: 10.2210/pdb8ag9/pdb
• 分子名称: Endoglucanase, SULFATE ION (3 entities in total)
• 機能のキーワード: thermogutta terrifontis endoglucanase of hg5 family, cellulase, apo structure, hydrolase
• 由来する生物種: Thermogutta terrifontis
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 58769.99

構造登録者

Hussain, N.,Mikolajek, H.,Naismith, J.H. (登録日: 2022-07-19, 公開日: 2022-08-17, 最終更新日: 2025-01-15)

主引用文献

Hussain, N.,Mikolajek, H.,Harrison, P.J.,Paterson, N.,Akhtar, M.W.,Sadaf, S.,Naismith, J.H.
Structural and functional snapshots of a broad-specificity endoglucanase from Thermogutta terrifontis for biomass saccharification.
Arch.Biochem.Biophys., 764:110274-110274, 2024

PubMed Abstract: Multifunctionality, processivity, and thermostability are critical for the cost-effective enzymatic saccharification of non-food plant biomass polymers such as β-glucans, celluloses, and xylans to generate biofuels and other valuable products. We present molecular insights into a processive multifunctional endo-1,3-1,4-β-d-glucanase (Tt_End5A) from the hyperthermophilic bacterium Thermogutta terrifontis. Tt_End5A demonstrated activities against a broad spectrum of β-polysaccharides, including barley glucan, lichenan, carboxymethyl cellulose, regenerated amorphous cellulose (RAC), Avicel, xylan, laminarin, mannan, curdlan, xanthan, and various chromogenic substrates at pH 7 and temperatures ranging from 70 to 80°C. The enzyme exhibited a high level of processivity on RAC and retained over 90% activity at 80°C for an extended period, indicating exceptional thermal stability. The 1.20 Å crystal structure of the Tt_End5A catalytic domain revealed an archetypal glycoside hydrolase family 5 (GH5) catalytic TIM-(β/α)-barrel, supplemented with additional β-strands, elongated α-helices, and a rare cis-non-Pro (His481-cis-Ala482) peptide. A large central cleft was observed in the 3D structure, which is likely related to the enzyme's multifunctionality and processivity. The catalytic domain is preceded by a novel N-terminal multivalent carbohydrate-binding module (CBM) that enhances the enzymatic degradation of insoluble polysaccharides. Mutagenesis studies, ligand interaction analyses, and the structurally conserved positions of E329 and E448 in Tt_End5A suggest that these residues function as the proton donor and nucleophile in the catalytic mechanism. Owing to its multifunctionality and processivity, Tt_End5A can reduce the need for multiple saccharification enzymes to generate fermentable sugars from plant biomass for bioethanol production. Additionally, it holds promise for applications in the pharmaceutical, feed, and food industries.

PubMed: 39701201
DOI: 10.1016/j.abb.2024.110274

実験手法

X-RAY DIFFRACTION (1.56 Å)