6TYR

Crystal structure of Laccase from Thermus thermophilus HB27 with a close conformation of its beta-hairpin

6TYR の概要

• エントリーDOI: 10.2210/pdb6tyr/pdb
• 分子名称: Laccase, GLYCEROL, CITRIC ACID, ... (5 entities in total)
• 機能のキーワード: close loop, laccase, multicopper oxidase, oxidoreductase
• 由来する生物種: Thermus thermophilus (strain HB27 / ATCC BAA-163 / DSM 7039)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 49450.50

構造登録者

Miranda-Blancas, R.,Rudino-Pinera, E. (登録日: 2019-08-09, 公開日: 2020-08-12, 最終更新日: 2023-10-11)

主引用文献

Miranda-Blancas, R.,Avelar, M.,Rodriguez-Arteaga, A.,Sinicropi, A.,Rudino-Pinera, E.
The beta-hairpin from the Thermus thermophilus HB27 laccase works as a pH-dependent switch to regulate laccase activity.
J.Struct.Biol., 213:107740-107740, 2021

PubMed Abstract: The multi-copper oxidase from the hyper-thermophilic bacteria Thermus thermophilus (Tth-MCO), has been previously characterized and described as an example of a laccase with low catalytic properties, especially when it is compared with the activity of fungal laccases, but it is active at high temperatures. Structurally, Tth-MCO has a unique feature: a β-hairpin near the T1Cu site, which is not present in any other laccases deposited at the PDB. This β-hairpin has an expected crystallographic behavior in solvent-exposed areas of a crystallized protein: lack of electron density, high B-values and several crystalline contacts with neighboring crystallographic copies; however, its dynamical behavior in solution and its biological implications have not been described. Here, we describe four new Tth-MCO crystallographic structures, and the β-hairpin behavior has been analyzed by molecular dynamics simulations, considering the effect of pH and temperature. The β-hairpin new crystallographic conformations described here, together with their dynamics, were used to understand the pH-restrained laccase activity of Tth-MCO against substrates as syringaldazine. Remarkably, there are insertions in laccases from Thermus and Meiothermus genus, sharing the same position and a methionine-rich composition of the Tth-MCO β-hairpin. This unique high methionine content of the Tth-MCO β-hairpin is responsible to coordinate, Ag and Hg in oxidative conditions, but Cu and Cu are not coordinated in crystallographic experiments, regardless of the redox conditions; however, Ag addition does not affect Tth-MCO laccase activity against syringaldazine. Here, we propose that the pH-dependent β-hairpin dynamical behavior could explain, at least in part, the inefficient laccase activity displayed by Tth-MCO in acidic pH values.

PubMed: 33962016
DOI: 10.1016/j.jsb.2021.107740

実験手法

X-RAY DIFFRACTION (1.813 Å)