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© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Tetrathionate hydrolase (TTH) is a key enzyme for the oxidation of reduced inorganic sulfur compounds (RISCs) with the S4I pathway, which is distributed in autotrophic or facultative autotrophic sulfur-oxidizing bacteria and archaea. In this study, the enzyme TTHMc from the acidothermophilic archaeon Metallosphaera cuprina Ar-4T, encoded by mcup_1281 and belonging to the pyrroloquinoline quinone (PQQ) family, has been shown to possess tetrathionate hydrolysis activity. The molecular mass of the single subunit of TTHMc was determined to be 57 kDa. TTHMc is proved to be located in the cytoplasm, periplasmic space, and membrane, and the activity of them accounted for 72.3%, 24.0%, and 3.7% of the total activity. Optimal activity was observed at temperatures above 95 °C and pH 6.0, and the kinetic constants Km and Vmax were 0.35 mmol/L and 86.3 μmol/L, respectively. The presence of 0.01 mol/L Mg2+ enhances the activity of TTHMc, while 0.01 mol/L Ca2+ inhibits its activity. The hydrolysis of tetrathionate (TT) by TTHMc results in the production of thiosulfate, pentathionate, and hexathionate. This study represents the first description of TTH in the genus Metallosphaera, providing new theoretical insights into the study of sulfur-oxidizing proteins in acidothermophilic archaea.

Details

Title
Characterization of Tetrathionate Hydrolase from Acidothermophilic Sulfur-Oxidizing Archaeon Metallosphaera cuprina Ar-4
Author
Wang, Pei 1 ; Liang-Zhi, Li 2   VIAFID ORCID Logo  ; Li-Jun, Liu 3 ; Ya-Ling, Qin 1 ; Xiu-Tong, Li 1 ; Hua-Qun Yin 2 ; De-Feng, Li 1 ; Shuang-Jiang, Liu 1   VIAFID ORCID Logo  ; Cheng-Ying, Jiang 1   VIAFID ORCID Logo 

 State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; [email protected] (P.W.); [email protected] (Y.-L.Q.); [email protected] (X.-T.L.); [email protected] (D.-F.L.); University of Chinese Academy of Sciences, Beijing 100049, China 
 School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China; [email protected] (L.-Z.L.); [email protected] (H.-Q.Y.) 
 School of Basic Medical Science, Xi’an Medical University, Xi’an 710021, China; [email protected] 
First page
1338
Publication year
2025
Publication date
2025
Publisher
MDPI AG
ISSN
16616596
e-ISSN
14220067
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3165902769
Copyright
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.