Studies on the enzymatic chemistry involved in the inorganic sulfur metabolism and its application.

2016 Fiscal Year Final Research Report

• Project/Area Number: 26450482
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental agriculture(including landscape science)
• Research Institution: Okayama University
• Principal Investigator: Kanao Tadayoshi 岡山大学, 環境生命科学研究科, 准教授 (40379813)
• Co-Investigator(Renkei-kenkyūsha): TAMADA Taro 国立研究開発法人量子科学技術研究開発機構, 上席研究員 (50391248) ; KAMIMURA Kazuo 岡山大学, 大学院環境生命科学研究科, 教授 (80294445)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 硫黄酸化細菌 / 硫黄代謝 / 無機硫黄化合物 / 脱硫硫黄 / 酵素化学 / 酵素の結晶構造解析

Outline of Final Research Achievements

This study has been performed to progress our knowledge about the enzymes involved in the dissimilatory inorganic sulfur metabolism in sulfur-oxidizing bacteria. We have isolated and identified the gene encoding tetrathionate hydrolase (<i>Af-tth</i>) which is the key enzyme in the metabolism in sulfur-oxidizing bacterium, <i>Acidithiobacillus ferrooxidans</i>. The recombinant <i>Af</i>-Tth was successfully obtained as an active form by new refolding method under acidic condition. The enzyme was crystalized to apply X-ray diffraction analysis. The 3D structure of <i>Af</i>-Tth has been determined by MAD/SAD methods with the Se-methionylated enzyme. The active center was also determined by the X-ray diffraction analysis of the crystal with tetrathionate. No cysteine residue was observed around the active center in the enzyme. It suggested that the enzyme has a unique cysteine independent reaction distinct from almost all other enzymes concerning dissimilatory sulfur-metabolism.

Free Research Field

応用微生物学