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08:31
Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition
Published on: October 3, 2018
Molecular evolution of bacterial indoleamine 2,3-dioxygenase
Hajime J Yuasa1, Akiko Ushigoe, Helen J Ball
1Laboratory of Biochemistry, Department of Applied Science, National University Corporation Kochi University, Japan. julie@kochi-u.ac.jp
Gene
|June 22, 2011
Summary
Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are key enzymes in L-Trp metabolism. This study reveals bacterial IDOs with functions similar to mammalian enzymes, particularly in Gemmatimonas aurantiaca.
Area of Science:
- Biochemistry
- Enzymology
- Microbial Genomics
Background:
- Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are crucial enzymes in L-tryptophan (L-Trp) catabolism via the kynurenine pathway.
- While TDO is widespread and primarily involved in NAD(+) supply in mammals and bacteria, active IDO is found in vertebrates and fungi, playing roles in immunity (mammals) or NAD(+) supply (fungi).
Purpose of the Study:
- To investigate the presence and characteristics of putative indoleamine 2,3-dioxygenase (IDO) genes in bacterial species.
- To understand the evolutionary origins and functional significance of bacterial IDOs, particularly in relation to L-Trp metabolism and NAD(+) biosynthesis.
Main Methods:
- Genomic database searches for bacterial IDO genes.
- Phylogenetic analysis to classify bacterial IDOs into groups.
- Enzymatic characterization of bacterial IDOs, including kinetic parameters and inhibitor selectivity.
- Comparative analysis of gene clustering with kynurenase (kynU) and other metabolic genes.
Main Results:
- Bacterial IDOs were classified into two groups: group I with low catalytic efficiency and group II with high efficiency.
- Gemmatimonas aurantiaca IDO exhibited enzymatic characteristics comparable to mammalian IDO1, despite a lack of close evolutionary relationship.
- The IDO gene in G. aurantiaca is clustered with kynU, suggesting a functional role analogous to eukaryotic enzymes in L-Trp metabolism and NAD(+) production.
Conclusions:
- Group I bacterial IDOs likely arose independently through horizontal gene transfer and may not significantly contribute to L-Trp metabolism.
- Group II bacterial IDOs, exemplified by G. aurantiaca IDO, possess high catalytic efficiency and potentially fulfill functions similar to eukaryotic IDOs.
- The gene clustering of IDO with kynU in G. aurantiaca highlights a conserved functional module for L-Trp catabolism and NAD(+) biosynthesis across different domains of life.
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