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Heterologous expression and functional characterization of cysteamine dioxygenase from the deep-sea mussel Bathymodiolus septemdierum
In invertebrates inhabiting hydrothermal vent areas, hypotaurine, a precursor of taurine, is thought to mitigate the toxicity of hydrogen sulfide in vent fluids. Information about hypotaurine synthesis pathways in invertebrates is limited, although two pathways, the cysteamine [2-aminoethanethiol (A...
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Published in: | Fisheries science 2023-05, Vol.89 (3), p.387-397 |
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Main Authors: | , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | In invertebrates inhabiting hydrothermal vent areas, hypotaurine, a precursor of taurine, is thought to mitigate the toxicity of hydrogen sulfide in vent fluids. Information about hypotaurine synthesis pathways in invertebrates is limited, although two pathways, the cysteamine [2-aminoethanethiol (AET)] pathway and the cysteine sulfinate (CSA) pathway are known in mammals. In this study, we cloned a cDNA encoding AET dioxygenase (ADO), the central enzyme of the AET pathway, from the vent mussel
Bathymodiolus septemdierum
. In the encoded protein (
Bs
ADO), functionally important residues, including metal-binding histidines, are conserved. In maximum likelihood phylogenetic analysis,
Bs
ADO clustered with ADOs of other invertebrates. By reverse transcription PCR,
BsADO
mRNA was detected in all tissues examined at similar levels, suggesting that its function is distinct from that of the CSA pathway, predominantly expressed in the gill.
Bs
ADO with a His tag, expressed in
Escherichia coli
in the presence of Fe
2+
, converted AET to hypotaurine, but
Bs
ADO expressed in the absence of iron exhibited lower activity.
Bs
ADO was active from pH 8 to 11, and from 0 °C to 37 °C, with a peak at 20 °C. This is the first functional characterization of
ADO
in marine invertebrates. |
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ISSN: | 0919-9268 1444-2906 |
DOI: | 10.1007/s12562-023-01674-w |