The iscS gene is essential for the biosynthesis of 2-selenouridine in tRNA and the selenocysteine-containing formate dehydrogenase H
| Autor: | Hisaaki Mihara, Tatsuo Kurihara, Thressa C. Stadtman, Nobuyoshi Esaki, Umechiyo Tokumoto, Robert A. J. D. Kennedy, Gerard M. Lacourciere, Yasuhiro Takahashi, Shin-ichiro Kato |
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| Rok vydání: | 2002 |
| Předmět: |
inorganic chemicals
Thiouridine chemistry.chemical_element Formate dehydrogenase chemistry.chemical_compound Hydrogenase RNA Transfer Biosynthesis Multienzyme Complexes Organoselenium Compounds Escherichia coli Uridine chemistry.chemical_classification Multidisciplinary Selenocysteine Molybdopterin Biological Sciences Formate Dehydrogenases Carbon-Sulfur Lyases Enzyme chemistry Biochemistry Mutagenesis Transfer RNA Selenoprotein Selenium |
| Zdroj: | Proceedings of the National Academy of Sciences. 99:6679-6683 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.102176099 |
| Popis: | Three NifS-like proteins, IscS, CSD, and CsdB, from Escherichia coli catalyze the removal of sulfur and selenium from l -cysteine and l -selenocysteine, respectively, to form l -alanine. These enzymes are proposed to function as sulfur-delivery proteins for iron-sulfur cluster, thiamin, 4-thiouridine, biotin, and molybdopterin. Recently, it was reported that selenium mobilized from free selenocysteine is incorporated specifically into a selenoprotein and tRNA in vivo , supporting the involvement of the NifS-like proteins in selenium metabolism. We here report evidence that a strain lacking IscS is incapable of synthesizing 5-methylaminomethyl-2-selenouridine and its precursor 5-methylaminomethyl-2-thiouridine (mnm 5 s 2 U) in tRNA, suggesting that the sulfur atom released from l -cysteine by the action of IscS is incorporated into mnm 5 s 2 U. In contrast, neither CSD nor CsdB was essential for production of mnm 5 s 2 U and 5-methylaminomethyl-2-selenouridine. The lack of IscS also caused a significant loss of the selenium-containing polypeptide of formate dehydrogenase H. Together, these results suggest a dual function of IscS in sulfur and selenium metabolism. |
| Databáze: | OpenAIRE |
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