Identification of a radical SAM enzyme involved in the synthesis of archaeosine.
Nat Chem Biol
; 15(12): 1148-1155, 2019 12.
Article
em En
| MEDLINE
| ID: mdl-31740832
ABSTRACT
Archaeosine (G+), 7-formamidino-7-deazaguanosine, is an archaea-specific modified nucleoside found at the 15th position of tRNAs. In Euryarchaeota, 7-cyano-7-deazaguanine (preQ0)-containing tRNA (q0N-tRNA), synthesized by archaeal tRNA-guanine transglycosylase (ArcTGT), has been believed to be converted to G+-containing tRNA (G+-tRNA) by the paralog of ArcTGT, ArcS. However, we found that several euryarchaeal ArcSs have lysine transfer activity to q0N-tRNA to form q0kN-tRNA, which has a preQ0 lysine adduct as a base. Through comparative genomics and biochemical experiments, we found that ArcS forms a robust complex with a radical S-adenosylmethionine (SAM) enzyme named RaSEA. The ArcS-RaSEA complex anaerobically converted q0N-tRNA to G+-tRNA in the presence of SAM and lysine via q0kN-tRNA. We propose that ArcS and RaSEA should be considered an archaeosine synthase α-subunit (lysine transferase) and ß-subunit (q0kN-tRNA lyase), respectively.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
S-Adenosilmetionina
/
Enzimas
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Guanosina
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article