Adenosine 5′-O-(3-thio)triphosphate (ATPγS) is a substrate for the nucleotide hydrolysis and RNA unwinding activities of eukaryotic translation initiation factor eIF4A
抄録
<jats:p>Whereas ATPγS is often considered a nonhydrolyzable substrate for ATPases, we present evidence that ATPγS is a good substrate for the RNA-stimulated nucleotide hydrolysis and RNA unwinding activities of eIF4A. In the presence of saturating single-stranded poly(U) RNA, eIF4A hydrolyzes ATPγS•Mg and ATP•Mg with similar steady-state parameters (<jats:italic>K</jats:italic><jats:sub>M</jats:sub><jats:sup>NTP•Mg</jats:sup> = 66 and 58 μM and <jats:italic>k</jats:italic><jats:sub>cat</jats:sub> = 1.0 and 0.97 min<jats:sup>−1</jats:sup>, respectively). ATPγS•Mg also supports catalysis of RNA unwinding within 10-fold of the rate supported by ATP•Mg. The identical steady-state rate parameters, in comparison with the expected difference in the intrinsic rate of hydrolysis for ATP and ATPγS, suggest a nonchemical rate-limiting step for nucleotide hydrolysis. These results raise caution concerning the assumption that ATPγS is a nonhydrolyzable ATP analog and underscore the utility of thio-substituted NTPs as mechanistic probes.</jats:p>
収録刊行物
-
- RNA
-
RNA 9 (10), 1180-1187, 2003-09-16
Cold Spring Harbor Laboratory
- Tweet
キーワード
詳細情報 詳細情報について
-
- CRID
- 1360011144398522880
-
- NII論文ID
- 30022824805
-
- ISSN
- 14699001
- 13558382
- http://id.crossref.org/issn/13558382
-
- データソース種別
-
- Crossref
- CiNii Articles