Abstract
The pathway is described for activation by Mg2+ of substrates for M1 RNA, the catalytic subunit of the RNase P from Escherichia coli. The dissociation constants are reported for binding of Mg2+ to the substrate and for the binding of the metal ion-substrate complex to the enzyme. The enzyme binds the substrate with the same affinity whether or not Mg2+ is already bound to the substate. However, only substrates with bound Mg2+ can make a productive ternary complex when combined with the enzyme. The presence of certain 2'-hydroxyl groups in the substrate is required to stabilize the binding of Mg2+ and, thereby, to increase the lifetime of the ternary complex. An energy profile for the reaction of M1 RNA with a small model substrate is presented and the role of Mg2+ bound to the substrate is discussed.
Original language | English (US) |
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Pages (from-to) | 750-756 |
Number of pages | 7 |
Journal | Journal of molecular biology |
Volume | 230 |
Issue number | 3 |
DOIs | |
State | Published - Apr 5 1993 |
Externally published | Yes |
Keywords
- Catalytic RNA
- Mg-binding site
- RNA-DNA substrates
- RNase P
- Substrate activation
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology