| Accepted Name |
|---|
| DEAD-box RNA helicase
|
| Reaction catalysed |
|---|
| ATP + H2O + wound RNA = ADP + phosphate + unwound RNA |
| Comment(s) |
|---|
- RNA helicases, which participate in nearly all aspects of RNA
metabolism, utilize the energy from ATP hydrolysis to unwind RNA.
- The engine core of helicases is usually made of a pair of RecA-like
domains that form an NTP binding cleft at their interface.
- Changes in the chemical state of the NTP binding cleft (binding of
the NTP or its hydrolysis products) alter the relative positions of
the RecA-like domains and nucleic acid-binding domains, creating
structural motions that disrupt the pairing of the nucleic acid,
causing separation and unwinding.
- While most RNA helicases utilize a mechanism known as canonical
duplex unwinding and translocate along the RNA (cf. EC 5.6.2.5 and
EC 5.6.2.6), DEAD-box RNA helicases differ by unwinding RNA via the
local strand separation mechanism, which does not involve
translocation.
- These helicases load directly on the duplex region, aided by single
stranded or structured nucleic acid regions.
- Upon loading, the DEAD-box protein locally opens the duplex strands.
This step requires binding of ATP, which is not hydrolyzed.
- The local helix opening causes the remaining basepairs to dissociate
without further action from the enzyme.
- Unwinding occurs without apparent polarity, and is limited to
relatively short distances.
- ATP hydrolysis is required for release of the DEAD-box protein from
the RNA.
- The name originates from the sequence D-E-A-D, which is found in
Motif II of these proteins.
|
| Cross-references |
|---|
| BRENDA | 5.6.2.7 |
| EC2PDB | 5.6.2.7 |
| ExplorEnz | 5.6.2.7 |
| KEGG Ligand Database for Enzyme Nomenclature | 5.6.2.7 |
| IUBMB Enzyme Nomenclature | 5.6.2.7 |
| MEDLINE | Find literature relating to 5.6.2.7 |
| MetaCyc | 5.6.2.7 |
| Rhea expert-curated reactions | 5.6.2.7 |
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