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