ID   5.6.2.6
DE   RNA 3'-5' helicase.
CA   n ATP + n H2O + wound RNA = n ADP + n 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   -!- Most RNA helicases utilize a mechanism known as canonical duplex
CC       unwinding, in which the helicase binds to a single stranded region
CC       adjacent to the duplex and then translocates along the bound strand
CC       with defined directionality, displacing the complementary strand.
CC   -!- Most of these helicases proceed 3' to 5' (type A polarity), but some
CC       proceed 5' to 3' (type B polarity - cf. EC 5.6.2.5), and some are
CC       able to catalyze unwinding in either direction.
CC   -!- Most canonically operating helicases require substrates with single
CC       stranded regions in a defined orientation (polarity) with respect to
CC       the duplex.
CC   -!- A different class of RNA helicases, EC 5.6.2.7, use a different
CC       mechanism and unwind short stretches of RNA with no translocation.
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