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Pathway of ATP utilization and duplex rRNA unwinding by the DEAD-box helicase, DbpA.

ABSTRACT: DEAD-box RNA helicase proteins use the energy of ATP hydrolysis to drive the unwinding of duplex RNA. However, the mechanism that couples ATP utilization to duplex RNA unwinding is unknown. We measured ATP utilization and duplex RNA unwinding by DbpA, a non-processive bacterial DEAD-box RNA helicase specifically activated by the peptidyl transferase center (PTC) of 23S rRNA. Consumption of a single ATP molecule is sufficient to unwind and displace an 8 base pair rRNA strand annealed to a 32 base pair PTC-RNA "mother strand" fragment. Strand displacement occurs after ATP binding and hydrolysis but before P(i) product release. P(i) release weakens binding to rRNA, thereby facilitating the release of the unwound rRNA mother strand and the recycling of DbpA for additional rounds of unwinding. This work explains how ATPase activity of DEAD-box helicases is linked to RNA unwinding.

SUBMITTER: Henn A

PROVIDER: S-EPMC2840157 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature

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Pathway of ATP utilization and duplex rRNA unwinding by the DEAD-box helicase, DbpA.

Henn Arnon A Cao Wenxiang W Licciardello Nicholas N Heitkamp Sara E SE Hackney David D DD De La Cruz Enrique M EM

Proceedings of the National Academy of Sciences of the United States of America 20100216 9

DEAD-box RNA helicase proteins use the energy of ATP hydrolysis to drive the unwinding of duplex RNA. However, the mechanism that couples ATP utilization to duplex RNA unwinding is unknown. We measured ATP utilization and duplex RNA unwinding by DbpA, a non-processive bacterial DEAD-box RNA helicase specifically activated by the peptidyl transferase center (PTC) of 23S rRNA. Consumption of a single ATP molecule is sufficient to unwind and displace an 8 base pair rRNA strand annealed to a 32 base ...[more]

PMID: 20160110

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