Talk abstracts

Talk on Friday 01:30-01:50pm submitted by Fei Liu

Coupling of ATP binding and hydrolysis to duplex unwinding by the DEAD-box protein Ded1p

Fei Liu (Department of Physics,Case Western Reserve University, Cleveland, OH), Huijue Jia (Department of Biochemistry, Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH), Eckhard Jankowsky (Department of Physics,Department of Biochemistry, Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH)

Abstract:
DEAD-box proteins rearrange RNA and RNP structures in an ATP-dependent fashion, but it is unknown how ATP binding and hydrolysis are coupled to the remodeling processes. Here we have analyzed the coupling of RNA duplex unwinding to ATP binding and hydrolysis by the DEAD-box protein Ded1p from Saccharomyces cerevisiae. We show that the actual strand separation during duplex unwinding requires only ATP binding but not actual hydrolysis. ATP hydrolysis is used to enable the enzyme to dissociate from the RNA substrate subsequent to the strand separation, which is important for substrate turnover. Our data show that no coupling exists between the energy released during ATP hydrolysis and strand separation by Ded1p. The findings explain mechanistic features of DEAD-box proteins that previously have been difficult to interpret.

Keywords: ATP hydrolysis, unwinding, DEAD-box