Crystal structure of yeast initiation factor 4A, a DEAD-box RNA helicase

摘要: The eukaryotic translation initiation factor 4A (eIF4A) is a member of the DEA(D/H)-box RNA helicase family, a diverse group of proteins that couples an ATPase activity to binding and unwinding. Previous work has provided structure amino-terminal, ATP-binding domain eIF4A. Extending those results, we have solved carboxyl-terminal eIF4A with data to 1.75 A resolution; it parallel α-β topology that superimposes, minor variations, on structures conserved motifs equivalent in other, distantly related helicases. Using 2.8 resolution molecular replacement the refined model domain, completed full-length eIF4A; “dumbbell” structure consisting two compact domains connected by extended linker. By using other helicases as template, compact can be modeled for suggest ( i ) motif IV binds RNA; ii ) Arg-298, which is conserved family but absent from many helicases, also iii V VI “link” amino-terminal through interactions ATP DEA(D/H) motif, providing mechanism coupling hydrolysis with conformational changes modulate binding.