Crystallographic structure of the amino terminal domain of yeast initiation factor 4A, a representative DEAD-box RNA helicase.
The eukaryotic translation initiation factor 4A (elF4A) is a representative of the DEAD-box RNA helicase protein family. We have solved the crystallographic structure of the amino-terminal domain (residues 1-223) of yeast elF4A. The domain is built around a core scaffold, a parallel alpha-beta motif with five beta strands, that is found in other RNA and DNA helicases, as well as in the RecA protein. The amino acid sequence motifs that are conserved within the helicase family are localized to the beta strand-->alpha helix junctions within the core. The core of the amino terminal domain of elF4A is amplified with additional structural elements that differ from those of other helicases. The phosphate binding loop (the Walker A motif) is in an unusual closed conformation. The crystallographic structure reveals specific interactions between amino acid residues of the phosphate binding loop, the DEAD motif, and the SAT motif, whose alteration is known to impair coupling between the ATPase cycle and the RNA unwinding activity of elF4A.
Johnson
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Department of Structural Biology, Stanford University School of Medicine, California 94305-5400, USA.
McKay
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DB
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray / Q000379:methods; D053487:DEAD-box RNA Helicases; D039601:Eukaryotic Initiation Factor-4A; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010448:Peptide Initiation Factors / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D020365:RNA Helicases / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D039601:Eukaryotic Initiation Factor-4A; C490285:DBP8 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases