1q0u
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(New page: 200px<br /><applet load="1q0u" size="450" color="white" frame="true" align="right" spinBox="true" caption="1q0u, resolution 1.85Å" /> '''Crystal Structure of...)
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Revision as of 01:14, 25 November 2007
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Crystal Structure of the BstDEAD N-terminal Domain
Overview
Most cellular processes requiring RNA structure rearrangement necessitate, the action of Asp-Glu-Ala-Asp (DEAD) proteins. Members of the family, named originally for the conserved DEAD amino acid sequence, are thought, to disrupt RNA structure and facilitate its rearrangement by unwinding, short stretches of duplex RNA. BstDEAD is a novel 436 amino acid, representative of the DEAD protein family from Bacillus stearothermophilus, that contains all eight conserved motifs found in DEAD proteins and is, homologous with other members of the family. Here, we describe the 1.85 A, resolution structure of the N-terminal domain (residues 1-211) of BstDEAD, (BstDEAD-NT). Similar to the corresponding domains of related helicases, BstDEAD-NT adopts a parallel alpha/beta structure with RecA-like topology., In general, the conserved motifs superimpose on closely related DEAD, proteins and on more distantly related helicases such as RecA. This, affirms the current belief that the core helicase domains, responsible for, mechanistic activity, are structurally similar in DEAD proteins. In, contrast, however, the so-called Walker A P-loop, which binds the beta-, and gamma-phosphates of ATP, adopts a rarely seen "closed" conformation, that would sterically block ATP binding. The closed conformation may be, indicative of a general regulatory feature among DEAD proteins (and RNA, helicases) that differs from that used by DNA helicases. BstDEAD also, contains a unique extension of approximately 60 residues at the C terminus, that is highly basic, suggesting that it might bind nucleic acids and, in, so doing, confer specificity to the helicase activity of the core region.
About this Structure
1Q0U is a Single protein structure of sequence from Geobacillus stearothermophilus. Full crystallographic information is available from OCA.
Reference
Crystal structure of the BstDEAD N-terminal domain: a novel DEAD protein from Bacillus stearothermophilus., Carmel AB, Matthews BW, RNA. 2004 Jan;10(1):66-74. PMID:14681586
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