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PDBsum entry 1k8b
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure of the beta subunit of translation initiation factor 2 from the archaeon methanococcus jannaschii: a representative of the eif2beta/eif5 family of proteins.
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Authors
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S.Cho,
D.W.Hoffman.
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Ref.
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Biochemistry, 2002,
41,
5730-5742.
[DOI no: ]
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PubMed id
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Abstract
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The beta subunit of archaeal translation initiation factor 2 (aIF2beta) is a
representative of a family of proteins whose members include the beta subunit of
eukaryotic translation initiation factor 2 (eIF2beta) and the N-terminal domain
within translation initiation factor 5 (eIF5); no members of this family of
proteins have been structurally characterized up to this time. In the work
presented here, aIF2beta from Methanococcus jannaschii was expressed in
Escherichia coli, purified, and analyzed using multidimensional NMR methods. The
aIF2beta was found to contain two independent structural domains. The N-terminal
domain contains a four-stranded antiparallel beta sheet and two alpha helices,
and is structurally similar to the DNA-binding domain of a yeast heat shock
transcription factor and a domain within ribosomal protein S4. This structural
similarity was an unanticipated result, since no significant homology was
detected at the level of primary sequence. The C-terminal domain of aIF2beta
contains a zinc-binding motif of three antiparallel beta strands, with four
conserved cysteines arranged as two CXXC units separated by 17 residues.
Conserved residues on the surface of each domain that are likely candidates for
direct interaction with other components of the translational apparatus were
identified. The significant primary sequence homology between archaeal aIF2beta
and the eukaryotic eIF2beta and eIF5, when combined with the structural results
in the work presented here, permitted structural features to be predicted for
these latter two eukaryotic proteins.
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