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PDBsum entry 2g2k
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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 eukaryotic initiation factor (eif) 5 reveals a fold common to several translation factors.
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Authors
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M.R.Conte,
G.Kelly,
J.Babon,
D.Sanfelice,
J.Youell,
S.J.Smerdon,
C.G.Proud.
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Ref.
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Biochemistry, 2006,
45,
4550-4558.
[DOI no: ]
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PubMed id
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Abstract
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Eukaryotic initiation factor 5 (eIF5) plays multiple roles in translation
initiation. Its N-terminal domain functions as a GTPase-activator protein (GAP)
for GTP bound to eIF2, while its C-terminal region nucleates the interactions
between multiple translation factors, including eIF1, which acts to inhibit GTP
hydrolysis or P(i) release, and the beta subunit of eIF2. These proteins and the
events in which they participate are critical for the accurate recognition of
the correct start codon during translation initiation. Here, we report the
three-dimensional solution structure of the N-terminal domain of human eIF5,
comprising two subdomains, both reminiscent of nucleic-acid-binding modules. The
N-terminal subdomain contains the "arginine finger" motif that is essential for
GAP function but which, unusually, resides in a partially disordered region of
the molecule. This implies that a conformational reordering of this portion of
eIF5 is likely to occur upon formation of a competent complex for GTP
hydrolysis, following the appropriate activation signal. Interestingly, the
N-terminal subdomain of eIF5 reveals an alpha/beta fold structurally similar to
both the archaeal orthologue of the beta subunit of eIF2 and, unexpectedly, to
eIF1. These results reveal a novel protein fold common to several factors
involved in related steps of translation initiation. The implications of these
observations are discussed in terms of the mechanism of translation initiation.
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