2g2k | pdb_00002g2k
NMR structure of an N-terminal fragment of the eukaryotic initiation factor 5 (eIF5)
Structural highlights
FunctionIF5_HUMAN Catalyzes the hydrolysis of GTP bound to the 40S ribosomal initiation complex (40S.mRNA.Met-tRNA[F].eIF-2.GTP) with the subsequent joining of a 60S ribosomal subunit resulting in the release of eIF-2 and the guanine nucleotide. The subsequent joining of a 60S ribosomal subunit results in the formation of a functional 80S initiation complex (80S.mRNA.Met-tRNA[F]). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEukaryotic 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. Structure of the eukaryotic initiation factor (eIF) 5 reveals a fold common to several translation factors.,Conte MR, Kelly G, Babon J, Sanfelice D, Youell J, Smerdon SJ, Proud CG Biochemistry. 2006 Apr 11;45(14):4550-8. PMID:16584190[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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