1g7s
X-RAY STRUCTURE OF TRANSLATION INITIATION FACTOR IF2/EIF5B COMPLEXED WITH GDP
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OverviewOverview
X-ray structures of the universal translation initiation factor IF2/eIF5B, have been determined in three states: free enzyme, inactive IF2/eIF5B.GDP, and active IF2/eIF5B.GTP. The "chalice-shaped" enzyme is a GTPase that, facilitates ribosomal subunit joining and Met-tRNA(i) binding to ribosomes, in all three kingdoms of life. The conserved core of IF2/eIF5B consists of, an N-terminal G domain (I) plus an EF-Tu-type beta barrel (II), followed, by a novel alpha/beta/alpha-sandwich (III) connected via an alpha helix to, a second EF-Tu-type beta barrel (IV). Structural comparisons reveal a, molecular lever, which amplifies a modest conformational change in the, Switch 2 region of the G domain induced by Mg(2+)/GTP binding over a, distance of 90 A from the G domain active center to domain IV. Mechanisms, of GTPase function and ribosome binding are discussed.
About this StructureAbout this Structure
1G7S is a Single protein structure of sequence from Methanothermobacter thermautotrophicus with GDP as ligand. Full crystallographic information is available from OCA.
ReferenceReference
X-Ray structures of the universal translation initiation factor IF2/eIF5B: conformational changes on GDP and GTP binding., Roll-Mecak A, Cao C, Dever TE, Burley SK, Cell. 2000 Nov 22;103(5):781-92. PMID:11114334
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