1bkb
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(New page: 200px<br /><applet load="1bkb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bkb, resolution 1.75Å" /> '''INITIATION FACTOR 5A...)
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Revision as of 09:36, 20 November 2007
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INITIATION FACTOR 5A FROM ARCHEBACTERIUM PYROBACULUM AEROPHILUM
Overview
BACKGROUND: Translation initiation factor 5A (IF-5A) is reported to be, involved in the first step of peptide bond formation in translation, to be, involved in cell-cycle regulation and to be a cofactor for the Rev and Rex, transactivator proteins of human immunodeficiency virus-1 and T-cell, leukemia virus I, respectively. IF-5A contains an unusual amino acid, hypusine (N-epsilon-(4-aminobutyl-2-hydroxy)lysine), that is required for, its function. The first step in the post-translational modification of, lysine to hypusine is catalyzed by the enzyme deoxyhypusine synthase, the, structure of which has been published recently. RESULTS: IF-5A from the, archebacterium Pyrobaculum aerophilum has been heterologously expressed in, Escherichia coli with selenomethionine substitution. The crystal structure, of IF-5A has been determined by multiwavelength anomalous diffraction and, refined to 1.75 A. Unmodified P. aerophilum IF-5A is found to be a beta, structure with two domains and three separate hydrophobic cores., CONCLUSIONS: The lysine (Lys42) that is post-translationally modified by, deoxyhypusine synthase is found at one end of the IF-5A molecule in an, turn between beta strands beta4 and beta5; this lysine residue is freely, solvent accessible. The C-terminal domain is found to be homologous to the, cold-shock protein CspA of E. coli, which has a well characterized, RNA-binding fold, suggesting that IF-5A is involved in RNA binding.
About this Structure
1BKB is a Single protein structure of sequence from Pyrobaculum aerophilum. Full crystallographic information is available from OCA.
Reference
Structure of translation initiation factor 5A from Pyrobaculum aerophilum at 1.75 A resolution., Peat TS, Newman J, Waldo GS, Berendzen J, Terwilliger TC, Structure. 1998 Sep 15;6(9):1207-14. PMID:9753699
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