title: Dimerization of the yeast eukaryotic translation initiation factor 5A requires hypusine and is RNA dependent.
abstract: Post-translational modification of the highly conserved K51 residue of the Saccharomyces cerevisiae eukaryotic translation initiation factor 5A (eIF5A) to form hypusine, is essential for its many functions including the binding of specific mRNAs. We characterized hypusinated yeast eIF5A by size-exclusion chromatography and native PAGE, showing that the protein exists as a homodimer. A K51R mutant, which was not functional in vivo eluted as a monomer and inhibition of hypusination abolished dimerization. Furthermore, treatment of dimeric eIF5A with RNase A resulted in disruption of the dimer, leading us to conclude that RNA binding is also required for dimerization of eIF5A. We present a model of dimerization, based on the Neurospora crassa structural analogue, HEX-1.
authors.affiliation: Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, South Africa.
authors.forename: Petra M
authors.initials: PM
authors.lastname: Gentz
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Blatch
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Dorrington
mesh_terms: D018360:Crystallography, X-Ray; D008239:Lysine / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009492:Neurospora crassa / Q000235:genetics / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D008239:Lysine; D010448:Peptide Initiation Factors; D012331:RNA, Fungal; D016601:RNA-Binding Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C100028:hypusine