tailieunhanh - Báo cáo khoa học: Structural modeling and mutational analysis of yeast eukaryotic translation initiation factor 5A reveal new critical residues and reinforce its involvement in protein synthesis

Eukaryotic translation initiation factor 5A (eIF5A) is a protein that is highly conserved and essential for cell viability. This factor is the only pro-tein known to contain the unique and essential amino acid residue hypu-sine. This work focused on the structural and functional characterization ofSaccharomyces cerevisiaeeIF5A. | ễFEBS Journal Structural modeling and mutational analysis of yeast eukaryotic translation initiation factor 5A reveal new critical residues and reinforce its involvement in protein synthesis Camila A. O. Dias1 Veridiana S. P. Cano1 Suzana M. Rangel1 Luciano H. Apponi1 Mariana C. Frigieri1 Joao R. C. Muniz3 Wanius Garcia3 Myung H. Park2 Richard C. Garratt3 Cleslei F. Zanelli1 and Sandro R. Valentini1 1 Department of BiologicalSciences Schoolof PharmaceuticalSciences Sao Paulo State University - UNESP Araraquara Brazil 2 Oraland PharyngealCancer Branch NationalInstitute of Dentaland CraniofacialResearch NationalInstitutes of Health Bethesda MD USA 3 Center for StructuralMolecular Biotechnology Departament of Physics and Informatics Institute of Physics of Sao Carlos University of Sao Paulo Brazil Keywords eIF5A hypusine mutationalanalysis structuralmodeling translation Correspondence S. R. Valentini Faculdade de Ciencias Farmaceuticas - UNESP Rodovia Araraquara-Jau km 1 Araraquara Sao Paulo 14801 902 Brazil Fax 55 16 3301 6940 Tel 55 16 3301 6954 E-mail valentsr@ Received 7 November 2007 revised 11 February 2008 accepted 19 February 2008 doi Eukaryotic translation initiation factor 5A eIF5A is a protein that is highly conserved and essential for cell viability. This factor is the only protein known to contain the unique and essential amino acid residue hypu-sine. This work focused on the structural and functional characterization of Saccharomyces cerevisiae eIF5A. The tertiary structure of yeast eIF5A was modeled based on the structure of its Leishmania mexicana homologue and this model was used to predict the structural localization of new site-directed and randomly generated mutations. Most of the 40 new mutants exhibited phenotypes that resulted from eIF-5A protein-folding defects. Our data provided evidence that the C-terminal a-helix present in yeast eIF5A is an essential structural element whereas the eIF5A .