tailieunhanh - Báo cáo khoa học: Mutational analyses of human eIF5A-1 – identification of amino acid residues critical for eIF5A activity and hypusine modification

The eukaryotic translation initiation factor 5A (eIF5A) is the only protein that contains hypusine [N e -(4-amino-2-hydroxybutyl)lysine], which is required for its activity. Hypusine is formed by post-translational modifica-tion of one specific lysine (Lys50 for human eIF5A) by deoxyhypusine syn-thase and deoxyhypusine hydroxylase. | ễFEBS Journal Mutational analyses of human eIF5A-1 - identification of amino acid residues critical for eIF5A activity and hypusine modification Veridiana S. P. Cano1 2 Geoung A. Jeon1 t Hans E. Johansson3 C. Allen Henderson4 Jong-Hwan Park1 Sandro R. Valentini2 John W. B. Hershey4 and Myung Hee Park1 1 Oraland PharyngealCancer Branch National institute of Dentaland CraniofacialResearch National institutes of Health Bethesda MD USA 2 Department of BiologicalSciences Schoolof PharmaceuticalSciences Sao Paulo State University Brazil 3 Biosearch Technologies Inc. Novato CA USA 4 Department of Biochemistry and Molecular Medicine Schoolof Medicine University of California Davis CA USA Keywords deoxyhypusine synthase eIF5A hypusine post-translationalmodification translation initiation Correspondence M. H. Park Bldg 30 Room 211 OPCB NIDCR NIH Bethesda MD 20892-4340 USA Fax 1301-402-0823 Tel 1301-496-5056 E-mail mhpark@ tPresent address Department of Microbiology Korea University College of Medicine Seoul Korea These authors contributed equally to this work Received 11 July 2007 revised 5 October 2007 accepted 30 October 2007 doi The eukaryotic translation initiation factor 5A eIF5A is the only protein that contains hypusine Ne- 4-amino-2-hydroxybutyl lysine which is required for its activity. Hypusine is formed by post-translational modification of one specific lysine Lys50 for human eIF5A by deoxyhypusine synthase and deoxyhypusine hydroxylase. To investigate the features of eIF5A required for its activity we generated 49 mutations in human eIF5A-1 with a single amino acid substitution at the highly conserved residues or with N-terminal or C-terminal truncations and tested mutant proteins in complementing the growth of a Saccharomyces cerevisiae eIF5A null strain. Growth-supporting activity was abolished in only a few mutant eIF5As K47D G49A K50A K50D K50I K50R G52A and K55A with substitutions at or near the hypusine modification .