Mutations in the S4–H2 loop of eIF4E which increase the affinity for m7GTP

FEBS Letters

Gernert, Kim M¹  Hagedorn, Curt H³  Friedland, Diana E²  Goss, Dixie J²  De Staercke, Christine³  Spivak-Kroizman, Taly³ 

[1] Biomolecular Computing Resource and Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA;Department of Chemistry, Hunter College of the City University of New York, New York, NY 10021, USA;Departments of Medicine, Genetics Program of the Winship Cancer Center, and the Program for Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, 165 Michael Street, Room 201, Atlanta, GA 30322, USA

关键词: RNA binding protein;    Eukaryotic initiation factor 4E;    mRNA cap;    m7GTP;    Translation;    eIF4E;    eukaryotic initiation factor 4E;    eIF4G;    eukaryotic initiation factor 4G;    also called p220 or eIF4γ;    PHAS-I;    phosphorylated heat- and acid-stable protein regulated by insulin;    also called 4E binding protein 1 (4E-BP1);    8-N3GTP;    8-azidoguanosine 5′-triphosphate;   

DOI  :  10.1016/S0014-5793(02)02445-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Eukaryotic initiation factor 4E (eIF4E) binds the 5′-cap of eukaryotic mRNAs and overexpression of eIF4E in epithelial cell cancers correlates with the metastases/tissue invasion phenotype. Photolabeling of eIF4E with [γ-³²P]8-azidoguanosine 5′-triphosphate (8-N₃GTP) demonstrated cross-linking at Lys-119 in the S4–H2 loop which is distant from the m⁷GTP binding site [Marcotrigiano et al. (1997) Cell 89, 951–961; Friedland et al. (1997) Protein Sci. 6, 125–131]. Modeling studies indicate that 8-N₃GTP cross-linked with Lys-119 because it binds a site that is occupied by the second nucleotide of a bound mRNA. Mutagenesis of the S4–H2 loop produced proteins with a 5–10-fold higher affinity for m⁷GTP than wild-type eIF4E. These mutants of eIF4E may have uses in selectively purifying mRNAs with intact 5′-ends or in determining how the promyelocytic leukemia protein decreases the affinity of eIF4E for mRNA caps.

【 授权许可】

Unknown