Disulfide bond formation is not involved in cap‐binding activity of Xenopus translation initiation factor eIF‐4E

FEBS Letters

Sakai, Nobuya¹  Miura, Kin-ichiro¹  Kojima, Shuichi¹  Wakiyama, Motoaki¹ 

[1] Institute for Biomolecular Science, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171, Japan

关键词: Translation initiation factor;    eIF-4E;    Xenopus laevis;    Site-directed mutagenesis;    Disulfide bond;   

DOI  :  10.1016/S0014-5793(97)00562-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The eukaryotic initiation factor eIF-4E from Xenopus laevis was expressed in Escherichia coli and refolded in an active form. To define the cysteine residues forming a disulfide bond in Xenopus eIF-4E, each of the 3 cysteine residues was changed to serine by site-directed mutagenesis. Cap-binding activities of the mutant proteins were evaluated by 7-methyl-GTP(m⁷GTP)-affinity column chromatography. Even the mutant protein containing no cysteine showed an affinity for m⁷GTP. From the above results and the estimation of the sulfhydryl groups by Ellman's assay method, we concluded that a disulfide bond is not involved in the active Xenopus eIF-4E.

【 授权许可】

Unknown