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Disulfide bond formation is not involved in cap‐binding activity of Xenopus translation initiation factor eIF‐4E
Author(s) -
Wakiyama Motoaki,
Sakai Nobuya,
Kojima Shuichi,
Miura Kin-ichiro
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00562-0
Subject(s) - xenopus , cysteine , gtp' , biochemistry , iodoacetamide , chemistry , mutagenesis , serine , affinity chromatography , mutant , biology , microbiology and biotechnology , enzyme , gene
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(m 7 GTP)‐affinity column chromatography. Even the mutant protein containing no cysteine showed an affinity for m 7 GTP. 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.