A SPECTROSCOPIC STUDY OF THE BINDING OF M7GTP AND M7GPPPG TO HUMAN PROTEIN-SYNTHESIS INITIATION FACTOR-4E
A SPECTROSCOPIC STUDY OF THE BINDING OF M7GTP AND M7GPPPG TO HUMAN PROTEIN-SYNTHESIS INITIATION FACTOR-4E
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DOI：
10.1021/bi00446a017
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发表时间：
1989-10-03
期刊：
影响因子：
2.9
通讯作者：
GOSS, DJ
中科院分区：
文献类型：
--
作者：
CARBERRY, SE;RHOADS, RE;GOSS, DJ
7-甲基鸟苷帽类似物m7GTP和m7GpppG与人红细胞eIF-4E的结合随pH、温度和离子强度的变化而变化。从m7GTP和m7GpppG与eIF-4E的pH依赖结合出发，提出了一个描述CaP-eIF-4E相互作用性质的新模型。结合的热力学数值和离子强度依赖于以疏水为主的结合部位。荧光和圆二色谱数据表明，在某种掩埋的环境中，色氨酸残基可能参与了与帽子的碱基堆积作用。这里提出的模型证实了早先的提议[Rhoads等人。(1983)生物化学22,6084-6088]认为帽子的烯状互变异构体是相互作用的首选，并进一步提出相互作用是与质子化氨基酸残基，如组氨酸，而与芳香氨基酸，如色氨酸堆积。
The binding of analogues of the 7-methylguanosine-containing cap, m7GTP and m7GpppG, to eIF-4E from human erythrocytes as a function of pH, temperature, and ionic strength is described. From the pH-dependent binding of m7GTP and m7GpppG to eIF-4E, a new model describing the nature of the cap-eIF-4E interaction is proposed. The thermodynamic values and ionic strength dependence of binding are consistent with a binding site which is primarily hydrophobic. Fluorescence and circular dichroism data indicate that tryptophan residues may be involved in base-stacking interactions with the cap in a somewhat buried environment. The model presented here confirms the earlier proposal [Rhoads et al. (1983) Biochemistry 22, 6084-6088] that the enolate tautomer of the cap is preferred for interaction and further proposes that the interaction is with a protonated amino acid residue, such as histidine, while stacking with an aromatic amino acid, such as tryptophan.