真核生物翻译起始因子4E（eIF4E）的S4-H2环中的突变会增加其对m7GTP的亲和力。
Mutations in the S4-H2 loop of eIF4E which increase the affinity for m7GTP.
作者信息
Spivak-Kroizman Taly, Friedland Diana E, De Staercke Christine, Gernert Kim M, Goss Dixie J, Hagedorn Curt H
机构信息
Department of Medicine, Genetics Program of the Winship Cancer Center, Emory University School of Medicine, 165 Michael Street, Room 201, Atlanta, GA 30322, USA.
出版信息
FEBS Lett. 2002 Apr 10;516(1-3):9-14. doi: 10.1016/s0014-5793(02)02445-6.
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 [gamma-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.
真核生物起始因子4E（eIF4E）与真核生物mRNA的5'-帽结合，上皮细胞癌中eIF4E的过表达与转移/组织侵袭表型相关。用[γ-32P]8-叠氮鸟苷5'-三磷酸（8-N3GTP）对eIF4E进行光标记，结果表明在S4-H2环的赖氨酸-119处发生了交联，该位点距离m7GTP结合位点较远[马尔科特里贾诺等人（1997年）《细胞》89卷，951 - 961页；弗里德兰德等人（1997年）《蛋白质科学》6卷，125 - 131页]。建模研究表明，8-N3GTP与赖氨酸-119交联是因为它结合了一个被结合mRNA的第二个核苷酸占据的位点。S4-H2环的诱变产生了对m7GTP的亲和力比野生型eIF4E高5 - 10倍的蛋白质。这些eIF4E突变体可用于选择性纯化具有完整5'-末端的mRNA，或用于确定早幼粒细胞白血病蛋白如何降低eIF4E对mRNA帽的亲和力。
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