Position of eukaryotic translation initiation factor eIF1A on the 40S ribosomal subunit mapped by directed hydroxyl radical probing

被引：82

作者：

Yu, Yingpu ^{[2
]}

Marintchev, Assen ^{[1
]}

Kolupaeva, Victoria G. ^{[2
]}

Unbehaun, Anett ^{[2
]}

Veryasova, Tatyana ^{[2
]}

Lai, Shao-Chiang ^{[2
]}

Hong, Peng ^{[2
]}

Wagner, Gerhard ^{[3
]}

Hellen, Christopher U. T. ^{[2
]}

Pestova, Tatyana V. ^{[2
]}

机构：

[1] Boston Univ, Sch Med, Dept Physiol & Biophys, Boston, MA 02118 USA

[2] Suny Downstate Med Ctr, Dept Microbiol & Immunol, Brooklyn, NY 11203 USA

[3] Harvard Univ, Sch Med, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA

来源：

NUCLEIC ACIDS RESEARCH | 2009年 / 37卷 / 15期

基金：

美国国家卫生研究院;

关键词：

MESSENGER-RNA; CRYSTAL-STRUCTURE; FACTORS; 1A; COMPLEX; BINDING; CODON; RELEASE; SITE; HYDROLYSIS; SELECTION;

D O I：

10.1093/nar/gkp519

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The universally conserved eukaryotic initiation factor (eIF), eIF1A, plays multiple roles throughout initiation: it stimulates eIF2/GTP/Met-tRNA(i)(Met) attachment to 40S ribosomal subunits, scanning, start codon selection and subunit joining. Its bacterial ortholog IF1 consists of an oligonucleotide/oligosaccharide-binding (OB) domain, whereas eIF1A additionally contains a helical subdomain, N-terminal tail (NTT) and C-terminal tail (CTT). The NTT and CTT both enhance ribosomal recruitment of eIF2/GTP/Met-tRNA(i)(Met), but have opposite effects on the stringency of start codon selection: the CTT increases, whereas the NTT decreases it. Here, we determined the position of eIF1A on the 40S subunit by directed hydroxyl radical cleavage. eIF1A's OB domain binds in the A site, similar to IF1, whereas the helical subdomain contacts the head, forming a bridge over the mRNA channel. The NTT and CTT both thread under Met-tRNA(i)(Met) reaching into the P-site. The NTT threads closer to the mRNA channel. In the proposed model, the NTT does not clash with either mRNA or Met-tRNA(i)(Met), consistent with its suggested role in promoting the 'closed' conformation of ribosomal complexes upon start codon recognition. In contrast, eIF1A-CTT appears to interfere with the P-site tRNA-head interaction in the 'closed' complex and is likely ejected from the P-site upon start codon recognition.

引用

页码：5167 / 5182

页数：16