關鍵詞： X射線晶體學丨核糖體丨RNA
當翻譯被啟動時，只有核糖體的小亞單元結合到信使RNA （mRNA）上。一旦啟動密碼子被識別出來，通過沿著mRNA轉位或“掃描”，大亞單元便會與小亞單元結合重組一個完整的核糖體。Ivan Lomakin 和 Thomas Steitz解決了與“啟動因子tRNA”、mRNA以及啟動因子eIF1 和 eIF1A形成復合物的真核生物小核糖體亞單元的三個結構。這些結構有助于了解啟動因子的貢獻、mRNA被掃描的機制以及在核糖體P點上發生的相互作用。（生物谷Bioon.com）
生物谷推薦英文摘要：
The initiation of mammalian protein synthesis and mRNA scanning mechanism
Ivan B. Lomakin & Thomas A. Steitz
During translation initiation in eukaryotes, the small ribosomal subunit binds messenger RNA at the 5′ end and scans in the 5′ to 3′ direction to locate the initiation codon, form the 80S initiation complex and start protein synthesis. This simple, yet intricate, process is guided by multiple initiation factors. Here we determine the structures of three complexes of the small ribosomal subunit that represent distinct steps in mammalian translation initiation. These structures reveal the locations of eIF1, eIF1A, mRNA and initiator transfer RNA bound to the small ribosomal subunit and provide insights into the details of translation initiation specific to eukaryotes. Conformational changes associated with the captured functional states reveal the dynamics of the interactions in the P site of the ribosome. These results have functional implications for the mechanism of mRNA scanning
