联系方式:400-990-3999 / 邮箱:sales@xiyashiji.com
西亚试剂 —— 品质可靠,值得信赖
Peter S. Shen1, Joseph Park2, Yidan Qin8,9, Xueming Li7,*, Krishna Parsawar10, Matthew H. Larson3,4,5,6, James Cox1,10, Yifan Cheng7, Alan M. Lambowitz8,9, Jonathan S. Weissman3,4,5,6,†, Onn Brandman2,†, Adam Frost1,7,†
In Eukarya, stalled translation induces 40S dissociation and recruitment of the ribosome quality control complex (RQC) to the 60S subunit, which mediates nascent chain degradation. Here we report cryo–electron microscopy structures revealing that the RQC components Rqc2p (YPL009C/Tae2) and Ltn1p (YMR247C/Rkr1) bind to the 60S subunit at sites exposed after 40S dissociation, placing the Ltn1p RING (Really Interesting New Gene) domain near the exit channel and Rqc2p over the P-site transfer RNA (tRNA). We further demonstrate that Rqc2p recruits alanine- and threonine-charged tRNA to the A site and directs the elongation of nascent chains independently of mRNA or 40S subunits. Our work uncovers an unexpected mechanism of protein synthesis, in which a protein—not an mRNA—determines tRNA recruitment and the tagging of nascent chains with carboxy-terminal Ala and Thr extensions