Contacts between mammalian mitochondrial translational initiation factor 3 and ribosomal proteins in the small subunit
Contacts between mammalian mitochondrial translational initiation factor 3 and ribosomal proteins in the small subunit
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DOI：
10.1016/j.bbapap.2011.09.013
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发表时间：
2011-12-01
影响因子：
3.2
通讯作者：
Spremulli, Linda L.
中科院分区：
文献类型：
--
作者：
Haque, Md. Emdadul;Koc, Hasan;Spremulli, Linda L.
哺乳动物线粒体翻译起始因子3(IF3，mt)与核糖体的小亚基结合，在蛋白质合成过程中取代大亚基。线粒体核糖体中大约一半的蛋白质在细菌中有同源物，其余的是线粒体独有的。为了获得位于IF3(Mt)结合位点附近的核糖体蛋白的信息，进行了交联性研究，然后用质谱仪鉴定了交联性蛋白。IF3(MT)与细菌核糖体蛋白S5、S9、S10和S18-2的哺乳动物线粒体同源物以及独特的线粒体核糖体蛋白MRPS29、MRPS32、MRPS36和PTCD3(Pet309)交链，后者现已被鉴定为小亚基核糖体蛋白。与细菌因子相比，IF3(Mt)在N-末端和C-末端都有延伸。缺少这些扩展的截断导数的交联会产生与全长IF3(MT)相同的命中，除了没有观察到与MRPS36的交叉链接。IF3由两个结构域组成，由一个灵活的连接子隔开。分离的N-结构域和C-结构域与一系列核糖体蛋白发生了交联性，特别是C-结构域携带连接物，与原核生物中没有的几种核糖体蛋白有显着的交联性。(C)2011爱思唯尔B.V.保留所有权利。
Mammalian mitochondrial translational initiation factor 3 (IF3(mt)) binds to the small subunit of the ribosome displacing the large subunit during the initiation of protein biosynthesis. About half of the proteins in mitochondrial ribosomes have homologs in bacteria while the remainder are unique to the mitochondrion. To obtain information on the ribosomal proteins located near the IF3(mt) binding site, cross-linking studies were carried out followed by identification of the cross-linked proteins by mass spectrometry. IF3(mt) cross-links to mammalian mitochondrial homologs of the bacterial ribosomal proteins S5, S9, S10, and S18-2 and to unique mitochondrial ribosomal proteins MRPS29, MRPS32, MRPS36 and PTCD3 (Pet309) which has now been identified as a small subunit ribosomal protein. IF3(mt) has extensions on both the N- and C-termini compared to the bacterial factors. Cross-linking of a truncated derivative lacking these extensions gives the same hits as the full length IF3(mt) except that no cross-links were observed to MRPS36. IF3 consists of two domains separated by a flexible linker. Cross-linking of the isolated N- and C-domains was observed to a range of ribosomal proteins particularly with the C-domain carrying the linker which showed significant cross-linking to several ribosomal proteins not found in prokaryotes. (C) 2011 Elsevier B.V. All rights reserved.