Positioning of mRNA codons with respect to 18S rRNA at the P and E sites of human ribosome
Positioning of mRNA codons with respect to 18S rRNA at the P and E sites of human ribosome
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DOI：
10.1016/s0167-4781(03)00072-1
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发表时间：
2003-05-13
期刊：
影响因子：
--
通讯作者：
Karpova, G
中科院分区：
文献类型：
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作者：
Demeshkina, N;Laletina, E;Karpova, G
通过与mRNA类似物、在第二个或第三个尿嘧啶上携带全氟苯基叠氮化物基团的六核糖核苷酸UUUGUU（包含Phe和瓦尔密码子）的衍生物和在鸟嘌呤残基上具有类似基团的十二核糖核苷酸UUAGUAUUAUU的衍生物交联，研究了E位点和P位点结合密码子的每个核苷酸相对于人核糖体上的18 S rRNA的定位。修饰的核苷酸在从-3到+3的任何mRNA位置（位置+ I对应于P位点结合密码子的5'核苷酸）的位置通过同源tRNA来调节。- I至+3位的修饰尿苷与18 S rRNA的核苷酸G1207交联，当其在- 2位时与核苷酸G961交联。与核苷酸G1207交联的修饰鸟苷，如果其位于mRNA的位置-3。这些数据表明，18 S rRNA的核苷酸G961仅靠近mRNA的位置-3和-2，而G1207位于-3至+3的位置附近。后者表明，在P和E位点结合的密码子之间存在一个急转弯，使18 S rRNA的核苷酸G1207接近这些密码子的每个核苷酸。这与细菌核糖体上的X射线晶体学数据很好地相关，表明在靠近16 S rRNA的保守核苷酸G926（对应于18 S rRNA中的G 1207）的螺旋23 b（包含16 S rRNA的保守核苷酸693（精确地对应于18 S rRNA的G961））的P位点和E位点结合密码子之间存在急转弯。(C)2003 Elsevier Science BY，保留所有权利。
Positioning of each nucleotide of the E site and the P site bound codons with respect to the 18S rRNA on the human ribosome was studied by cross-linking with mRNA analogs, derivatives of the hexaribonucleotide UUUGUU (comprising Phe and Val codons) that carried a perfluorophenylazide group on the second or the third uracil, and a derivative of the dodecaribonucleotide UUAGUAUUUAUU with a similar group on the guanine residue. The location of the modified nucleotides at any mRNA position from - 3 to + 3 (position + I corresponds to the 5' nucleotide of the P site bound codon) was adjusted by the cognate tRNAs. A modified uridine at positions from - I to + 3 cross-linked to nucleotide G1207 of the 18S rRNA, and to nucleotide G961 when it was in position - 2. A modified guanosine crosslinked to nucleotide G1207 if it was in position - 3 of the mRNA. These data indicate that nucleotide G961 of the 18S rRNA is close only to mRNA positions - 3 and - 2, while G1207 is in the vicinity of positions from - 3 to + 3. The latter suggests that there is a sharp turn between the P and E site bound codons that brings nucleotide G1207 of the 18S rRNA close to each nucleotide of these codons. This correlates well with X-ray crystallographic data on bacterial ribosomes, indicating existence of a sharp turn between the P site and E site bound codons near a conserved nucleotide G926 of the 16S rRNA (corresponding to G 1207 in 18S rRNA) close to helix 23b containing the conserved nucleotide 693 of the 16S rRNA (corresponding exactly to G961 of the 18S rRNA). (C) 2003 Elsevier Science BY, All rights reserved.