Determination of the folding topology of the SL1 RNA from Caenorhabditis elegans by multidimensional heteronuclear NMR.
Determination of the folding topology of the SL1 RNA from Caenorhabditis elegans by multidimensional heteronuclear NMR.
复制标题
通过多维异核 NMR 测定秀丽隐杆线虫 SL1 RNA 的折叠拓扑。
DOI：
10.1006/jmbi.1995.0499
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Patel,DJ
中科院分区：
文献类型：
--
作者：
Greenbaum,NL;Radhakrishnan,I;Hirsh,D;Patel,DJ
The process oftrans-splicing involves the transfer of a short spliced leader (SL) RNA sequence to a consensus acceptor site on a separate pre-mRNA transcript. In this study, the first stem loop of the SL1 RNA from the nematodeCaenorhabditis eleganswas examined by homonuclear and heteronuclear NMR. Results of enzymatic cleavage patterns established that the first 36 nucleotides (which includes the splice site and a complementary base-paired region surrounding a nine-nucleotide hairpin loop) remain structurally independent of the rest of the 100-nucleotide full-length transcript. A comparison of exchangeable and non-exchangeable proton chemical shifts in the region of the splice site and loop between the native sequence and a modified 26-nucleotide fragment from which an asymmetric internal loop had been deleted was made. There was no significant difference between the resonance locations of the equivalent protons in the two molecules, establishing that there was no tertiary interaction between the hairpin and internal loops. Full chemical shift assignments of1H,13C, and15N chemical shifts were obtained for the modified fragment by multidimensional homonuclear and heteronuclear NMR spectroscopy. The stem adopts anA-form helix typical of RNA. TheA-type helical conformation of the stem appears to continue for the first three nucleotides of the 5′ side of the loop, followed by a guanosine residue in asynconformation about the glycosidic bond. Base stacking is not seen on the 3′ side of the loop. There was no evidence for formation of Watson-Crick base-pairs within the loop, but several long distance NOEs indicated cross-loop contacts, indicative of a structured loop. The final loop residues, an adenine which is conserved among all known nematode SL RNA sequences, adopts an extrahelical conformation.
