title: Structural basis of pre-mRNA splicing.
abstract: Splicing of precursor messenger RNA is performed by the spliceosome. In the cryogenic electron microscopy structure of the yeast spliceosome, U5 small nuclear ribonucleoprotein acts as a central scaffold onto which U6 and U2 small nuclear RNAs (snRNAs) are intertwined to form a catalytic center next to Loop I of U5 snRNA. Magnesium ions are coordinated by conserved nucleotides in U6 snRNA. The intron lariat is held in place through base-pairing interactions with both U2 and U6 snRNAs, leaving the variable-length middle portion on the solvent-accessible surface of the catalytic center. The protein components of the spliceosome anchor both 5' and 3' ends of the U2 and U6 snRNAs away from the active site, direct the RNA sequences, and allow sufficient flexibility between the ends and the catalytic center. Thus, the spliceosome is in essence a protein-directed ribozyme, with the protein components essential for the delivery of critical RNA molecules into close proximity of one another at the right time for the splicing reaction.
authors: Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Jing
authors: J
authors: Hang
authors: Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Ruixue
authors: R
authors: Wan
authors: Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors: Chuangye
authors: C
authors: Yan
authors: Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China. shi-lab@tsinghua.edu.cn.
authors: Yigong
authors: Y
authors: Shi
mesh_terms: D020134:Catalytic Domain; D005091:Exons; D007438:Introns; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D012322:RNA Precursors / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012342:RNA, Small Nuclear / Q000737:chemistry; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000737:chemistry; D017381:Spliceosomes / Q000737:chemistry*
chemical_list: D012322:RNA Precursors; D012333:RNA, Messenger; D012342:RNA, Small Nuclear; D017415:Ribonucleoprotein, U5 Small Nuclear; C405484:U2 small nuclear RNA; C405485:U5 small nuclear RNA