Crystal Structures of Two Sm Protein Complexes and Their Implications for the Assembly of the Spliceosomal snRNPs

Autor: Veronica A. Raker, Johanna M. Avis, Reinhard Lührmann, C. Kambach, Robert I. M. Young, Kiyoshi Nagai, Jade Li, Eric de La Fortelle, S. Walke
Rok vydání: 1999
Předmět:
Zdroj: Cell. 96(3):375-387
ISSN: 0092-8674
DOI: 10.1016/s0092-8674(00)80550-4
Popis: The U1, U2, U4/U6, and U5 small nuclear ribonucleoprotein particles (snRNPs) involved in pre-mRNA splicing contain seven Sm proteins (B/B′, D1, D2, D3, E, F, and G) in common, which assemble around the Sm site present in four of the major spliceosomal small nuclear RNAs (snRNAs). These proteins share a common sequence motif in two segments, Sm1 and Sm2, separated by a short variable linker. Crystal structures of two Sm protein complexes, D3B and D1D2, show that these proteins have a common fold containing an N-terminal helix followed by a strongly bent five-stranded antiparallel β sheet, and the D1D2 and D3B dimers superpose closely in their core regions, including the dimer interfaces. The crystal structures suggest that the seven Sm proteins could form a closed ring and the snRNAs may be bound in the positively charged central hole.
Databáze: OpenAIRE