1I9X

CRYSTAL STRUCTURE OF BPS-U2 SNRNA DUPLEX

Summary for 1I9X

• Entry DOI: 10.2210/pdb1i9x/pdb
• Descriptor: 5'-R(*UP*AP*CP*UP*AP*AP*CP*GP*UP*AP*GP*UP*A)-3' (2 entities in total)
• Functional Keywords: pre-mrna splicing, bulged adenosine, three helix junction, rna
• Total number of polymer chains: 2
• Total formula weight: 8253.02

Authors

Berglund, J.A.,Rosbash, M.,Schultz, S.C. (deposition date: 2001-03-21, release date: 2001-09-05, Last modification date: 2024-02-07)

Primary citation

Berglund, J.A.,Rosbash, M.,Schultz, S.C.
Crystal structure of a model branchpoint-U2 snRNA duplex containing bulged adenosines.
RNA, 7:682-691, 2001

PubMed Abstract: Bulged nucleotides play a variety of important roles in RNA structure and function, frequently forming tertiary interactions and sometimes even participating in RNA catalysis. In pre-mRNA splicing, the U2 snRNA base pairs with the intron branchpoint sequence (BPS) to form a short RNA duplex that contains a bulged adenosine that ultimately serves as the nucleophile that attacks the 5' splice site. We have determined a 2.18-A resolution crystal structure of a self-complementary RNA designed to mimic the highly conserved yeast (Saccharomyces cerevisiae) branchpoint sequence (5'-UACUAACGUAGUA with the BPS italicized and the branchsite adenosine underlined) base paired with its complementary sequence from U2 snRNA. The structure shows a nearly ideal A-form helix from which two unpaired adenosines flip out. Although the adenosine adjacent to the branchsite adenosine is the one bulged out in the structure described here, either of these adenosines can serve as the nucleophile in mammalian but not in yeast pre-mRNA splicing. In addition, the packing of the bulged RNA helices within the crystal reveals a novel RNA tertiary interaction in which three RNA helices interact through bulged adenosines in the absence of any divalent metal ions.

PubMed: 11350032
DOI: 10.1017/S1355838201002187

Experimental method

X-RAY DIFFRACTION (2.18 Å)