1i9x

[[Image:1i9x.gif|left|200px]]<br /><applet load="1i9x" size="450" color="white" frame="true" align="right" spinBox="true"

caption="1i9x, resolution 2.18&Aring;" />

'''CRYSTAL STRUCTURE OF BPS-U2 SNRNA DUPLEX'''<br />

==Overview==

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.

 

==About this Structure==

1I9X is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1I9X OCA].

 

==Reference==

Crystal structure of a model branchpoint-U2 snRNA duplex containing bulged adenosines., Berglund JA, Rosbash M, Schultz SC, RNA. 2001 May;7(5):682-91. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11350032 11350032]

[[Category: Protein complex]]

[[Category: Berglund, J.A.]]

[[Category: Rosbash, M.]]

[[Category: Schultz, S.C.]]

[[Category: bulged adenosine]]

[[Category: pre-mrna splicing]]

[[Category: three helix junction]]

 

''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Sun Nov 25 03:50:41 2007''