1i3y
From Proteopedia
(New page: 200px<br /><applet load="1i3y" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i3y" /> '''SOLUTION STRUCTURE OF THE A LOOP OF 23S RIBO...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1i3y.gif|left|200px]]<br /><applet load="1i3y" size=" | + | [[Image:1i3y.gif|left|200px]]<br /><applet load="1i3y" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1i3y" /> | caption="1i3y" /> | ||
'''SOLUTION STRUCTURE OF THE A LOOP OF 23S RIBOSOMAL RNA.'''<br /> | '''SOLUTION STRUCTURE OF THE A LOOP OF 23S RIBOSOMAL RNA.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The A loop is an essential RNA component of the ribosome | + | The A loop is an essential RNA component of the ribosome peptidyltransferase center that directly interacts with aminoacyl (A)-site tRNA. The A loop is highly conserved and contains a ubiquitous 2'-O-methyl ribose modification at position U2552. Here, we present the solution structure of a modified and unmodified A-loop RNA to define both the A-loop fold and the structural impact of the U2552 modification. Solution data reveal that the A-loop RNA has a compact structure that includes a noncanonical base pair between C2556 and U2552. NMR evidence is presented that the N3 position of C2556 has a shifted pKa and that protonation at C2556-N3 changes the C-U pair geometry. Our data indicate that U2552 methylation modifies the A-loop fold, in particular the dynamics and position of residues C2556 and U2555. We compare our structural data with the structure of the A loop observed in a recent 50S crystal structure [Ban, N., Nissen, P., Hansen, J., Moore, P. B. & Steitz, T. A. (2000) Science 289, 905--920; Nissen, P., Hansen, J., Ban, N., Moore, P. B. & Steitz, T. A. (2000) Science 289, 920--930]. The solution and crystal structures of the A loop are dramatically different, suggesting that a structural rearrangement of the A loop must occur on docking into the peptidyltransferase center. Possible roles of this docking event, the shifted pKa of C2556 and the U2552 2'-O-methylation in the mechanism of translation, are discussed. |
==About this Structure== | ==About this Structure== | ||
| - | 1I3Y 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:// | + | 1I3Y 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://oca.weizmann.ac.il/oca-bin/ocashort?id=1I3Y OCA]. |
==Reference== | ==Reference== | ||
Solution structure of the A loop of 23S ribosomal RNA., Blanchard SC, Puglisi JD, Proc Natl Acad Sci U S A. 2001 Mar 27;98(7):3720-5. Epub 2001 Mar 20. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11259644 11259644] | Solution structure of the A loop of 23S ribosomal RNA., Blanchard SC, Puglisi JD, Proc Natl Acad Sci U S A. 2001 Mar 27;98(7):3720-5. Epub 2001 Mar 20. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11259644 11259644] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Blanchard, S | + | [[Category: Blanchard, S C.]] |
| - | [[Category: Puglisi, J | + | [[Category: Puglisi, J D.]] |
[[Category: 23s rrna]] | [[Category: 23s rrna]] | ||
[[Category: a loop]] | [[Category: a loop]] | ||
[[Category: a site]] | [[Category: a site]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:07:42 2008'' |
Revision as of 11:07, 21 February 2008
|
SOLUTION STRUCTURE OF THE A LOOP OF 23S RIBOSOMAL RNA.
Overview
The A loop is an essential RNA component of the ribosome peptidyltransferase center that directly interacts with aminoacyl (A)-site tRNA. The A loop is highly conserved and contains a ubiquitous 2'-O-methyl ribose modification at position U2552. Here, we present the solution structure of a modified and unmodified A-loop RNA to define both the A-loop fold and the structural impact of the U2552 modification. Solution data reveal that the A-loop RNA has a compact structure that includes a noncanonical base pair between C2556 and U2552. NMR evidence is presented that the N3 position of C2556 has a shifted pKa and that protonation at C2556-N3 changes the C-U pair geometry. Our data indicate that U2552 methylation modifies the A-loop fold, in particular the dynamics and position of residues C2556 and U2555. We compare our structural data with the structure of the A loop observed in a recent 50S crystal structure [Ban, N., Nissen, P., Hansen, J., Moore, P. B. & Steitz, T. A. (2000) Science 289, 905--920; Nissen, P., Hansen, J., Ban, N., Moore, P. B. & Steitz, T. A. (2000) Science 289, 920--930]. The solution and crystal structures of the A loop are dramatically different, suggesting that a structural rearrangement of the A loop must occur on docking into the peptidyltransferase center. Possible roles of this docking event, the shifted pKa of C2556 and the U2552 2'-O-methylation in the mechanism of translation, are discussed.
About this Structure
1I3Y is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Solution structure of the A loop of 23S ribosomal RNA., Blanchard SC, Puglisi JD, Proc Natl Acad Sci U S A. 2001 Mar 27;98(7):3720-5. Epub 2001 Mar 20. PMID:11259644
Page seeded by OCA on Thu Feb 21 13:07:42 2008
