1yg4
From Proteopedia
(New page: 200px<br /><applet load="1yg4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1yg4" /> '''Solution Structure of the ScYLV P1-P2 Frames...) |
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'''Solution Structure of the ScYLV P1-P2 Frameshifting Pseudoknot, Regularized Average Structure'''<br /> | '''Solution Structure of the ScYLV P1-P2 Frameshifting Pseudoknot, Regularized Average Structure'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The molecular determinants of stimulation of -1 programmed ribosomal | + | The molecular determinants of stimulation of -1 programmed ribosomal frameshifting (-1 PRF) by RNA pseudoknots are poorly understood. Sugarcane yellow leaf virus (ScYLV) encodes a 28-nt mRNA pseudoknot that promotes -1 PRF between the P1 (protease) and P2 (polymerase) genes in plant luteoviruses. The solution structure of the ScYLV pseudoknot reveals a well ordered loop 2 (L2) that exhibits continuous stacking of A20 through C27 in the minor groove of the upper stem 1 (S1), with C25 flipped out of the triple-stranded stack. Five consecutive triple base pairs flank the helical junction where the 3' nucleotide of L2, C27, adopts a cytidine 27 N3-cytidine 14 2'-OH hydrogen bonding interaction with the C14-G7 base pair. This interaction is isosteric with the adenosine N1-2'-OH interaction in the related mRNA from beet western yellows virus (BWYV); however, the ScYLV and BWYV mRNA structures differ in their detailed L2-S1 hydrogen bonding and L2 stacking interactions. Functional analyses of ScYLV/BWYV chimeric pseudoknots reveal that the ScYLV RNA stimulates a higher level of -1 PRF (15 +/- 2%) relative to the BWYV pseudoknot (6 +/- 1%), a difference traced largely to the identity of the 3' nucleotide of L2 (C27 vs. A25 in BWYV). Strikingly, C27A ScYLV RNA is a poor frameshift stimulator (2.0%) and is destabilized by approximately 1.5 kcal x mol(-1) (pH 7.0, 37 degrees C) with respect to the wild-type pseudoknot. These studies establish that the precise network of weak interactions nearest the helical junction in structurally similar pseudoknots make an important contribution to setting the frameshift efficiency in mRNAs. |
==About this Structure== | ==About this Structure== | ||
| - | 1YG4 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:// | + | 1YG4 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=1YG4 OCA]. |
==Reference== | ==Reference== | ||
A loop 2 cytidine-stem 1 minor groove interaction as a positive determinant for pseudoknot-stimulated -1 ribosomal frameshifting., Cornish PV, Hennig M, Giedroc DP, Proc Natl Acad Sci U S A. 2005 Sep 6;102(36):12694-9. Epub 2005 Aug 25. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16123125 16123125] | A loop 2 cytidine-stem 1 minor groove interaction as a positive determinant for pseudoknot-stimulated -1 ribosomal frameshifting., Cornish PV, Hennig M, Giedroc DP, Proc Natl Acad Sci U S A. 2005 Sep 6;102(36):12694-9. Epub 2005 Aug 25. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16123125 16123125] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Cornish, P | + | [[Category: Cornish, P V.]] |
| - | [[Category: Giedroc, D | + | [[Category: Giedroc, D P.]] |
[[Category: Hennig, M.]] | [[Category: Hennig, M.]] | ||
[[Category: rna pseudoknot; ribosomal frameshifting; protonated cytidine]] | [[Category: rna pseudoknot; ribosomal frameshifting; protonated cytidine]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:05:01 2008'' |
Revision as of 14:05, 21 February 2008
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Solution Structure of the ScYLV P1-P2 Frameshifting Pseudoknot, Regularized Average Structure
Overview
The molecular determinants of stimulation of -1 programmed ribosomal frameshifting (-1 PRF) by RNA pseudoknots are poorly understood. Sugarcane yellow leaf virus (ScYLV) encodes a 28-nt mRNA pseudoknot that promotes -1 PRF between the P1 (protease) and P2 (polymerase) genes in plant luteoviruses. The solution structure of the ScYLV pseudoknot reveals a well ordered loop 2 (L2) that exhibits continuous stacking of A20 through C27 in the minor groove of the upper stem 1 (S1), with C25 flipped out of the triple-stranded stack. Five consecutive triple base pairs flank the helical junction where the 3' nucleotide of L2, C27, adopts a cytidine 27 N3-cytidine 14 2'-OH hydrogen bonding interaction with the C14-G7 base pair. This interaction is isosteric with the adenosine N1-2'-OH interaction in the related mRNA from beet western yellows virus (BWYV); however, the ScYLV and BWYV mRNA structures differ in their detailed L2-S1 hydrogen bonding and L2 stacking interactions. Functional analyses of ScYLV/BWYV chimeric pseudoknots reveal that the ScYLV RNA stimulates a higher level of -1 PRF (15 +/- 2%) relative to the BWYV pseudoknot (6 +/- 1%), a difference traced largely to the identity of the 3' nucleotide of L2 (C27 vs. A25 in BWYV). Strikingly, C27A ScYLV RNA is a poor frameshift stimulator (2.0%) and is destabilized by approximately 1.5 kcal x mol(-1) (pH 7.0, 37 degrees C) with respect to the wild-type pseudoknot. These studies establish that the precise network of weak interactions nearest the helical junction in structurally similar pseudoknots make an important contribution to setting the frameshift efficiency in mRNAs.
About this Structure
1YG4 is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
A loop 2 cytidine-stem 1 minor groove interaction as a positive determinant for pseudoknot-stimulated -1 ribosomal frameshifting., Cornish PV, Hennig M, Giedroc DP, Proc Natl Acad Sci U S A. 2005 Sep 6;102(36):12694-9. Epub 2005 Aug 25. PMID:16123125
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