Prp24: Difference between revisions
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Prp24 contains four RRMs, RRM 1, RRM 2, RRM 3, and RRM 4. These motifs have a <scene name='Sandbox_Reserved_340/2ghp/19'>canonical structure of a platform of four β-strands with two α-helices on one side of the β-sheet plane</scene>. These RRMs are present in many proteins that bind to to single stranded regions of RNA <ref name="RRM"/> and their presence in Prp24 supports a role for the annealing of U4 and U6 snRNAs into the U4/U6 structure. | Prp24 contains four RRMs, RRM 1, RRM 2, RRM 3, and RRM 4. These motifs have a <scene name='Sandbox_Reserved_340/2ghp/19'>canonical structure of a platform of four β-strands with two α-helices on one side of the β-sheet plane</scene>. These RRMs are present in many proteins that bind to to single stranded regions of RNA <ref name="RRM"/> and their presence in Prp24 supports a role for the annealing of U4 and U6 snRNAs into the U4/U6 structure. | ||
Within each RRM, there are RNP consensus domains <ref name="RRM">PMID:15853797</ref>. These are the regions in the β-strands that are thought to actually interact with the RNA <ref name="RRM"/>. These regions seem to be very important in Prp24 and its interaction with U4 and U6. The study that first identified a probable link between the Prp24 protein and U4/U6 found <scene name='Sandbox_Reserved_340/2ghp/ | Within each RRM, there are RNP consensus domains <ref name="RRM">PMID:15853797</ref>. These are the regions in the β-strands that are thought to actually interact with the RNA <ref name="RRM"/>. These regions seem to be very important in Prp24 and its interaction with U4 and U6. The study that first identified a probable link between the Prp24 protein and U4/U6 found <scene name='Sandbox_Reserved_340/2ghp/24'>mutations in RNP 1 and RNP 2 of the RRM 3</scene> that rescued a cold-sensitive phenotype caused by a U4 mutation in stem II of U4/U6 <ref name="Shannon"/>. Two further studies <ref name="Vidaver"/> <ref name="Kwan">PMID:15811912</ref> showed that the mutation of <scene name='Sandbox_Reserved_340/2ghp/26'>three highly conserved residues in the RNP domains</scene> of any of the four RRMs conferred either temperature-sensitive growth or lethality to yeast cells. | ||
===Structural Models=== | ===Structural Models=== | ||
A recent study <ref name="Bae"/> examined the structure of <scene name='Sandbox_Reserved_340/2ghp/ | A recent study <ref name="Bae"/> examined the structure of <scene name='Sandbox_Reserved_340/2ghp/25'>the first three RRMs</scene>of Prp24 by X-ray crystallography. The resultant structure showed Prp24 as an <scene name='Sandbox_Reserved_340/2ghp/23'>octameric protein</scene>, consisting of eight chains arranged in two nearly symmetrical tetramers<ref name="Bae"/>. This was the first suggested that Prp24 functioned as an multimer, so it is unclear what the significance of this result is <ref name="Bae"/>. Their crystal structure also showed extensive interactions between both <scene name='Sandbox_Reserved_340/2ghp/21'>RRM 1 and 2</scene> and <scene name='Sandbox_Reserved_340/2ghp/22'>RRM 2 and 3</scene>, and NMR analysis of protein fragments containing either RRMs 1 and 2 or RRMs 2 and 3 showed that these interactions existed in solution as well<ref name="Bae"/>. Interestingly, these interactions seemed to block the proposed U6 binding sites of RRM 1 and 2; NMR analysis of the RRM 1 and 2 protein fragment with an RNA oligomer containing the U6 sequences thought to bind the RRMs showed a largely canonical interaction of the RNA with the RRMs, suggesting that Prp24 may undergo conformational changes in the binding of U6<ref name="Bae"/>. | ||
== Functional Interactions == | == Functional Interactions == | ||