1sq9: Difference between revisions

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New page: left|200px<br /><applet load="1sq9" size="450" color="white" frame="true" align="right" spinBox="true" caption="1sq9, resolution 1.9Å" /> '''Structure of Ski8p, a...
 
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[[Image:1sq9.jpg|left|200px]]<br /><applet load="1sq9" size="450" color="white" frame="true" align="right" spinBox="true"  
[[Image:1sq9.jpg|left|200px]]<br /><applet load="1sq9" size="350" color="white" frame="true" align="right" spinBox="true"  
caption="1sq9, resolution 1.9&Aring;" />
caption="1sq9, resolution 1.9&Aring;" />
'''Structure of Ski8p, a WD repeat protein involved in mRNA degradation and meiotic recombination'''<br />
'''Structure of Ski8p, a WD repeat protein involved in mRNA degradation and meiotic recombination'''<br />


==Overview==
==Overview==
Ski8p is a 44-kD protein that primarily functions in the regulation of, exosome-mediated, 3'--&gt; 5' degradation of damaged mRNA. It does so by, forming a complex with two partner proteins, Ski2p and Ski3p, which, complete a complex that is capable of recruiting and activating the, exosome/Ski7p complex that functions in RNA degradation. Ski8p also, functions in meiotic recombination in complex with Spo11 in yeast. It is, one of the many hundreds of primarily eukaryotic proteins containing, tandem copies of WD repeats (also known as WD40 or beta-transducin, repeats), which are short ~40 amino acid motifs, often terminating in a, Trp-Asp dipeptide. Genomic analyses have demonstrated that WD repeats are, found in 1%-2% of proteins in a typical eukaryote, but are extremely rare, in prokaryotes. Almost all structurally characterized WD-repeat proteins, are composed of seven such repeats and fold into seven-bladed beta, propellers. Ski8p was thought to contain five WD repeats on the basis of, primary sequence analysis implying a five-bladed propeller. The 1.9 A, crystal structure unexpectedly exhibits a seven-bladed propeller fold with, seven structurally authentic WD repeats. Structure-based sequence, alignments show additional sequence diversity in the two undetected, repeats. This demonstrates that many WD repeats have not yet been, identified in sequences and also raises the possibility that the, seven-bladed propeller may be the predominant fold for this family of, proteins.
Ski8p is a 44-kD protein that primarily functions in the regulation of exosome-mediated, 3'--&gt; 5' degradation of damaged mRNA. It does so by forming a complex with two partner proteins, Ski2p and Ski3p, which complete a complex that is capable of recruiting and activating the exosome/Ski7p complex that functions in RNA degradation. Ski8p also functions in meiotic recombination in complex with Spo11 in yeast. It is one of the many hundreds of primarily eukaryotic proteins containing tandem copies of WD repeats (also known as WD40 or beta-transducin repeats), which are short ~40 amino acid motifs, often terminating in a Trp-Asp dipeptide. Genomic analyses have demonstrated that WD repeats are found in 1%-2% of proteins in a typical eukaryote, but are extremely rare in prokaryotes. Almost all structurally characterized WD-repeat proteins are composed of seven such repeats and fold into seven-bladed beta propellers. Ski8p was thought to contain five WD repeats on the basis of primary sequence analysis implying a five-bladed propeller. The 1.9 A crystal structure unexpectedly exhibits a seven-bladed propeller fold with seven structurally authentic WD repeats. Structure-based sequence alignments show additional sequence diversity in the two undetected repeats. This demonstrates that many WD repeats have not yet been identified in sequences and also raises the possibility that the seven-bladed propeller may be the predominant fold for this family of proteins.


==About this Structure==
==About this Structure==
1SQ9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1SQ9 OCA].  
1SQ9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SQ9 OCA].  


==Reference==
==Reference==
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[[Category: Saccharomyces cerevisiae]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Single protein]]
[[Category: Single protein]]
[[Category: Madrona, A.Y.]]
[[Category: Madrona, A Y.]]
[[Category: Wilson, D.K.]]
[[Category: Wilson, D K.]]
[[Category: SO4]]
[[Category: SO4]]
[[Category: beta propeller]]
[[Category: beta propeller]]
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[[Category: wd40 repeat]]
[[Category: wd40 repeat]]


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