1yfq

<StructureSection load='1yfq' size='340' side='right' caption='[[1yfq]], [[Resolution|resolution]] 1.10&Aring;' scene=''>

<table><tr><td colspan='2'>[[1yfq]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Atcc_18824 Atcc 18824]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1YFQ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1YFQ FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">BUB3 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=4932 ATCC 18824])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1yfq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1yfq OCA], [http://pdbe.org/1yfq PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1yfq RCSB], [http://www.ebi.ac.uk/pdbsum/1yfq PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1yfq ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/BUB3_YEAST BUB3_YEAST]] Required for cell cycle arrest in response to loss of microtubule function. Component of the spindle assembly checkpoint which is a feedback control that prevents cells with incompletely assembled spindles from leaving mitosis. Component of the mitotic checkpoint complex (MCC) which inhibits the ubiquitin ligase activity of the anaphase promoting complex/cyclosome (APC/C) by preventing its activation by CDC20. The formation of a MAD1-BUB1-BUB3 complex seems to be required for the spindle checkpoint mechanism.<ref>PMID:15879521</ref>

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== Publication Abstract from PubMed ==

Bub3p is a protein that mediates the spindle checkpoint, a signaling pathway that ensures correct chromosome segregation in organisms ranging from yeast to mammals. It is known to function by co-localizing at least two other proteins, Mad3p and the protein kinase Bub1p, to the kinetochore of chromosomes that are not properly attached to mitotic spindles, ultimately resulting in cell cycle arrest. Prior sequence analysis suggested that Bub3p was composed of three or four WD repeats (also known as WD40 and beta-transducin repeats), short sequence motifs appearing in clusters of 4-16 found in many hundreds of eukaryotic proteins that fold into four-stranded blade-like sheets. We have determined the crystal structure of Bub3p from Saccharomyces cerevisiae at 1.1 angstrom and a crystallographic R-factor of 15.3%, revealing seven authentic repeats. In light of this, it appears that many of these repeats therefore remain hidden in sequences of other proteins. Analysis of random and site-directed mutants identifies the surface of Bub3p involved in checkpoint function through binding of Bub1p and Mad3p. Sequence alignments indicate that these surfaces are mostly conserved across Bub3 proteins from diverse species. A structural comparison with other proteins containing WD repeats suggests that these folds may bind partner proteins using similar surface areas on the top and sides of the propeller. The sequences composing these regions are the most divergent within the repeat across all WD repeat proteins and could potentially be modulated to provide specificity in partner protein binding without perturbation of the core structure.

The 1.1-angstrom structure of the spindle checkpoint protein Bub3p reveals functional regions.,Wilson DK, Cerna D, Chew E J Biol Chem. 2005 Apr 8;280(14):13944-51. Epub 2005 Jan 11. PMID:15644329<ref>PMID:15644329</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1yfq" style="background-color:#fffaf0;"></div>

[[Category: Atcc 18824]]

[[Category: Cerna, D]]

[[Category: Chew, E]]

[[Category: Wilson, D K]]

[[Category: Signaling protein]]

[[Category: Wd repeat wd40 repeat beta transducin repeat all beta]]