1u4c

Structure of spindle checkpoint protein Bub3

spinqualitylabelsall models 1u4c, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1u4c is a 2 chain structure with sequence from Atcc 18824. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: MSE Gene: BUB3 (ATCC 18824) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [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. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Bub3 is one of at least six proteins that transmit the spindle assembly checkpoint signal. These proteins delay cell cycle progression from metaphase to anaphase in response to attachment defects between kinetochores and spindle microtubules and to tension defects between sister chromatids. To explore the molecular interactions mediated by Bub3, we have determined the crystal structure of the Saccharomyces cerevisiae protein Bub3p at 2.35 A resolution. Bub3p is a seven-blade beta-propeller, although its sequence diverges from that of other WD40 family members. Several loops are substantially elongated, but extra domains or insertions are not present at the termini. In particular, two extended loops project from the top face of the propeller, forming a cleft. Amino acid residues across the top face and one aspect of the lateral surface (spanning blades 5-6) are highly conserved among Bub3 proteins. We propose that these conserved surfaces are the loci for key interactions with conserved motifs in spindle checkpoint proteins Bub1 and Mad3/BubR1. Comparison of the Bub3 sequence to the WD40 protein, Rae1, shows high sequence conservation along the same surfaces. Rae1 interaction with Bub1 is, therefore, likely to involve a similar mode of binding. Crystal structure of the spindle assembly checkpoint protein Bub3.,Larsen NA, Harrison SC J Mol Biol. 2004 Dec 3;344(4):885-92. PMID:15544799 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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