5fm1 | pdb_00005fm1
Structure of gamma-tubulin small complex based on a cryo-EM map, chemical cross-links, and a remotely related structure
Structural highlights
Function[SPC97_YEAST] Involved in microtubule organization by the microtubule organizing center, the spindle pole body (SPB). Probably part of the microtubule attachment site at the SPB. [TBG_YEAST] Tubulin is the major constituent of microtubules. The gamma chain is found at microtubule organizing centers (MTOC) such as the spindle poles or the centrosome, suggesting that it is involved in the minus-end nucleation of microtubule assembly. TUB4 is an important spindle pole body component that organizes both cytoplasmic and nuclear microtubule arrays. [SPC98_YEAST] Involved in microtubule organization by the microtubule organizing center, the spindle pole body (SPB). Probably part of the microtubule attachment site at the SPB. Publication Abstract from PubMedModeling protein complex structures based on distantly related homologues can be challenging due to poor sequence and structure conservation. Therefore, utilizing even low-resolution experimental data can significantly increase model precision and accuracy. Here, we present models of the two key functional states of the yeast gamma-tubulin small complex (gammaTuSC): one for the low-activity "open" state and another for the higher-activity "closed" state. Both models were computed based on remotely related template structures and cryo-EM density maps at 6.9A and 8.0A resolution, respectively. For each state, extensive sampling of alignments and conformations was guided by the fit to the corresponding cryo-EM density map. The resulting good-scoring models formed a tightly clustered ensemble of conformations in most regions. We found significant structural differences between the two states, primarily in the gamma-tubulin subunit regions where the microtubule binds. We also report a set of chemical cross-links that were found to be consistent with equilibrium between the open and closed states. The protocols developed here have been incorporated into our open-source Integrative Modeling Platform (IMP) software package (https://integrativemodeling.org), and can therefore be applied to many other systems. Structure of gamma-tubulin small complex based on a cryo-EM map, chemical cross-links, and a remotely related structure.,Greenberg CH, Kollman J, Zelter A, Johnson R, MacCoss MJ, Davis TN, Agard DA, Sali A J Struct Biol. 2016 Jun;194(3):303-10. doi: 10.1016/j.jsb.2016.03.006. Epub 2016 , Mar 8. PMID:26968363[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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