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5flz

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Revision as of 16:47, 10 May 2016

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Cryo-EM structure of gamma-TuSC oligomers in a closed conformation

Structural highlights

5flz is a 6 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
NonStd Res:
Related:	5fm1
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum

Warning: this is a large structure, and loading might take a long time or not happen at all.

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 PubMed

Modeling 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 (http://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

↑ Greenberg CH, Kollman J, Zelter A, Johnson R, MacCoss MJ, Davis TN, Agard DA, Sali A. Structure of gamma-tubulin small complex based on a cryo-EM map, chemical cross-links, and a remotely related structure. J Struct Biol. 2016 Jun;194(3):303-10. doi: 10.1016/j.jsb.2016.03.006. Epub 2016 , Mar 8. PMID:26968363 doi:http://dx.doi.org/10.1016/j.jsb.2016.03.006

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/5flz"

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+{{Large structure}}
 ==Cryo-EM structure of gamma-TuSC oligomers in a closed conformation==
 <StructureSection load='5flz' size='340' side='right' caption='[[5flz]], [[Resolution|resolution]] 6.90&Aring;' scene=''>
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 <div style="background-color:#fffaf0;">
 == Publication Abstract from PubMed ==
-The gamma-tubulin ring complex (gammaTuRC) is the primary microtubule nucleator in cells. gammaTuRC is assembled from repeating gamma-tubulin small complex (gammaTuSC) subunits and is thought to function as a template by presenting a gamma-tubulin ring that mimics microtubule geometry. However, a previous yeast gammaTuRC structure showed gammaTuSC in an open conformation that prevents matching to microtubule symmetry. By contrast, we show here that gamma-tubulin complexes are in a closed conformation when attached to microtubules. To confirm the functional importance of the closed gammaTuSC ring, we trapped the closed state and determined its structure, showing that the gamma-tubulin ring precisely matches microtubule symmetry and providing detailed insight into gammaTuRC architecture. Importantly, the closed state is a stronger nucleator, thus suggesting that this conformational switch may allosterically control gammaTuRC activity. Finally, we demonstrate that gammaTuRCs have a strong preference for tubulin from the same species.
+Modeling 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 (http://integrativemodeling.org), and can therefore be applied to many other systems.
-Ring closure activates yeast gammaTuRC for species-specific microtubule nucleation.,Kollman JM, Greenberg CH, Li S, Moritz M, Zelter A, Fong KK, Fernandez JJ, Sali A, Kilmartin J, Davis TN, Agard DA Nat Struct Mol Biol. 2015 Feb;22(2):132-7. doi: 10.1038/nsmb.2953. Epub 2015 Jan , 19. PMID:25599398<ref>PMID:25599398</ref>
+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<ref>PMID:26968363</ref>
 From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

5flz

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Revision as of 16:47, 10 May 2016

Cryo-EM structure of gamma-TuSC oligomers in a closed conformation

Structural highlights

Function

Publication Abstract from PubMed

References

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Proteopedia Page Contributors and Editors (what is this?)

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