5fm1

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(Difference between revisions)

Revision as of 17:02, 10 May 2016

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Structure of gamma-tubulin small complex based on a cryo-EM map, chemical cross-links, and a remotely related structure

Structural highlights

5fm1 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:	5flz
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/5fm1"

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+{{Large structure}}
 ==Structure of gamma-tubulin small complex based on a cryo-EM map, chemical cross-links, and a remotely related structure==
 <StructureSection load='5fm1' size='340' side='right' caption='[[5fm1]], [[Resolution|resolution]] 8.00&Aring;' scene=''>
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 <div style="background-color:#fffaf0;">
 == Publication Abstract from PubMed ==
-Microtubules are nucleated in vivo by gamma-tubulin complexes. The 300-kDa gamma-tubulin small complex (gamma-TuSC), consisting of two molecules of gamma-tubulin and one copy each of the accessory proteins Spc97 and Spc98, is the conserved, essential core of the microtubule nucleating machinery. In metazoa multiple gamma-TuSCs assemble with other proteins into gamma-tubulin ring complexes (gamma-TuRCs). The structure of gamma-TuRC indicated that it functions as a microtubule template. Because each gamma-TuSC contains two molecules of gamma-tubulin, it was assumed that the gamma-TuRC-specific proteins are required to organize gamma-TuSCs to match 13-fold microtubule symmetry. Here we show that Saccharomyces cerevisiae gamma-TuSC forms rings even in the absence of other gamma-TuRC components. The yeast adaptor protein Spc110 stabilizes the rings into extended filaments and is required for oligomer formation under physiological buffer conditions. The 8-A cryo-electron microscopic reconstruction of the filament reveals 13 gamma-tubulins per turn, matching microtubule symmetry, with plus ends exposed for interaction with microtubules, implying that one turn of the filament constitutes a microtubule template. The domain structures of Spc97 and Spc98 suggest functions for conserved sequence motifs, with implications for the gamma-TuRC-specific proteins. The gamma-TuSC filaments nucleate microtubules at a low level, and the structure provides a strong hypothesis for how nucleation is regulated, converting this less active form to a potent nucleator.
+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.
-Microtubule nucleating gamma-TuSC assembles structures with 13-fold microtubule-like symmetry.,Kollman JM, Polka JK, Zelter A, Davis TN, Agard DA Nature. 2010 Aug 12;466(7308):879-82. doi: 10.1038/nature09207. Epub 2010 Jul 14. PMID:20631709<ref>PMID:20631709</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>

5fm1

From Proteopedia

Revision as of 17:02, 10 May 2016

Structure of gamma-tubulin small complex based on a cryo-EM map, chemical cross-links, and a remotely related structure

Structural highlights

Function

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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