Structure of Gamma-Tubulin Small Complex Based on a Cryo-Em Map, Chemical Cross-Links, and a Remotely Related Structure.Greenberg, C.H., Kollman, J., Zelter, A., Johnson, R., Maccoss, M.J., Davis, T.N., Agard, D.A., Sali, A.
(2016) J Struct Biol 194: 303
- PubMed: 26968363
- DOI: 10.1016/j.jsb.2016.03.006
- Primary Citation of Related Structures:
- PubMed Abstract:
- Ring Closure Activates Yeast Gamma-Turc for Species-Specific Microtubule Nucleation.
Kollman, J.M., Greenberg, C.H., Li, S., Moritz, M., Zelter, A., Fong, K.K., Fernandez, J., Sali, A., Kilmartin, J., Davis, T.N., Agard, D.A.
(2015) Nat Struct Mol Biol 22: 132
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 ...
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 γ-tubulin small complex (γTuSC): 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 6.9Å and 8.0Å 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 γ-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.
Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California at San Francisco, San Francisco, CA, USA. Electronic address: firstname.lastname@example.org.