3cb2: Difference between revisions
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New page: '''Unreleased structure''' The entry 3cb2 is ON HOLD until Paper Publication Authors: Rice, L.M., Montabana, E.A., Agard, D.A. Description: Crystal structure of human gamma-tubulin bou... |
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{{STRUCTURE_3cb2| PDB=3cb2 | SCENE= }} | |||
'''Crystal structure of human gamma-tubulin bound to GDP''' | |||
==Overview== | |||
GTP-dependent microtubule polymerization dynamics are required for cell division and are accompanied by domain rearrangements in the polymerizing subunit, alphabeta-tubulin. Two opposing models describe the role of GTP and its relationship to conformational change in alphabeta-tubulin. The allosteric model posits that unpolymerized alphabeta-tubulin adopts a more polymerization-competent conformation upon GTP binding. The lattice model posits that conformational changes occur only upon recruitment into the growing lattice. Published data support a lattice model, but are largely indirect and so the allosteric model has prevailed. We present two independent solution probes of the conformation of alphabeta-tubulin, the 2.3 A crystal structure of gamma-tubulin bound to GDP, and kinetic simulations to interpret the functional consequences of the structural data. These results (with our previous gamma-tubulin:GTPgammaS structure) support the lattice model by demonstrating that major domain rearrangements do not occur in eukaryotic tubulins in response to GTP binding, and that the unpolymerized conformation of alphabeta-tubulin differs significantly from the polymerized one. Thus, geometric constraints of lateral self-assembly must drive alphabeta-tubulin conformational changes, whereas GTP plays a secondary role to tune the strength of longitudinal contacts within the microtubule lattice. alphabeta-Tubulin behaves like a bent spring, resisting straightening until forced to do so by GTP-mediated interactions with the growing microtubule. Kinetic simulations demonstrate that resistance to straightening opposes microtubule initiation by specifically destabilizing early assembly intermediates that are especially sensitive to the strength of lateral interactions. These data provide new insights into the molecular origins of dynamic microtubule behavior. | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 11 | ==About this Structure== | ||
3CB2 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3CB2 OCA]. | |||
==Reference== | |||
The lattice as allosteric effector: structural studies of alphabeta- and gamma-tubulin clarify the role of GTP in microtubule assembly., Rice LM, Montabana EA, Agard DA, Proc Natl Acad Sci U S A. 2008 Apr 8;105(14):5378-83. Epub 2008 Apr 3. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18388201 18388201] | |||
[[Category: Homo sapiens]] | |||
[[Category: Single protein]] | |||
[[Category: Tubulin GTPase]] | |||
[[Category: Agard, D A.]] | |||
[[Category: Montabana, E A.]] | |||
[[Category: Rice, L M.]] | |||
[[Category: Gtpase]] | |||
[[Category: Hydrolase]] | |||
[[Category: Lateral interaction]] | |||
[[Category: Lattice]] | |||
[[Category: Microtubule]] | |||
[[Category: Nucleation]] | |||
[[Category: Structural protein]] | |||
[[Category: Tubulin]] | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 11 10:48:41 2008'' | |||