Abstract:
:Chromosome movement during mitosis is powered in part by energy released through the depolymerization of kinetochore microtubules (MTs). Strong but indirect evidence suggests the existence of a specialized coupling between kinetochores and MT plus ends that enables this transduction of chemical energy into mechanical work. Analysis of this phenomenon is important for learning how energy is stored within the MT lattice, how it is transduced, and how efficient the process can be, given coupling devices of different designs. Here we use a recently developed molecular-mechanical model of MTs to examine the mechanism of disassembly dependent force generation. Our approach is based on changes in tubulin dimer conformation that occur during MT disassembly. We find that all of the energy of polymerization-associated GTP hydrolysis can be stored as deformations of the longitudinal bonds between tubulin dimers, and its optimal use does not require the weakening of lateral bonds between dimers. Maximum utilization of this stored energy and, hence, the generation of the strongest possible force, is achieved by a protofilament power-stroke mechanism, so long as the coupling device does not restrict full dissociation of the lateral bonds between tubulin dimers.
journal_name
Proc Natl Acad Sci U S Aauthors
Molodtsov MI,Grishchuk EL,Efremov AK,McIntosh JR,Ataullakhanov FIdoi
10.1073/pnas.0501142102keywords:
subject
Has Abstractpub_date
2005-03-22 00:00:00pages
4353-8issue
12eissn
0027-8424issn
1091-6490pii
0501142102journal_volume
102pub_type
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