Mechanism and dynamics of breakage of Fluorescent
Microtubules
Honglian Guo 1*, Chunhua Xu 1, Chunxiang Liu 2, E Qu 1, Ming Yuan 3, Zhaolin Li 1, Bingying cheng 1 and Daozhong Zhang 1
1 Institute of Physics, Chinese Academy of Sciences
2 Department of Physics, Shandong Normal University
3 College of Biological Sciences, China Agricultural University
* To whom correspondence should be addressed. E-mail: hlguo{at}aphy.iphy.ac.cn.
Submitted on July 21, 2005
Revised on August 22, 2005
Accepted on 15 November 2005
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Abstract |
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The breakage of fluorescence labeled microtubules under irradiation of excitation light is found in our experiments. Its mechanism is studied. The results indicate that free radicals are the main reason for the photosensitive breakage. Furthermore, the mechanical properties of the microtubules are probed with dual-optical tweezers system. It is found that the fluorescence labeled microtubules are much easier to be extended compared with those without fluorescence. Such microtubule can be extended by 30% and the force for breaking up is only several piconewtons. In addition, we find that the breakup of the protofilaments is not simultaneous but step-by-step, which further confirm that the interaction between protofilaments is fairly weak.
Key Words:
breakage, fluorescence, free radicals, mechanical properties, microtubule, optical tweezers
