title: Mechanism and dynamics of breakage of fluorescent microtubules.
abstract: 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 a dual-optical tweezers system. It is found that the fluorescence-labeled microtubules are much easier to extend compared with those without fluorescence. Such microtubules can be extended by 30%, and the force for breaking them up is only several piconewtons. In addition, we find that the breakup of the protofilaments is not simultaneous but step-by-step, which further confirms that the interaction between protofilaments is fairly weak.
authors.affiliation: Optical Physics Laboratory, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China. hlguo@aphy.iphy.ac.cn
authors.forename: Honglian
authors.initials: H
authors.lastname: Guo
authors.forename: Chunhua
authors.initials: C
authors.lastname: Xu
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Liu
authors.forename: E
authors.initials: E
authors.lastname: Qu
authors.forename: Ming
authors.initials: M
authors.lastname: Yuan
authors.forename: Zhaolin
authors.initials: Z
authors.lastname: Li
authors.forename: Bingying
authors.initials: B
authors.lastname: Cheng
authors.forename: Daozhong
authors.initials: D
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D004307:Dose-Response Relationship, Radiation; D004548:Elasticity / Q000528:radiation effects; D008027:Light; D008846:Micromanipulation / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods*; D008870:Microtubules / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure*; D011487:Protein Conformation / Q000528:radiation effects; D011829:Radiation Dosage; D013314:Stress, Mechanical; D013552:Swine; D014404:Tubulin / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure*
chemical_list: D014404:Tubulin