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ISSN
1672-9145
Acta Biochim Biophys Sin
2004, 36(9): 637–643 CN 31-1940/Q
Preliminarily Investigating the Polymorphism of Self-organized Actin
Filament in Vitro by Atomic Force Microscope
Jun ZHANG1,2, Yuan-Liang
WANG1*, Xin-Yong Chen3, Chuang-Long HE1,
Chao CHENG1, and Yang CAO1
1Key Lab of Biomechanics & Tissue
Engineering, Chongqing University, Chongqing 400044, China;
2Biology Department, Chongqing University of
Medicine Sciences, Congqing 400016, China;
3Laboratory of Biophysics and Surface Analysis,
University of Nottingham, Nottingham NG7 2RD, United Kingdom
Abstract With the atomic force
microscope (AFM), we preliminarily investigated the large-scale structure of
actin filaments formed in low concentration protein solution (5 mg/ml) via
self-organization without the presence of any F-actin dynamic interfering
factors (such as phalloidin) in vitro. It was found that the G-actin
could be polymerized into ordered filamentous structures with different
diameter from the slimmest filament of single F-actin to giant filament in
tree-like branched aggregates. The observed polymerized actin filaments, to
which our most intense attention was attracted, was discretely distributed and
showed obvious polymorphism distinctly different from those in the presence of
phalloidin or actin binding proteins (fimbrin, gelsolin, etc.) in previous
experiments. Latter structures were mainly composed of single F-actin and/or
multifilaments clearly consisting of several single F-actin. The experimental
results clearly demonstrated that non-interference with the F-actin intrinsic
dynamics in self-organizing could lead to the polymorphism of actin filamentous
structures, and further analysis implied that the disturbance of normal F-actin
dynamics by many factors could prevent the emergence of structural
polymorphism, more often than not, give rise to formation of specific
structures instead and different interference would bring about various
particular structures under certain conditions.
Key words actin; self-organization; filamentous structure; polymorphism;
atomic force microscope
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Received: April 6, 2004 Accepted: August 6, 2004
This work was supported by the grants from the National Natural
Science Foundation of China [No. 19732030 (Key Program), No. 19732003, No.
19872080], and the Visiting Scholar Foundation of Key Lab in Chongqing
University
*Corresponding author: Tel, 86-23-65102508; Fax, 96-23-65316247;
E-mail, [email protected]