Relationship
between the flexibility and the motility of actin filaments: effects of pH
Yusuke Arii and Kuniyuki
Hatori*
Department of Bio-System
Engineering,
Graduate School of Science
and Engineering,
Yamagata University
Yonezawa 992-8510, Japan
Abstract
@ Both the sliding velocity
of fluorescently labeled actin filament and its persistence length as an index
of the bending flexibility of the filament were examined in the motility assay
as varying the pH values of the solution for preparing actin filaments. When
the pH value was varied from 5.0 to 9.0 in the solution in which actin
filaments were formed from the constituent monomers, the motile performance of
Mg2+ bound actin filaments (Mg-F-actin) was apparently suppressed
compared to the case of Ca2+ bound ones (Ca-F-actin). The
persistence length for Ca-F-actin gradually increased with the increase of the
pH value while the similar length for Mg-F-actin remained rather independent of
the value. The largest sliding velocity of the filament, on the other hand,
obtained at the persistence length of roughly 6 µm for both cases of
Mg-F-actin and Ca-F-actin.
Keywords: Actin filament; Myosin; Sliding movement; Flexibility;
pH-dependence