Polarity and Motility of Large Polymer−Actin Complexes

Abstract

The polarity of polymer-actin complexes obtained by mixing F-actin with synthetic polymers carrying positive charges such as poly(L-lysine), x,y-ionene bromide polymers, and poly(N-[3-(dimethylamino)propyl]acrylamide) (PDMAPAA-Q) have been investigated. Actin complexes formed with poly(L-lysine) and PDMAPAA-Q, which carry charges on their side chains, show a higher polarity than those formed with x,y-ionene bromide polymers, which have charges on their chain backbones. All these polymer-actin complex gels show motility on the surfaces coated with myosin by coupling to adenosine 5'-triphosphate hydrolysis. A linear correlation between the polarity of polymer-actin complex gels and the motility is observed.

Gel machines constructed from chemically cross-linked actins and myosins

“…Heavy meromyosin (HMM) was obtained by the method of Craig et al [18] . Cationic polymers (x,y-ionene (x=3 or 6; y=3, 4, or 10 ) bromide polymers (x, y-ionene), poly-L-lysine hydrochloride (p-Lys), poly-N- [3-(dimethylamino)propyl]-acrylamide (PDMAPAA-Q)) and other polymer (poly L-glutamic acid sodium salt (p-Glu), Deoxyribonucleic acid sodium salt (DNA), Polyethylene glycol (PEG))were prepared as described in previous papers [13,15] .…”

“…Polarity and motility of polymer-actin complex gel [15] An arrowhead-like pattern can be observed under transmission electron microscopy (TEM) when HMM was decorated on native F-actin (Figure 9a), indicating that F-actin has a well-defined polarity by self-organization. The pointed end of arrowhead and the opposite end of arrowhead are called the p-end and b-end, respectively.…”

“…Recently, we have found that chemically cross-linked giant actin gel filaments, several tens of times the length of native actin filaments, move along a chemically cross-linked myosin fibrous gel with a velocity as high as that of native actins, by coupling to ATP hydrolysis [12][13][14][15] . (Actins and myosins are major component of muscle proteins and play an important role in dynamic motion of creatures that is caused by the molecular deformation using the chemical energy released by hydrolysis of ATP.)…”

Gel biomachine based on muscle proteins

“…The motility of these polymer-actin complex gels will be described in following section. [15] An arrowhead-like pattern can be observed by TEM when HMM was decorated on native F-actin (Figure 5a), indicating that F-actin shows a well-defined polarity by self-organization. The pointed end of arrowhead and the opposite end of arrowhead are called the pointed end (P-end) and barbed end (B-end), respectively.…”

“…This result indicates that muscle proteins can be tailored into desired shape and size without sacrificing their bioactivities. This article reviews recent work on the growth process of polymer-actin complexes in the presence of various polycations and the effect of the polarity of polymer-actin complexes on their velocities [12][13][14][15] . This study has illuminated the creation of ATP fueled biomachine with desired shape and polarity without loss of bioactivity.…”