Journal of Molecular Biology
A change in the twist of the actin-containing filaments occurs during the extension of the acrosomal process in Limulus sperm☆
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Cited by (37)
Structure and dynamic states of actin filaments
2012, Comprehensive BiophysicsStructural dynamics of an actin spring
2011, Biophysical JournalCitation Excerpt :Thus, we see here a third distinct form of actin-based motility similar to a mechanochemical spring with just three components, quite different from polymerization engines (13) based on growth/shrinkage and musclelike motility, where myosin motors move on actin tracks (13). In its coiled state, the bundle is polygonal, with straight sides separated by a set of periodically spaced, sharply bent elbows (kinks) forming a regular 14-gon (Fig. 2 a); along each arm, the actin filaments are supertwisted by ∼60° (14). To understand the kinks, we note that for strong cross-links, i.e., a highly energetic interaction between the scruin-decorated filaments, the best possible way to bend a bundle involves using a series of regularly spaced kinks separated by almost straight sections, rather than having a smoothly bent bundle, as explained qualitatively by DeRosier et al. (10) and calculated theoretically by Cohen and Mahadevan (15).
Force of an actin spring
2007, Biophysical JournalCitation Excerpt :This motility does not involve ATP hydrolysis or a myosin motor protein (10,12). Using electron micrographs of the actin bundle before and after activation, DeRosier and Tilney suggested that the force underlying this motility is a spring-based mechanism in which mechanical energy is stored in slight but concerted overtwists of the actin filaments in the bundle, and our quantitative experiments confirm this hypothesis (13–15). Thus the Limulus sperm acrosome bundle is an example of a third type of actin-based cellular engine—a mechanochemical spring where the relevant displacement governing force generation arises from an overtwist rather than from a rectilinear extension or compression from equilibrium.
Acrosomal actin: Twists and turns of a versatile filament
2004, Current BiologyOrder, disorder, and perturbations in actin-aldolase rafts
2003, Biophysical JournalCitation Excerpt :The layer lines generated from images of rafts are not sufficiently sharp to produce an accurate estimate of the number of units per turn for the actin filaments. We used the frequencies of 13- and 15-subunit cross-bridge spacings, which are set by the helical symmetry of the filaments (DeRosier et al., 1980a; DeRosier and Censullo, 1981; Spudich and Amos, 1979) to determine filament symmetry (see Materials and Methods). The result is approximate because cross-bridge spacings of 11 and 17 subunits are ignored (see Discussion).
Structure and innervation of the cochlea
2003, Brain Research Bulletin
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This work was supported by grants from the National Institutes of Health GM21189 (to D. J. D.) and GB22863 (to L. G. T.).