Search PubMedSearch

PubMed · 2588005

Spatial patterns from oscillating microtubules.

Abstract

Microtubules are fibers of the cytoskeleton involved in the generation of cell shape and motility. They can be highly dynamic and are capable of temporal oscillations in their state of assembly. Solutions of tubulin (the subunit protein of microtubules) and guanosine triphosphate (GTP, the cofactor required for microtubule assembly and oscillations) can generate various dissipative structures. They include traveling waves of microtubule assembly and disassembly as well as polygonal networks. The results imply that cytoskeletal proteins can form dynamic spatial structures by themselves, even in the absence of cellular organizing centers. Thus the microtubule system could serve as a simple model for studying pattern formation by biomolecules in vitro.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

E Mandelkow, E M Mandelkow, H Hotani, B Hess, S C Müller. 1989-12-08. Spatial patterns from oscillating microtubules.. https://doi.org/10.1126/science.2588005

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The mechanism of alpha 1-antitrypsin polymerization probed by fluorescence spectroscopy.

The polymerization of alpha1-antitrypsin within the hepatic cell leads to alpha1-antitrypsin deficiency. Both the conformational changes and the kinetics of the polymerization process are poorly understood. Here we describe fluorescence experiments investigating the polymerization reaction using the fluorescent probe4, 4'-dianilino-1,1'-binaphthyl-5,5'-disulfonate (bis-ANS) which bound to both native and polymerized alpha1-antitrypsin. Biphasic changes in bis-ANS fluorescence were observed during formation of alpha1-antitrypsin polymers. Initially a rapid increase in fluorescence signal was observed; it was followed by a gradual reduction in fluorescence signal. The first phase is a conformational change in which the A beta-sheet of alpha1-antitrypsin opens, whereas the second phase represents the insertion of the reactive center loop into the A beta-sheet of another molecule and therefore determines the rate of the polymerization process.

Biopolymers

Copper-dependent depolymerization of lignin in the presence of fungal metabolite, pyridine.

Thus far, it has not been recognized that copper complexes are able to depolymerize lignin under physiological conditions of white rot decay. However, we have found that both phenolic and non-phenolic synthetic lignins were intensively depolymerized by Cu(II) and lipid hydroperoxide model compounds in the presence of a metabolite of ligninolytic fungi, pyridine at room temperature in aqueous media. Treatment of 14C-labeled oxygen-prebleached kraft pulp (OKP) by the copper-dependent reaction evidenced effectiveness of this reaction for the delignification of kraft pulps. In contrast to the organic peroxide system, Cu(II)/pyr/H2O2 system was much less effective for the lignin depolymerization. However, treatment of unbleached kraft pulp (UKP) by Cu(II)/H2O2 and Cu(II)/pyr/H2O2 systems demonstrated that the damage of cellulose was suppressed by the coordination of pyridine although high brightness gain was obtained independently of the presence of the coordinator. Spin trapping experiments demonstrated that not hydroxyl radical but superoxide anion is involved in the Cu(II)/pyr/H2O2 system. This finding not only introduces a new concept of non-enzymatic lignin biodegradation by wood-degrading fungi but also presents a new strategy for decomposing lignin and lignin-related compounds by copper complexes and peroxide-producing system.

Biopolymers

QCM response to solvated, tethered macromolecules.

When the quartz crystal microbalance (QCM) is operated in contact with solution and used to detect inertia increases caused by macromolecules binding to its surface, resonance frequency shifts are reported in the literature to be greater than, less than, and the same as an identical macromolecular mass would cause as a dry layer. A previous report of wet and dry M13 DNA giving the same, linear frequency versus mass response is examined. The M13 data are shown to follow the reciprocal of the square root of mass, not the reported linear relationship. New experiments on RNA duplexes oscillated in solution are reported. A lossy polymer layer is placed between the QCM and RNA. When changes in density, viscosity, and included water are eliminated, the response remains linear for a constant adlayer thickness. The expectation that response per unit mass should decrease with distance from the QCM surface is demonstrated. Total decoupling of mass lying beyond the acoustic overlayer is also demonstrated. The present results are placed in context with recently published results from a study of progressively thicker protein layers bound to the QCM.

Biopolymers