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Biomedical subjects

E Mandelkow

Publications and source records attributed to E Mandelkow.

At least 127 records · Page 7Linked to original sources
PubMed1980

X-ray kinetic studies of microtubule assembly using synchrotron radiation.

The assembly of microtubules has been investigated by time-resolved X-ray diffraction using synchrotron radiation. The small-angle scattering becomes visible within seconds and thus enables study of the structural transitions of the protein aggregates during assembly from their subunits in solution. The X-ray pattern at 4 degrees C arises from a mixture of tubulin rings, dimers and some other species. Raising the temperature to 36 degrees C induces the breakdown of rings, followed by the growth of microtubules. The results suggest that microtubules may be formed from tubulin oligomers smaller than rings.

Animals↗
PubMed1979

Structural comparisons of the aggregates of tobacco mosaic virus protein.

The coat protein of tobacco mosaic virus forms numerous aggregates, including the small A-protein, the disk, and two helical forms. The structures of the disk, the helical protein forms, and the virus are compared. Most of the differences are in the conformation of the chain between residues 89 and 113, which lies in the region of protein at the center of the virus, inside the RNA. It is disordered in the disk, but has a fixed conformation in the virus and the protein helices. The differences between the virus and the two helical protein forms are largely in the conformations of arginines and carboxylic acids in this region.

Macromolecular Substances↗
PubMed1978

Paracrystalline arrays of membrane-to-membrane cross bridges associated with the inner surface of plasma membrane.

In cultured cells of the rat kangaroo PtK2 line, veils of the cell surface were observed which consisted of only plasma membrane and paracrystalline arrays of membrane-associated particles sandwiched in between. These membrane-to-membrane cross-bridging 9-to 11-nm wide particles were somewhat coumellar-shaped and were arranged on a hexagonal lattice with an interparticle distance of 16nm. At higher magnification, they revealed an unstained core, thus suggesting a ringlike substructure. Similar arrays of paracrystal-containing veils, which were rather variable in size and frequency, were also observed in other cultured cells. It is hypothesized that these paracrystals represent protein macromolecular complexes associated with the inner plasma membrane surface which crystallize when plasma membranes come into close intracellular contact and other components of the subsurface network are removed.

Animals↗
PubMed1977

Tubulin hoops.

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Chemical Phenomena↗
PubMed1977

Microtubule structure at low resolution by x-ray diffraction.

Analysis of x-ray diagrams of oriented hydrated cytoplasmic microtubules shows that the tubule wall extends from about 70 to 150 A radially. The central region of the wall appears homogeneous, but the outside surface is subdivided by vertical grooves separating the 13 protofilaments and by a steep 10-fold family of grooves. The inside surface is dominated by the 10-start grooves with no clear subdivision between the protofilaments.

Animals↗
PubMed1975

Structure of tobacco mosaic virus at 6.7 å resolution.

The electron density distribution of tobacco mosaic virus has been determined to 6.7 A resolution by analysis of the X-ray diffraction pattern given by oriented gels of the virus. This has been achieved by separation of overlapping Bessel function terms by a technique analogous to crystallographic isomorphous replacement. The course of the polypeptide chain of the coat protein may be traced for a large part of its length.

Fourier Analysis↗
PubMedDate not supplied

Paracrystalline structure of the stalk domain of the microtubule motor protein kinesin.

We have studied single molecules and paracrystals of the stalk domain of the microtubule motor protein, kinesin, using circular dichroism, electron microscopy, and optical diffraction. The stalk is a rod-like particle, about 50 nm in length, with about 70% alpha-helical content (lower than tropomyosin and myosin). These data confirm the previous studies of M. De Cuevas, T. Tao, and L.S. B. Goldstein (J. Cell Biol. 116, 957-966, 1992). The particles also show a tendency to self-associate into dimers or higher aggregates, up to paracrystals with a periodic substructure. Four types of paracrystals have been observed, two with short periodicities (8 and 13 nm, types I and II) and two with periodicities comparable with the subunit length (53-63 nm, type III and 38 nm, type IV). Types I and II paracrystals can be interpreted to arise from a polar arrangement of subunits with alternating gaps and overlaps and different staggers between adjacent molecules. Type III and IV paracrystals appear to be formed from sets of antiparallel molecules, forming centrosymmetric patterns. The association properties may be important for functions of the kinesin stalk in microtubule-dependent motility.

Animals↗