Ronald J. Baskin

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Chromosome segregation during mitosis depends on the action of the mitotic spindle, a self-organizing, bipolar protein machine which uses microtubules (MTs) and their associated motors. Members of the BimC subfamily of kinesin-related MT-motor proteins are believed to be essential for the formation and functioning of a normal bipolar spindle. Here we report(More)
RecBCD enzyme is a processive DNA helicase and nuclease that participates in the repair of chromosomal DNA through homologous recombination. We have visualized directly the movement of individual RecBCD enzymes on single molecules of double-stranded DNA (dsDNA). Detection involves the optical trapping of solitary, fluorescently tagged dsDNA molecules that(More)
To understand the roles of kinesin and its relatives in cell division, it is necessary to identify and characterize multiple members of the kinesin superfamily from mitotic cells. To this end we have raised antisera to peptides corresponding to highly conserved regions of the motor domains of several known members of the kinesin superfamily. These peptide(More)
Escherichia coli RecA is essential for the repair of DNA double-strand breaks by homologous recombination. Repair requires the formation of a RecA nucleoprotein filament. Previous studies have indicated a mechanism of filament assembly whereby slow nucleation of RecA protein on DNA is followed by rapid growth. However, many aspects of this process remain(More)
RecBCD enzyme is a heterotrimeric helicase/nuclease that initiates homologous recombination at double-stranded DNA breaks. Several of its activities are regulated by the DNA sequence chi (5'-GCTGGTGG-3'), which is recognized in cis by the translocating enzyme. When RecBCD enzyme encounters chi, the intensity and polarity of its nuclease activity are(More)
Fragmented sarcoplasmic reticulum (FSR) from rabbit muscle was examined by positive staining, negative staining, and freeze-etch electron microscopic techniques in the absence and presence of calcium transport conditions. The existence of 30-40 A particles covering the outer surface of FSR vesicles was confirmed by two different negative stains in unfixed,(More)
NOD is a Drosophila chromosome-associated kinesin-like protein that does not fall into the chromokinesin subfamily. Although NOD lacks residues known to be critical for kinesin function, we show that microtubules activate the ATPase activity of NOD >2000-fold. Biochemical and genetic analysis of two genetically identified mutations of NOD (NOD(DTW) and(More)
Light diffraction patterns from isolated frog semitendinosus muscle fibers were examined. When transilluminated by laser light, the muscle striations produce a diffraction pattern consisting of a series of lines that are projected as points onto an optical detector by a lens system. Diffraction data may be sequentially stored every 18 ms for later(More)
In a recently developed theory of light diffraction by single striated muscle fibers, we considered only the case of normal beam incidence. The present investigation represents both an experimental and theoretical extension of the previous work to arbitrary incident angle. Angle scan profiles over a 50 degrees range of incident angle (+25 degrees to -25(More)
Light diffraction patterns produced by single skeletal muscle fibers and small fiber bundles of Rana pipiens semitendinosus have been examined at rest and during tetanic contraction. The muscle diffraction patterns were recorded with a vidicon camera interfaced to a minicomputer. Digitized video output was analyzed on-line to determine mean sarcomere(More)