This dissertation examines the interaction of the linker histone with DNA and with nucleosomes. The first goal of the project was to characterize the interaction of the linker histone with DNA. Three factors previously reported to influence the linker histone's interaction with DNA were examined: ratio of linker histone to...
Several levels of eukaryotic chromatin structure have
been observed: the nucleosome, the 10 nm and 30 nm fibers
and loop domains, apparently attached to the nuclear
matrix. In this research, the structure and function of
chromatin at two of these levels was investigated, with
studies on both nucleosome positioning and...
The nucleosome appears to be the basic structural unit of the
eukaryotic chromosome. The usual nucleosome preparation, isolated
from a micrococcal nuclease digest of nuclei, is heterogenous in DNA
length and protein composition with some particles containing spacer
DNA and associated protein. This heterogeneity complicated physical
and reconstitution studies. As...
Methods are presented to acquire data from analytical ultracentrifugation experiments
by computer using the absorption optical scanning system of the Beckman Model-E
ultracentrifuge. A computer program was written which analyzes sedimentation velocity
experiments by the van Holde - Weischet method and by the second moment method. The van
Holde -...
Monomer-tetramer association equilibrium and the oxygen
binding of the hemocyanin from Callianassa californiensis
were measured at a number of pH values and magnesium
ion concentrations. Magnesium binding of the hemocyanin
was also measured at several pH values. A thermodynamic
model, which satisfied the constraints from the experimental
results, was developed...
Understanding the structure of the 30 nm fiber in chromatin is relevant to understanding eukaryotic replication and transcription. The major controversy among the models of the fiber concerns the disposition of the linker DNA, the DNA between adjacent nucleosomes, and the location of the linker histones. To determine if the...
By using immobilized trypsin, I have been able to
prepare well-defined, stable trypsinized nucleosomes. The
difficulties of lacking of control in the extent of
trypsinization, which were encountered in previous studies
with the use of free trypsin, have been eliminated. The
nucleosomes and oligonucleosomes prepared by immobilized
trypsin are suitable...