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R D Todd

Publications and source records attributed to R D Todd.

97 records · Page 6Linked to original sources
PubMed1981

Structure of the yeast mitochondrial adenosine triphosphatase. Results of trypsin degradation.

A comparison was made of the subunit sensitivities of the F1-ATPase and the Triton-solubilized ATPase complex to trypsin degradation. The dissociation of the F1-ATPase from ATPase complex increased the trypsin sensitivity of subunit 3 by a factor of 2 and increased the sensitivity of a particular trypsin site (or group of sites) on subunit 1 by 7-fold. The overall degradation of subunits 1 and 2 appears to be the same in solubilized ATPase complex and the F1-ATPase. Implications of these findings for structural models of the ATPase complex are discussed.

Adenosine Triphosphatases↗
PubMed1980

The yeast mitochondrial adenosine triphosphatase complex. Subunit stoichiometry and physical characterization.

Immunoprecipitation of uniformly labeled yeast submitochondrial preparations using a subunit-specific or a holoenzyme antiserum has been employed to determine the subunit stoichiometry of the oligomycin-sensitive ATPase complex. The Triton-solubilized enzyme consists of 10 types of subunits. The number of copies of each subunit, in order of decreasing molecular weight, is 3:3:1:2:1:2:2:1:2:3. on the basis of the stoichiometry data, the ATPase complex has a molecular weight of 5.8 x 10(5) and contains a minimum of 20 polypeptide chains. Analysis of water-soluble ATPase (F1-ATPase) indicates that the stoichiometry of the three largest subunits of the enzyme is preserved in the absence of the other subunits. The molecular weights of both forms of the ATPase, derived from stoichiometry data, agree well with measurements obtained from gel filtration and sedimentation studies. The implications of these data for the structure, function, and assembly of the complex are discussed.

Adenosine Triphosphatases↗
PubMed1979

Overall pathway of mononucleosome production.

Five electrophoretically distinguishable classes of mononucleosomes (MI, MII, ...MV) are produced upon treatment of mammalian nuclear chromatin with micrococcal nuclease. These five forms differ in their initial DNA lengths, relative mass proportions, stability, contents of histone H1, and presence of certain nonhistone proteins. A new "chromatin fingerprinting" technique has been developed in order to trace nuclease-mediated interconversions between these mononucleosomes and their polynucleosomal precursors. Application of this technique, together with earlier findings from this laboratory, has made possible the elucidation of the overall pathway of nuclease cleavage of chromatin which leads to the production and interconversion of these mononucleosomes, and has permitted reconstruction of the organization of these mononucleosomes in undigested chromatin...

Animals↗
PubMed1977

Heterogeneity in nucleosome spacing.

The organization of spacer DNA connecting 160 base-pair cores of bovine thymus polynucleosomes has been studied by a combination of biochemical and electron microscopic techniques. The results reveal that a major fraction of chromatin consists of a spectrum of repeating units; these differ from each other by up to 20 base-pairs due to variation in spacer DNA length. Those polynucleosomes which have larger spacer DNA lengths are processed by micrococcal nuclease to mononucleosomes more rapidly than those organized with shorter spacers. Although a distribution of spacer DNA lengths exists, a significant proportion of spacers that are nearest neighbors share common DNA lengths. These findings imply that functional roles may be related to the manners in which spacers are organized along chromatin fibers.

Animals↗