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Full-Text Articles in Molecular Biology
Quaternary Interactions And Supercoiling Modulate The Cooperative Dna Binding Of Agt, Manana Melikishvili, Michael G. Fried
Quaternary Interactions And Supercoiling Modulate The Cooperative Dna Binding Of Agt, Manana Melikishvili, Michael G. Fried
Center for Structural Biology Faculty Publications
Human O6-alkylguanine-DNA alkyltransferase (AGT) repairs mutagenic O6-alkylguanine and O4-alkylthymine adducts in single-stranded and duplex DNAs. The search for these lesions, through a vast excess of competing, unmodified genomic DNA, is a mechanistic challenge that may limit the repair rate in vivo. Here, we examine influences of DNA secondary structure and twist on protein–protein interactions in cooperative AGT complexes formed on lesion-free DNAs that model the unmodified parts of the genome. We used a new approach to resolve nearest neighbor (nn) and long-range (lr) components from the ensemble-average cooperativity, ωave. We found …
The Cγ Subunit Is A Unique Isozyme Of The Camp-Dependent Protein Kinase, Stephen J. Beebe, Paul Salomonsky, Tore Jahnsen, Yixin Li
The Cγ Subunit Is A Unique Isozyme Of The Camp-Dependent Protein Kinase, Stephen J. Beebe, Paul Salomonsky, Tore Jahnsen, Yixin Li
Bioelectrics Publications
There are at least three isozymes (Cα, Cβ, and Cγ) of the mammalian catalytic (C) subunit of cAMP-dependent protein kinase (PKA) (Beebe, S., Oyen, O., Sandberg, M., Froysa, A., Hansson, V., and Jahnsen, T. (1990) Mol. Endocrinol. 4, 465-475). To compare the Cγ and Cα isozymes, the respective cDNAs were expressed in permanently transformed Kin-8 PKA-deficient Y1 adrenal cells using the mouse metallothionein promoter. The recombinant C subunits were characterized as immunoreactive, zinc-inducible, cAMP-dependent kinase activities. In contrast to Cα, histone was a better substrate than Leu-Arg-Arg-Ala-Ser-Leu-Gly (Kemptide) for Cγ. Furthermore, Cγ histone kinase activity was not inhibited by the …
Cell Surface-Binding Sites For Progesterone Mediate Calcium Uptake In Human Sperm, Peter F. Blackmore, Joseph Neulan, Frank Lattanzio, Stephen J. Beebe
Cell Surface-Binding Sites For Progesterone Mediate Calcium Uptake In Human Sperm, Peter F. Blackmore, Joseph Neulan, Frank Lattanzio, Stephen J. Beebe
Bioelectrics Publications
Recent studies (e.g. Blackmore, P. F., Beebe, S. J., Danforth, D. R., and Alexander, N.) (1990) J. Biol. Chem. 265, 1376-1380) have shown that in human sperm, progesterone produces a rapid increase in intracellular free calcium ([Ca2+]i) and an induction of the acrosome reaction (e.g. Osman, R. A., Andria, M. L., Jones, A. D., and Meizel, S. (1989) Biochem. Biophys. Res. Commun. 160, 828-833). In this study, the location of progesterone receptors on the cell surface of human sperm was identified using progesterone immobilized on bovine serum albumin (BSA) (progesterone 3-(O-carboxymethyl)oxime:BSA) as well as progesterone and its 3-O-carboxymethyloxime derivative. Using …
Discriminative Insulin Antagonism Of Stimulatory Effects Of Various Camp Analogs On Adipocyte Lipolysis And Hepatocyte Glycogenolysis, Stephen J. Beebe, J. Bruce Redmon, Peter F. Blackmore, Jackie D. Corbin
Discriminative Insulin Antagonism Of Stimulatory Effects Of Various Camp Analogs On Adipocyte Lipolysis And Hepatocyte Glycogenolysis, Stephen J. Beebe, J. Bruce Redmon, Peter F. Blackmore, Jackie D. Corbin
Bioelectrics Publications
Although insulin effectively blocked hormone-stimulated glycerol output in adipocytes or phosphorylase activation in hepatocytes, the inhibitory effect of insulin on cAMP analog-stimulated cells depended on the cAMP analog used. Of the 20 analogs tested in adipocytes and 13 tested in hepatocytes, the effects of about half of them were effectively blocked by insulin, whereas the effects of many of them were not inhibited at all. In order to approach the explanation for this discriminative insulin action, the inhibitory effects of insulin on the responses to the analogs in the intact cells were correlated with the in vitro cAMP analog specificity …
Purification And Characterization Of A Camp- And Ca2+-Calmodulin-Independent Glycogen Synthase Kinase From Porcine Renal Cortex, Stephen J. Beebe, Erwin M. Reimann, Keith K. Schlender
Purification And Characterization Of A Camp- And Ca2+-Calmodulin-Independent Glycogen Synthase Kinase From Porcine Renal Cortex, Stephen J. Beebe, Erwin M. Reimann, Keith K. Schlender
Bioelectrics Publications
We recently reported the partial purification of a cAMP-independent and Ca2+-calmodulin-independent glycogen synthase kinase from porcine renal cortex (Schlender, K. K., Beebe, S. J., and Reimann, E. M. (1981) Cold Spring Harbor Conf. Cell Proliferation, 389-400). Subsequent purification indicated that the enzyme preparation consisted of at least three forms of glycogen synthase kinase which could be resolved by ATP gradient elution from aminoethylphosphate-agarose (AEP-agarose). The predominant form of glycogen synthase kinase, which eluted from AEP-agarose between 2 and 6 mM ATP, was purified approximately 800-fold and is designated GSK-A1. It had a molecular weight of 45,000-50,000 as determined …
Two Classes Of Camp Analogs Which Are Selective For The Two Different Camp-Binding Sites Of Type Ii Protein Kinase Demonstrate Synergism When Added Together To Intact Adipocytes, Stephen J. Beebe, Rob Holloway, Stephen R. Rannels, Jackie D. Corbin
Two Classes Of Camp Analogs Which Are Selective For The Two Different Camp-Binding Sites Of Type Ii Protein Kinase Demonstrate Synergism When Added Together To Intact Adipocytes, Stephen J. Beebe, Rob Holloway, Stephen R. Rannels, Jackie D. Corbin
Bioelectrics Publications
Twenty-five cyclic nucleotide analogs were tested individually to act as lipolytic agents and to activate adipocyte protein kinase. The lipolytic potency of individual analogs correlated better with their K(a) for protein kinase and their lipophilicity rather than with either parameters alone. Some of the most potent lipolytic analogs had high I50 values for the particulate low K(m) cAMP phosphodiesterase suggesting that their effect was not due to raising endogenous cAMP levels through inhibition of phosphodiesterase. The most potent lipolytic analogs contained a thio moiety at the C-8 or C-6 position. These analogs exhibited concave upward dose-response curves. At high concentrations …