Daniel E. Koshland
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View article: Insights into the serine protease mechanism from atomic resolution structures of trypsin reaction intermediates
Insights into the serine protease mechanism from atomic resolution structures of trypsin reaction intermediates Open
Atomic resolution structures of trypsin acyl-enzymes and a tetrahedral intermediate analog, along with previously solved structures representing the Michaelis complex, are used to reconstruct events in the catalytic cycle of this classic s…
View article: Proteomics and Models for Enzyme Cooperativity
Proteomics and Models for Enzyme Cooperativity Open
Cooperativity is a phenomenon of universal importance in biological systems and has almost as much variety as it has ubiquity. In virtually all ecosystems the cooperativity of groups, species, and individual organisms is evident. The coope…
View article: A clogged gutter mechanism for protease inhibitors
A clogged gutter mechanism for protease inhibitors Open
A classical peptide inhibitor of serine proteases that is hydrolyzed ≈10 7 times more slowly than a good substrate is shown to form an acyl–enzyme intermediate rapidly. Despite this quick first step, further reaction is slowed dramatically…
View article: Differential Effects of Unnatural Sialic Acids on the Polysialylation of the Neural Cell Adhesion Molecule and Neuronal Behavior
Differential Effects of Unnatural Sialic Acids on the Polysialylation of the Neural Cell Adhesion Molecule and Neuronal Behavior Open
In this study we have examined how unnatural sialic acids can alter polysialic acid expression and influence the adhesive properties of the neural cell adhesion molecule (NCAM). Unnatural sialic acids are generated by metabolic conversion …
View article: Propagating conformational changes over long (and short) distances in proteins
Propagating conformational changes over long (and short) distances in proteins Open
The problem of the propagation of conformational changes over long distances or through a closely packed protein is shown to fit a model of a ligand-induced conformational change between two protein states selected by evolution. Moreover, …
View article: Biosynthetic incorporation of unnatural sialic acids into polysialic acid on neural cells
Biosynthetic incorporation of unnatural sialic acids into polysialic acid on neural cells Open
In this study we demonstrate that polysialyltransferases are capable of accepting unnatural substrates in terminally differentiated human neurons. Polysialyltransferases catalyze the glycosylation of the neural cell adhesion molecule (NCAM…
View article: The Escherichia coli aspartate receptor: sequence specificity of a transmembrane helix studied by hydrophobic-biased random mutagenesis
The Escherichia coli aspartate receptor: sequence specificity of a transmembrane helix studied by hydrophobic-biased random mutagenesis Open
The Escherichia coli aspartate receptor is a dimer with two transmembrane sequences per monomer that connect a periplasmic ligand binding domain to a cytoplasmic signaling domain. The method of 'hydrophobic-biased' random mutagenesis, that…
View article: Converting a transmembrane receptor to a soluble receptor: Recognition domain to effector domain signaling after excision of the transmembrane domain
Converting a transmembrane receptor to a soluble receptor: Recognition domain to effector domain signaling after excision of the transmembrane domain Open
The bacterial aspartate receptor was reconstructed to eliminate the transmembrane domain, thus connecting the recognition domain directly to the effector domain. The resulting soluble receptor folded correctly and was no longer an integral…
View article: An Aspartate/Insulin Receptor Chimera Mitogenically Activates Fibroblasts
An Aspartate/Insulin Receptor Chimera Mitogenically Activates Fibroblasts Open
A gene encoding the ligand-binding domain of the Escherichia coli aspartate receptor fused to the cytoplasmic domain of the insulin receptor tyrosine kinase to produce the chimeric aspartate insulin receptor (AIR) was expressed in mammalia…
View article: HOW TO GET PAID FOR HAVING FUN
HOW TO GET PAID FOR HAVING FUN Open
When writing a prefatory chapter for Annual Reviews a scientist is confronted with the question of what in his or her life might be interesting to others. In my case I was appalled at the absence of material that generates good novels: no …
View article: Computational method for relative binding energies of enzyme‐substrate complexes
Computational method for relative binding energies of enzyme‐substrate complexes Open
A computational method for estimating the relative binding free energies of enzyme‐substrate complexes is described that combines electrostatic and solvation models and X‐ray crystallographic data. The polar contribution is evaluated by th…
View article: Determination of in Vivo Phosphorylation Sites in Protein Kinase C
Determination of in Vivo Phosphorylation Sites in Protein Kinase C Open
The primary structure of rat protein kinase C beta II was probed by high pressure liquid chromatography directly coupled to an electrospray ionization mass spectrometer and by high energy collision-induced dissociation analysis to identify…
View article: The N-terminal Cytoplasmic Tail of the Aspartate Receptor Is Not Essential in Signal Transduction of Bacterial Chemotaxis
The N-terminal Cytoplasmic Tail of the Aspartate Receptor Is Not Essential in Signal Transduction of Bacterial Chemotaxis Open
To determine the role in transmembrane signaling of the N-terminal peptide of the first transmembrane region of the aspartate receptor, it was subjected to extensive mutagenesis. Drastic changes did not alter the chemotactic ability of the…
View article: Mutagenesis and Laue Structures of Enzyme Intermediates: Isocitrate Dehydrogenase
Mutagenesis and Laue Structures of Enzyme Intermediates: Isocitrate Dehydrogenase Open
Site-directed mutagenesis and Laue diffraction data to 2.5 Å resolution were used to solve the structures of two sequential intermediates formed during the catalytic actions of isocitrate dehydrogenase. Both intermediates are distinct from…
View article: Neurosecretory habituation in PC12 cells: modulation during parallel habituation.
Neurosecretory habituation in PC12 cells: modulation during parallel habituation. Open
PC12 cells habituate during repetitive stimulation with acetylcholine, bradykinin, or high potassium. Interspersing these stimulants did not affect the rate of habituation of the others, but it could modulate the amplitude of the norepinep…
View article: Contributions made by individual methylation sites of the Escherichia coli aspartate receptor to chemotactic behavior.
Contributions made by individual methylation sites of the Escherichia coli aspartate receptor to chemotactic behavior. Open
To determine the extent to which chemotactic behavior depends on methylation at multiple sites, chemotaxis assays were performed on bacteria that expressed mutant aspartate receptors in which methylation site residues were mutated from glu…
View article: Interactions between the Methylation Sites of the Escherichia coli Aspartate Receptor Mediated by the Methyltransferase
Interactions between the Methylation Sites of the Escherichia coli Aspartate Receptor Mediated by the Methyltransferase Open
Mutations made at and near the methylation sites of the Escherichia coli aspartate receptor were found to affect the methylation rates of the remaining methylation sites. The results supported a model in which the methyltransferase enzyme …
View article: Mutagenic studies of the interaction between the aspartate receptor and methyltransferase from Escherichia coli
Mutagenic studies of the interaction between the aspartate receptor and methyltransferase from Escherichia coli Open
The 4 glutamate residues that are the sites of methylation in the aspartate receptor, which mediates bacterial chemotaxis, were systematically mutated to aspartate residues. None of the aspartate residues were methylated. In each case, the…
View article: Conditional activation of cAMP signal transduction by protein kinase C. The effect of phorbol esters on adenylyl cyclase in permeabilized and intact cells.
Conditional activation of cAMP signal transduction by protein kinase C. The effect of phorbol esters on adenylyl cyclase in permeabilized and intact cells. Open
To understand the convergence of cAMP and protein kinase C signal transduction, adenylyl cyclase isozyme identification and biochemical studies were performed on the HT4 neural cell line. In HT4 cells, basal cAMP production by adenylyl cyc…
View article: Regulation of neurosecretory habituation by cAMP
Regulation of neurosecretory habituation by cAMP Open
The role of adaptation in receptors was studied with regard to the processing of neural information by cAMP in PC12 cells. Both secretin and adenosine A2 receptors elevated cAMP levels. During prolonged stimulation, secretin receptors demo…
View article: Purification and characterization of the periplasmic domain of the aspartate chemoreceptor.
Purification and characterization of the periplasmic domain of the aspartate chemoreceptor. Open
In order to facilitate biochemical studies of cell-surface receptors, a plasmid allowing the expression of the periplasmic domain of the aspartate receptor from Salmonella typhimurium as a soluble periplasmic protein has been constructed. …
View article: The joys and vicissitudes of protein science
The joys and vicissitudes of protein science Open
When invited to look back over a previous life in protein chemistry, I was a little uncertain as to how to proceed but thought that some of my experiences as an author and the inevitable interactions with editors in some of my past researc…
View article: Refined Structures of the Ligand-binding Domain of the Aspartate Receptor from Salmonella typhimurium
Refined Structures of the Ligand-binding Domain of the Aspartate Receptor from Salmonella typhimurium Open
The aspartate receptor is a transmembrane-signalling protein that mediates chemotaxis behaviour in bacteria. Aspartate receptors in Salmonella typhimurium and Escherichia coli exist as dimers of two subunits in the presence as well as in t…
View article: The three-dimensional structure of the ligand-binding domain of a wild-type bacterial chemotaxis receptor. Structural comparison to the cross-linked mutant forms and conformational changes upon ligand binding
The three-dimensional structure of the ligand-binding domain of a wild-type bacterial chemotaxis receptor. Structural comparison to the cross-linked mutant forms and conformational changes upon ligand binding Open
The three-dimensional structures of the ligand-binding domain of the wild-type Salmonella typhimurium aspartate receptor have been determined in the absence (apo) and presence of bound aspartate (complex) and compared to a cross-linked mut…
View article: Three‐dimensional structural model of the serine receptor ligand‐binding domain
Three‐dimensional structural model of the serine receptor ligand‐binding domain Open
Computer‐based homology modeling techniques were used to construct a three‐dimensional model of the Escherichia coli serine receptor ligand‐binding domain based on the crystal structure of the Salmonella typhimurium aspartate receptor and …